Word2Vec-Skipgram-Keras.ipynb

{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "<img src=\"../Pics/MLSb-T.png\" width=\"160\">\n",
    "<br><br>\n",
    "<center><u><H1>Word2Vec-Skipgram-Keras</H1></u></center>"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [
    {
     "name": "stderr",
     "output_type": "stream",
     "text": [
      "Using TensorFlow backend.\n"
     ]
    }
   ],
   "source": [
    "import tensorflow as tf\n",
    "from keras.backend.tensorflow_backend import set_session\n",
    "config = tf.ConfigProto()\n",
    "config.gpu_options.allow_growth = True\n",
    "config.log_device_placement = True\n",
    "sess = tf.Session(config=config)\n",
    "set_session(sess)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [
    {
     "name": "stderr",
     "output_type": "stream",
     "text": [
      "C:\\Anaconda36\\envs\\tf111_gpu\\lib\\site-packages\\gensim\\utils.py:1212: UserWarning: detected Windows; aliasing chunkize to chunkize_serial\n",
      "  warnings.warn(\"detected Windows; aliasing chunkize to chunkize_serial\")\n"
     ]
    }
   ],
   "source": [
    "import numpy as np\n",
    "from keras.models import Sequential, Model\n",
    "from keras.layers import Embedding, Reshape, Activation, Input\n",
    "from keras.layers.merge import Dot\n",
    "from keras.utils import np_utils\n",
    "from keras.utils.data_utils import get_file\n",
    "from keras.preprocessing.text import Tokenizer\n",
    "from keras.preprocessing.sequence import skipgrams\n",
    "import gensim"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [],
   "source": [
    "from string import punctuation\n",
    "from nltk.corpus import stopwords\n",
    "from nltk.tokenize import word_tokenize\n",
    "from nltk.tokenize import sent_tokenize\n",
    "from nltk.stem import WordNetLemmatizer"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [],
   "source": [
    "remove_terms = punctuation + '0123456789'"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [],
   "source": [
    "def preprocessing(text):\n",
    "    words = word_tokenize(text)\n",
    "    tokens = [w for w in words if w.lower() not in remove_terms]\n",
    "    #stopw = stopwords.words('english')\n",
    "    #tokens = [token for token in tokens if token not in stopw]\n",
    "    # remove words less than three letters\n",
    "    #tokens = [word for word in tokens if len(word)>=3]\n",
    "    # remove remaining tokens that are not alphabetic\n",
    "    tokens = [word for word in tokens if word.isalpha()]\n",
    "    # lemmatize\n",
    "    lemma = WordNetLemmatizer()\n",
    "    tokens = [lemma.lemmatize(word) for word in tokens]\n",
    "    preprocessed_text = ' '.join(tokens)\n",
    "    return preprocessed_text"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [],
   "source": [
    "#path = get_file('cosmos.txt', origin=\"https://www.gutenberg.org/files/8172/8172-0.txt\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [],
   "source": [
    "corpus = open(\"../data/History_of_Astronomy.txt\", encoding=\"utf8\").readlines()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "['Project Gutenberg EBook of History of Astronomy by George Forbes',\n",
       " 'Title History of Astronomy',\n",
       " 'Author George Forbes',\n",
       " 'Illustration SIR ISAAC NEWTON From the bust by Roubiliac In Trinity',\n",
       " 'College Cambridge',\n",
       " 'HISTORY OF ASTRONOMY',\n",
       " 'BY',\n",
       " 'GEORGE FORBES',\n",
       " 'INST',\n",
       " 'FORMERLY PROFESSOR OF NATURAL PHILOSOPHY ANDERSON COLLEGE GLASGOW',\n",
       " 'AUTHOR OF THE TRANSIT OF VENUS RENDU THEORY OF THE GLACIERS OF',\n",
       " 'SAVOY ETC',\n",
       " 'CONTENTS',\n",
       " 'PREFACE',\n",
       " 'BOOK I THE GEOMETRICAL PERIOD',\n",
       " 'PRIMITIVE ASTRONOMY AND ASTROLOGY',\n",
       " 'ANCIENT ASTRONOMY CHINESE AND CHALDÆANS',\n",
       " 'ANCIENT GREEK ASTRONOMY',\n",
       " 'THE REIGN OF EPICYCLES FROM PTOLEMY TO COPERNICUS',\n",
       " 'BOOK II THE DYNAMICAL PERIOD',\n",
       " 'DISCOVERY OF THE TRUE SOLAR SYSTEM TYCHO BRAHE KEPLER',\n",
       " 'GALILEO AND THE TELESCOPE NOTIONS OF GRAVITY BY HORROCKS ETC',\n",
       " 'SIR ISAAC NEWTON LAW OF UNIVERSAL GRAVITATION',\n",
       " 'NEWTON SUCCESSORS HALLEY EULER LAGRANGE LAPLACE ETC',\n",
       " 'DISCOVERY OF NEW PLANETS HERSCHEL PIAZZI ADAMS AND LE',\n",
       " 'VERRIER',\n",
       " 'BOOK III OBSERVATION',\n",
       " 'INSTRUMENTS OF PRECISION SIZE OF THE SOLAR SYSTEM',\n",
       " 'HISTORY OF THE TELESCOPE SPECTROSCOPE',\n",
       " 'BOOK IV THE PHYSICAL PERIOD',\n",
       " 'THE SUN',\n",
       " 'THE MOON AND PLANETS',\n",
       " 'COMETS AND METEORS',\n",
       " 'THE STARS AND NEBULÆ',\n",
       " 'INDEX',\n",
       " 'PREFACE',\n",
       " 'An attempt ha been made in these page to trace the evolution of',\n",
       " 'intellectual thought in the progress of astronomical discovery and',\n",
       " 'by recognising the different point of view of the different age to',\n",
       " 'give due credit even to the ancient No one can expect in a history',\n",
       " 'of astronomy of limited size to find a treatise on practical or on',\n",
       " 'theoretical astronomy nor a complete descriptive astronomy and',\n",
       " 'still le a book on speculative astronomy Something of each of',\n",
       " 'these is essential however for tracing the progress of thought and',\n",
       " 'knowledge which it is the object of this History to describe',\n",
       " 'The progress of human knowledge is measured by the increased habit of',\n",
       " 'looking at fact from new point of view a much a by the',\n",
       " 'accumulation of fact The mental capacity of one age doe not seem to',\n",
       " 'differ from that of other age but it is the imagination of new',\n",
       " 'point of view that give a wider scope to that capacity And this is',\n",
       " 'cumulative and therefore progressive Aristotle viewed the solar',\n",
       " 'system a a geometrical problem Kepler and Newton converted the point',\n",
       " 'of view into a dynamical one Aristotle mental capacity to',\n",
       " 'understand the meaning of fact or to criticise a train of reasoning',\n",
       " 'may have been equal to that of Kepler or Newton but the point of view',\n",
       " 'wa different',\n",
       " 'Then again new point of view are provided by the invention of new',\n",
       " 'method in that system of logic which we call mathematics All that',\n",
       " 'mathematics can do is to assure u that a statement A is equivalent to',\n",
       " 'statement B C D or is one of the fact expressed by the statement',\n",
       " 'B C D so that we may know if B C and D are true then A is true',\n",
       " 'To many people our inability to understand all that is contained in',\n",
       " 'statement B C and D without the cumbrous process of a mathematical',\n",
       " 'demonstration prof the feebleness of the human mind a a logical',\n",
       " 'machine For it required the new point of view imagined by Newton',\n",
       " 'analysis to enable people to see that so far a planetary orbit are',\n",
       " 'concerned Kepler three law B C D were identical with Newton',\n",
       " 'law of gravitation A No one recognises more than the mathematical',\n",
       " 'astronomer this feebleness of the human intellect and no one is more',\n",
       " 'conscious of the limitation of the logical process called',\n",
       " 'mathematics which even now ha not solved directly the problem of',\n",
       " 'only three body',\n",
       " 'These reflection arising from the writing of this History go to',\n",
       " 'explain the invariable humility of the great mathematical astronomer',\n",
       " 'Newton comparison of himself to the child on the seashore applies to',\n",
       " 'them all As each new discovery open up it may be boundless ocean',\n",
       " 'for investigation for wonder and for admiration the great',\n",
       " 'astronomer refusing to accept mere hypothesis a true have founded',\n",
       " 'upon these discovery a science a exact in it observation of fact',\n",
       " 'a in theory So it is that these men who have built up the most',\n",
       " 'sure and most solid of all the science refuse to invite others to',\n",
       " 'join them in vain speculation The writer ha therefore in this',\n",
       " 'short History tried to follow that great master Airy whose pupil he',\n",
       " 'wa and the key to whose character wa exactness and accuracy and he',\n",
       " 'recognises that Science is impotent except in her own limited sphere',\n",
       " 'It ha been necessary to curtail many part of the History in the',\n",
       " 'attempt perhaps a hopeless one to lay before the reader in a limited',\n",
       " 'space enough about each age to illustrate it tone and spirit the',\n",
       " 'ideal of the worker the gradual addition of new point of view and',\n",
       " 'of new mean of investigation',\n",
       " 'It would indeed be a pleasure to entertain the hope that these page',\n",
       " 'might among new recruit arouse an interest in the greatest of all',\n",
       " 'the science or that those who have handled the theoretical or',\n",
       " 'practical side might be led by them to read in the original some of',\n",
       " 'the classic of astronomy Many student have much compassion for the',\n",
       " 'schoolboy of who is not allowed the luxury of learning the art',\n",
       " 'of reasoning from him who still remains it greatest',\n",
       " 'exponent Euclid These student pity also the man of who',\n",
       " 'is not to be allowed to read in the original Latin of the brilliant',\n",
       " 'Kepler how he wa able by observation taken from a moving platform',\n",
       " 'the earth of the direction of a moving object Mars to deduce the',\n",
       " 'exact shape of the path of each of these planet and their actual',\n",
       " 'position on these path at any time Kepler masterpiece is one of',\n",
       " 'the most interesting book that wa ever written combining wit',\n",
       " 'imagination ingenuity and certainty',\n",
       " 'Lastly it must be noted that a a History of England can not deal',\n",
       " 'with the present Parliament so also the unfinished research and',\n",
       " 'untested hypothesis of many astronomer of can not be',\n",
       " 'included among the record of the History of Astronomy The writer',\n",
       " 'regret the necessity that thus arises of leaving without mention the',\n",
       " 'name of many who are now making history in astronomical work',\n",
       " 'F',\n",
       " '',\n",
       " 'BOOK I THE GEOMETRICAL PERIOD',\n",
       " 'PRIMITIVE ASTRONOMY AND ASTROLOGY',\n",
       " 'The growth of intelligence in the human race ha it counterpart in',\n",
       " 'that of the individual especially in the earliest stage',\n",
       " 'Intellectual activity and the development of reasoning power are in',\n",
       " 'both case based upon the accumulation of experience and on the',\n",
       " 'comparison classification arrangement and nomenclature of these',\n",
       " 'experience During the infancy of each the succession of event can',\n",
       " 'be watched but there can be no anticipation',\n",
       " 'Experience alone in both case lead to the idea of cause and effect',\n",
       " 'a a principle that seems to dominate our present universe a a rule',\n",
       " 'for predicting the course of event and a a guide to the choice of a',\n",
       " 'course of action This idea of cause and effect is the most potent',\n",
       " 'factor in developing the history of the human race a of the',\n",
       " 'individual',\n",
       " 'In no realm of nature is the principle of cause and effect more',\n",
       " 'conspicuous than in astronomy and we fall into the habit of thinking',\n",
       " 'of it law a not only being unchangeable in our universe but',\n",
       " 'necessary to the conception of any universe that might have been',\n",
       " 'substituted in it place The first inhabitant of the world were',\n",
       " 'compelled to accommodate their act to the daily and annual',\n",
       " 'alternation of light and darkness and of heat and cold a much a to',\n",
       " 'the irregular change of weather attack of disease and the fortune',\n",
       " 'of war They soon came to regard the influence of the sun in',\n",
       " 'connection with light and heat a a cause This led to a search for',\n",
       " 'other sign in the heaven If the appearance of a comet wa sometimes',\n",
       " 'noted simultaneously with the death of a great ruler or an eclipse',\n",
       " 'with a scourge of plague these might well be looked upon a cause in',\n",
       " 'the same sense that the veering or backing of the wind is regarded a',\n",
       " 'a cause of fine or foul weather',\n",
       " 'For these reason we find that the earnest men of all age have',\n",
       " 'recorded the occurrence of comet eclipse new star meteor',\n",
       " 'shower and remarkable conjunction of the planet a well a',\n",
       " 'plague and famine flood and drought war and the death of great',\n",
       " 'ruler Sometimes they thought they could trace connection which',\n",
       " 'might lead them to say that a comet presaged famine or an eclipse',\n",
       " 'war',\n",
       " 'Even if these men were sometimes led to evolve law of cause and',\n",
       " 'effect which now seem to u absurd let u be tolerant and gratefully',\n",
       " 'acknowledge that these astrologer when they suggested such working',\n",
       " 'hypothesis were laying the foundation of observation and deduction',\n",
       " 'If the ancient Chaldæans gave to the planetary conjunction an',\n",
       " 'influence over terrestrial event let u remember that in our own',\n",
       " 'time people have searched for connection between terrestrial',\n",
       " 'condition and period of unusual prevalence of sun spot while De la',\n",
       " 'Rue Loewy and Balfour Stewart thought they found a connection',\n",
       " 'between display and the planetary position Thus we find',\n",
       " 'scientific men even in our own time responsible for the belief that',\n",
       " 'storm in the Indian Ocean the fertility of German vine famine in',\n",
       " 'India and high or low in Egypt follow the planetary',\n",
       " 'position',\n",
       " 'And again the desire to foretell the weather is so laudable that we',\n",
       " 'can not blame the ancient Greeks for announcing the influence of the',\n",
       " 'moon with a much confidence a it is affirmed in Lord Wolseley',\n",
       " 'Pocket',\n",
       " 'Even if the scientific spirit of observation and deduction astronomy',\n",
       " 'ha sometimes led to erroneous system for predicting terrestrial',\n",
       " 'event astrology we owe to the old astronomer and astrologer alike',\n",
       " 'the deepest gratitude for their diligence in recording astronomical',\n",
       " 'event For out of the scanty record which have survived the',\n",
       " 'destructive act of fire and flood of monarch and mob we have',\n",
       " 'found much that ha helped to a fuller knowledge of the heavenly',\n",
       " 'motion than wa possible without these record',\n",
       " 'So Hipparchus about and Ptolemy a little later were able',\n",
       " 'to use the observation of Chaldæan astrologer a well a those of',\n",
       " 'Alexandrian astronomer and to make some discovery which have',\n",
       " 'helped the progress of astronomy in all age So also Cowell',\n",
       " 'ha examined the mark made on the baked brick used by the Chaldæans',\n",
       " 'for recording the eclipse of and and ha thereby',\n",
       " 'been enabled in the last few year to correct the lunar table of',\n",
       " 'Hansen and to find a more accurate value for the secular acceleration',\n",
       " 'of the moon longitude and the node of her orbit than any that could',\n",
       " 'be obtained from modern observation made with instrument of the',\n",
       " 'highest precision',\n",
       " 'So again Hind wa enabled to trace back the period during',\n",
       " 'which Halley comet ha been a member of the solar system and to',\n",
       " 'identify it in the Chinese observation of comet a far back a',\n",
       " 'Cowell and Cromellin extended the date to In the same',\n",
       " 'way the comet ha been traced back in the Chinese record to',\n",
       " '',\n",
       " 'The theoretical view founded on Newton great law of universal',\n",
       " 'gravitation led to the conclusion that the inclination of the earth',\n",
       " 'equator to the plane of her orbit the obliquity of the ecliptic ha',\n",
       " 'been diminishing slowly since prehistoric time and this fact ha',\n",
       " 'been confirmed by Egyptian and Chinese observation on the length of',\n",
       " 'the shadow of a vertical pillar made thousand of year before the',\n",
       " 'Christian era in summer and winter',\n",
       " 'There are other reason why we must be tolerant of the crude notion',\n",
       " 'of the ancient The historian wishing to give credit wherever it may',\n",
       " 'be due is met by two difficulty Firstly only a few record of',\n",
       " 'very ancient astronomy are extant and the authenticity of many of',\n",
       " 'these is open to doubt Secondly it is very difficult to divest',\n",
       " 'ourselves of present knowledge and to appreciate the originality of',\n",
       " 'thought required to make the first beginning',\n",
       " 'With regard to the first point we are generally dependent upon',\n",
       " 'history written long after the event The astronomy of Egyptians',\n",
       " 'Babylonians and Assyrians is known to u mainly through the Greek',\n",
       " 'historian and for information about the Chinese we rely upon the',\n",
       " 'research of traveller and missionary in comparatively recent',\n",
       " 'time The testimony of the Greek writer ha fortunately been',\n",
       " 'confirmed and we now have in addition a mass of fact translated from',\n",
       " 'the original sculpture papyrus and inscribed brick dating back',\n",
       " 'thousand of year',\n",
       " 'In attempting to appraise the effort of the beginner we must',\n",
       " 'remember that it wa natural to look upon the earth a all the first',\n",
       " 'astronomer did a a circular plane surrounded and bounded by the',\n",
       " 'heaven which wa a solid vault or hemisphere with it concavity',\n",
       " 'turned downwards The star seemed to be fixed on this vault the',\n",
       " 'moon and later the planet were seen to crawl over it It wa a',\n",
       " 'great step to look on the vault a a hollow sphere carrying the sun',\n",
       " 'too It must have been difficult to believe that at midday the star',\n",
       " 'are shining a brightly in the blue sky a they do at night It must',\n",
       " 'have been difficult to explain how the sun having set in the west',\n",
       " 'could get back to rise in the east without being seen it wa',\n",
       " 'always the same sun It wa a great step to suppose the earth to be',\n",
       " 'spherical and to ascribe the diurnal motion to it rotation',\n",
       " 'Probably the greatest step ever made in astronomical theory wa the',\n",
       " 'placing of the sun moon and planet at different distance from the',\n",
       " 'earth instead of having them stuck on the vault of heaven It wa a',\n",
       " 'transition from flatland to a space of three dimension',\n",
       " 'Great progress wa made when systematic observation began such a',\n",
       " 'following the motion of the moon and planet among the star and the',\n",
       " 'inferred motion of the sun among the star by observing their',\n",
       " 'the time of year when a star',\n",
       " 'would first be seen to rise at sunrise and when it could last be seen',\n",
       " 'to rise at sunset The grouping of the star into constellation and',\n",
       " 'recording their place wa a useful observation The theoretical',\n",
       " 'prediction of eclipse of the sun and moon and of the motion of the',\n",
       " 'planet among the star became later the highest goal in astronomy',\n",
       " 'To not one of the above important step in the progress of astronomy',\n",
       " 'can we assign the author with certainty Probably many of them were',\n",
       " 'independently taken by Chinese Indian Persian Tartar Egyptian',\n",
       " 'Babylonian Assyrian Phoenician and Greek astronomer And we have',\n",
       " 'not a particle of information about the discovery which may have',\n",
       " 'been great by other people by the Druids the Mexicans and the',\n",
       " 'Peruvians for example',\n",
       " 'We do know this that all nation required to have a calendar The',\n",
       " 'solar year the lunar month and the day were the unit and it is',\n",
       " 'owing to their incommensurability that we find so many calendar',\n",
       " 'proposed and in use at different time The only object to be attained',\n",
       " 'by comparing the chronology of ancient race is to fix the actual',\n",
       " 'date of observation recorded and this is not a part of a history of',\n",
       " 'astronomy',\n",
       " 'In conclusion let u bear in mind the limited point of view of the',\n",
       " 'ancient when we try to estimate their merit Let u remember that the',\n",
       " 'first astronomy wa of two dimension the second astronomy wa of',\n",
       " 'three dimension but still purely geometrical Since Kepler day we',\n",
       " 'have had a dynamical astronomy',\n",
       " 'FOOTNOTES',\n",
       " 'Trans xxiii Sun by',\n",
       " 'Stewart Also Trans Also Ernest Brown in',\n",
       " 'Monthly',\n",
       " 'Monthly Sup',\n",
       " 'Illustration CHALDÆAN BAKED BRICK OR TABLET and reverse',\n",
       " 'Containing record of solar eclipse used lately by',\n",
       " 'Cowell for rendering the lunar theory more accurate than wa possible',\n",
       " 'by finest modern observation British Museum collection',\n",
       " 'No',\n",
       " 'Monthly vol',\n",
       " 'E vol',\n",
       " 'ANCIENT ASTRONOMY THE CHINESE AND CHALDÆANS',\n",
       " 'The last section must have made clear the difficulty the way of',\n",
       " 'assigning to the ancient nation their proper place in the development',\n",
       " 'of primitive notion about astronomy The fact that some alleged',\n",
       " 'observation date back to a period before the Chinese had invented the',\n",
       " 'art of writing lead immediately to the question how far tradition can',\n",
       " 'be trusted',\n",
       " 'Our first detailed knowledge wa gathered in the far East by',\n",
       " 'traveller and by the Jesuit priest and wa published in the',\n",
       " 'eighteenth century The Asiatic Society of Bengal contributed',\n",
       " 'translation of Brahmin literature The two principal source of',\n",
       " 'knowledge about Chinese astronomy were supplied first by Father',\n",
       " 'Souciet who in published Astronomical',\n",
       " 'Geographical Chronological and drawn from ancient',\n",
       " 'Chinese book and later by Father who in',\n",
       " 'published of the Chinese Empire translated from',\n",
       " '',\n",
       " 'Bailly in his drew from these and',\n",
       " 'other source the conclusion that all we know of the astronomical',\n",
       " 'learning of the Chinese Indians Chaldæans Assyrians and Egyptians',\n",
       " 'is but the remnant of a far more complete astronomy of which no trace',\n",
       " 'can be found',\n",
       " 'Delambre in his de',\n",
       " 'ridicule the opinion of Bailly and considers that the progress made',\n",
       " 'by all of these nation is insignificant',\n",
       " 'It will be well now to give an idea of some of the astronomy of the',\n",
       " 'ancient not yet entirely discredited China and Babylon may be taken',\n",
       " 'a typical example',\n",
       " 'It would appear that Fohi the first emperor reigned',\n",
       " 'about and shortly afterwards made a sphere to',\n",
       " 'represent the motion of the celestial body It is also mentioned',\n",
       " 'in the book called supposed to have been written in',\n",
       " 'that a similar sphere wa made in the time of Yao',\n",
       " 'It is said that the Emperor Chueni saw five',\n",
       " 'planet in conjunction the same day that the sun and moon were in',\n",
       " 'conjunction This is discussed by Father Martin MSS of De Lisle',\n",
       " 'also by Desvignolles Mem Acad Berlin vol and by',\n",
       " 'Kirsch ditto vol who both found that Mars Jupiter',\n",
       " 'Saturn and Mercury were all between the eleventh and eighteenth',\n",
       " 'degree of Pisces all visible together in the evening on February',\n",
       " 'while on the same day the sun and moon were in',\n",
       " 'conjunction at and that on March the moon wa in',\n",
       " 'conjunction with the other four planet But this need confirmation',\n",
       " 'Yao referred to above gave instruction to his astronomer to',\n",
       " 'determine the position of the solstice and equinox and they',\n",
       " 'reported the name of the star in the place occupied by the sun at',\n",
       " 'these season and in he gave them further order If this',\n",
       " 'account be true it show a knowledge that the vault of heaven is a',\n",
       " 'complete sphere and that star are shining at although',\n",
       " 'eclipsed by the sun brightness',\n",
       " 'It is also asserted in the book called that in the',\n",
       " 'time of Yao the year wa known to have day and that he',\n",
       " 'adopted day and added an intercalary day every four year a in',\n",
       " 'the Julian Calendar This may be true or not but the ancient Chinese',\n",
       " 'certainly seem to have divided the circle into degree To learn',\n",
       " 'the length of the year needed only patient observation a',\n",
       " 'characteristic of the Chinese but many younger nation got into a',\n",
       " 'terrible mess with their calendar from ignorance of the year length',\n",
       " 'It is stated that in the royal astronomer Hi and Ho failed',\n",
       " 'to predict an eclipse It probably created great terror for they were',\n",
       " 'executed in punishment for their neglect If this account be true it',\n",
       " 'mean that in the century some rule for calculating',\n",
       " 'eclipse wa in use Here again patient observation would easily',\n",
       " 'lead to the detection of the cycle known to the',\n",
       " 'Chaldeans a the It consists of lunation and in',\n",
       " 'that time the pole of the moon orbit revolves just once round the',\n",
       " 'pole of the ecliptic and for this reason the eclipse in one cycle',\n",
       " 'are repeated with very slight modification in the next cycle and so',\n",
       " 'on for many century',\n",
       " 'It may be that the neglect of their duty by Hi and Ho and their',\n",
       " 'punishment influenced Chinese astronomy or that the succeeding',\n",
       " 'record have not been available to later scholar but the fact',\n",
       " 'remains that although at long interval observation were made of',\n",
       " 'eclipse comet and falling star and of the position of the',\n",
       " 'solstice and of the obliquity of the ecliptic record become rare',\n",
       " 'until when eclipse began to be recorded once more with some',\n",
       " 'approach to continuity Shortly afterwards notice of comet were',\n",
       " 'added Biot gave a list of these and John Williams in',\n",
       " 'published of Comets from to',\n",
       " 'Extracted from the Chinese',\n",
       " 'With regard to those century concerning which we have no',\n",
       " 'astronomical Chinese record it is fair to state that it is recorded',\n",
       " 'that some century before the Christian era in the reign of',\n",
       " 'all the classical and scientific book that could be',\n",
       " 'found were ordered to be destroyed If true our loss therefrom is a',\n",
       " 'great a from the burning of the Alexandrian library by the Caliph',\n",
       " 'Omar He burnt all the book because he held that they must be either',\n",
       " 'consistent or inconsistent with the Koran and in the one case they',\n",
       " 'were superfluous in the other case objectionable',\n",
       " 'Until the last half century historian were',\n",
       " 'accustomed to look back upon the Greeks who led the world from the',\n",
       " 'fifth to the third century a the pioneer of art literature',\n",
       " 'and science But the excavation and research of later year make u',\n",
       " 'more ready to grant that in science a in art the Greeks only',\n",
       " 'developed what they derived from the Egyptians Babylonians and',\n",
       " 'Assyrians The Greek historian said a much in fact and modern',\n",
       " 'commentator used to attribute the assertion to undue modesty Since',\n",
       " 'however the record of the library have been unearthed it ha been',\n",
       " 'recognised that the Babylonians were in no way inferior in the matter',\n",
       " 'of original scientific investigation to other race of the same era',\n",
       " 'The Chaldæans being the most ancient Babylonians held the same',\n",
       " 'station and dignity in the State a did the priest in Egypt and',\n",
       " 'spent all their time in the study of philosophy and astronomy and the',\n",
       " 'art of divination and astrology They held that the world of which we',\n",
       " 'have a conception is an eternal world without any beginning or ending',\n",
       " 'in which all thing are ordered by rule supported by a divine',\n",
       " 'providence and that the heavenly body do not move by chance nor by',\n",
       " 'their own will but by the determinate will and appointment of the',\n",
       " 'god They recorded these movement but mainly in the hope of tracing',\n",
       " 'the will of the god in mundane affair Ptolemy about',\n",
       " 'made use of Babylonian eclipse in the eighth century for',\n",
       " 'improving his solar and lunar table',\n",
       " 'Fragments of a library at Agade have been preserved at Nineveh from',\n",
       " 'which we learn that the were even then divided into',\n",
       " 'constellation which were known by the name which they bear to this',\n",
       " 'day and that the sign of the zodiac were used for determining the',\n",
       " 'course of the sun moon and of the five planet Mercury Venus',\n",
       " 'Mars Jupiter and Saturn',\n",
       " 'We have record of observation carried on under Asshurbanapal who',\n",
       " 'sent astronomer to different part to study celestial phenomenon Here',\n",
       " 'is one',\n",
       " 'To the Director of Observations My Lord his humble servant',\n",
       " 'Great Astronomer of Nineveh writes thus May Nabu',\n",
       " 'and Marduk be propitious to the Director of these Observations my',\n",
       " 'Lord The fifteenth day we observed the Node of the moon and the moon',\n",
       " 'wa eclipsed',\n",
       " 'The Phoenicians are supposed to have used the star for navigation',\n",
       " 'but there are no record The Egyptian priest tried to keep such',\n",
       " 'astronomical knowledge a they possessed to themselves It is probable',\n",
       " 'that they had arbitrary rule for predicting eclipse All that wa',\n",
       " 'known to the Greeks about Egyptian science is to be found in the',\n",
       " 'writing of Diodorus Siculus But confirmatory and more authentic',\n",
       " 'fact have been derived from late exploration Thus we learn from',\n",
       " 'Knobel about the Jewish calendar date on record of land',\n",
       " 'sale in Aramaic papyrus at Assuan translated by Professor Sayce',\n",
       " 'and Cowley that the lunar cycle of nineteen year wa used',\n",
       " 'by the Jews in the fifth century the present reformed Jewish',\n",
       " 'calendar dating from the fourth century a date a little more',\n",
       " 'than a century after the grandfather and of those',\n",
       " 'whose business is recorded had fled into Egypt with Jeremiah Sayce',\n",
       " 'and that the order of intercalation at that time wa not',\n",
       " 'dissimilar to that in use at the present day',\n",
       " 'Then again Knobel reminds u of the most interesting discovery a few',\n",
       " 'year ago by Father Strassmeier of a Babylonian tablet recording a',\n",
       " 'partial lunar eclipse at Babylon in the seventh year of Cambyses on',\n",
       " 'the fourteenth day of the Jewish month Tammuz Ptolemy in the',\n",
       " 'Almagest Suntaxis say it occurred in the seventh year of Cambyses',\n",
       " 'on the night of the seventeenth and eighteenth of the Egyptian month',\n",
       " 'Phamenoth Pingré and Oppolzer fix the date July Thus',\n",
       " 'are the relation of the chronology of Jews and Egyptians',\n",
       " 'established by these exploration',\n",
       " 'FOOTNOTES',\n",
       " 'These ancient date are uncertain',\n",
       " 'Monthly vol No March',\n",
       " 'ANCIENT GREEK ASTRONOMY',\n",
       " 'We have our information about the earliest Greek astronomy from',\n",
       " 'Herodotus born He put the tradition into writing Thales',\n",
       " 'is said to have predicted an eclipse which caused much',\n",
       " 'alarm and ended the battle between the Medes and Lydians Airy fixed',\n",
       " 'the date May But other modern astronomer give',\n",
       " 'different date Thales went to Egypt to study science and learnt',\n",
       " 'from it priest the length of the year which wa kept a profound',\n",
       " 'secret and the sign of the zodiac and the position of the',\n",
       " 'solstice He held that the sun moon and star are not mere spot on',\n",
       " 'the heavenly vault but solid that the moon derives her light from',\n",
       " 'the sun and that this fact explains her phase that an eclipse of',\n",
       " 'the moon happens when the earth cut off the sun light from her He',\n",
       " 'supposed the earth to be flat and to float upon water He determined',\n",
       " 'the ratio of the sun diameter to it orbit and apparently made out',\n",
       " 'the diameter correctly a half a degree He left nothing in writing',\n",
       " 'His successor Anaximander and Anaximenes',\n",
       " 'held absurd notion about the sun moon and star while',\n",
       " 'Heraclitus supposed that the star were lighted each',\n",
       " 'night like lamp and the sun each morning Parmenides supposed the',\n",
       " 'earth to be a sphere',\n",
       " 'Pythagoras visited Egypt to study science He deduced',\n",
       " 'his system in which the earth revolves in an orbit from fantastic',\n",
       " 'first principle of which the following are example The circular',\n",
       " 'motion is the most perfect motion Fire is more worthy than earth',\n",
       " 'Ten is the perfect number He wrote nothing but is supposed to have',\n",
       " 'said that the earth moon five planet and fixed star all revolve',\n",
       " 'round the sun which itself revolves round an imaginary central fire',\n",
       " 'called the Antichthon Copernicus in the sixteenth century claimed',\n",
       " 'Pythagoras a the founder of the system which he Copernicus revived',\n",
       " 'Anaxagoras born studied astronomy in Egypt He explained',\n",
       " 'the return of the sun to the east each morning by it going under the',\n",
       " 'flat earth in the night He held that in a solar eclipse the moon',\n",
       " 'hide the sun and in a lunar eclipse the moon enters the earth',\n",
       " 'shadow both excellent opinion But he entertained absurd idea of',\n",
       " 'the vortical motion of the heaven whisking stone into the sky there',\n",
       " 'to be ignited by the fiery firmament to form star He wa prosecuted',\n",
       " 'for this unsettling opinion and for maintaining that the moon is an',\n",
       " 'inhabited earth He wa defended by Pericles',\n",
       " 'Solon dabbled like many others in reform of the calendar The',\n",
       " 'common year of the Greeks originally had day twelve month of',\n",
       " 'thirty day Solon year wa day It is obvious that these',\n",
       " 'erroneous year would before long remove the summer to January and',\n",
       " 'the winter to July To prevent this it wa customary at regular',\n",
       " 'interval to intercalate day or month Meton introduced a',\n",
       " 'reform based on the cycle This is not the same a the',\n",
       " 'Egyptian and Chaldean eclipse cycle called of',\n",
       " 'lunation or a little over eighteen year The Metonic cycle is',\n",
       " 'lunation or nineteen year after which period the sun and moon',\n",
       " 'occupy the same position relative to the star It is still used for',\n",
       " 'fixing the date of Easter the number of the year in Melon cycle',\n",
       " 'being the golden number of our Melon system divided',\n",
       " 'the lunation into month of thirty day and omitted every',\n",
       " 'day Of the nineteen year twelve had twelve month and',\n",
       " 'seven had thirteen month',\n",
       " 'Callippus used a cycle four time a long lunation',\n",
       " 'but one day short of Melon year This wa more correct',\n",
       " 'Eudoxus is said to have travelled with Plato in',\n",
       " 'Egypt He made astronomical observation in Asia Minor Sicily and',\n",
       " 'Italy and described the starry heaven divided into constellation',\n",
       " 'His name is connected with a planetary theory which a generally',\n",
       " 'stated sound most fanciful He imagined the fixed star to be on a',\n",
       " 'vault of heaven and the sun moon and planet to be upon similar',\n",
       " 'vault or sphere revolving sphere in all the motion of',\n",
       " 'each planet being resolved into it component and a separate sphere',\n",
       " 'being assigned for each component motion Callippus',\n",
       " 'increased the number to It is now generally accepted',\n",
       " 'that the real existence of these sphere wa not suggested but the',\n",
       " 'idea wa only a mathematical conception to facilitate the construction',\n",
       " 'of table for predicting the place of the heavenly body',\n",
       " 'Aristotle summed up the state of astronomical knowledge',\n",
       " 'in his time and held the earth to be fixed in the centre of the',\n",
       " 'world',\n",
       " 'Nicetas Heraclides and Ecphantes supposed the earth to revolve on',\n",
       " 'it axis but to have no orbital motion',\n",
       " 'The short epitome so far given illustrates the extraordinary deductive',\n",
       " 'method adopted by the ancient Greeks But they went much farther in',\n",
       " 'the same direction They seem to have been in great difficulty to',\n",
       " 'explain how the earth is supported just a were those who invented',\n",
       " 'the myth of Atlas or the Indians with the tortoise Thales thought',\n",
       " 'that the flat earth floated on water Anaxagoras thought that being',\n",
       " 'flat it would be buoyed up and supported on the air like a kite',\n",
       " 'Democritus thought it remained fixed like the donkey between two',\n",
       " 'bundle of hay because it wa equidistant from all part of the',\n",
       " 'containing sphere and there wa no reason why it should incline one',\n",
       " 'way rather than another Empedocles attributed it state of rest to',\n",
       " 'centrifugal force by the rapid circular movement of the heaven a',\n",
       " 'water is stationary in a pail when whirled round by a string',\n",
       " 'Democritus further supposed that the inclination of the flat earth to',\n",
       " 'the ecliptic wa due to the greater weight of the southern part owing',\n",
       " 'to the exuberant vegetation',\n",
       " 'For further reference to similar effort of imagination the reader is',\n",
       " 'referred to Sir George Cornwall Lewis Survey of the',\n",
       " 'Astronomy of the London His list of authority',\n",
       " 'is very complete but some of his conclusion are doubtful At',\n",
       " 'of that work he record the real opinion of Socrates a set forth by',\n",
       " 'Xenophon and the reader will perhaps sympathise with Socrates in',\n",
       " 'his view on contemporary astronomy',\n",
       " 'With regard to astronomy he Socrates considered a knowledge of it',\n",
       " 'desirable to the extent of determining the day of the year or month',\n",
       " 'and the hour of the night but a to learning the course of the',\n",
       " 'star to be occupied with the planet and to inquire about their',\n",
       " 'distance from the earth and their orbit and the cause of their',\n",
       " 'motion he strongly objected to such a waste of valuable time He',\n",
       " 'dwelt on the contradiction and conflicting opinion of the physical',\n",
       " 'philosopher and in fine he held that the speculator on the',\n",
       " 'universe and on the law of the heavenly body were no better than',\n",
       " 'madman i',\n",
       " 'Plato born the pupil of Socrates the of',\n",
       " 'Euclid and a follower of Pythagoras studied science in his travel',\n",
       " 'in Egypt and elsewhere He wa held in so great reverence by all',\n",
       " 'learned men that a problem which he set to the astronomer wa the',\n",
       " 'keynote to all astronomical investigation from this date till the time',\n",
       " 'of Kepler in the sixteenth century He proposed to astronomer',\n",
       " 'problem of representing the course of the planet by circular and',\n",
       " 'uniform',\n",
       " 'Systematic observation among the Greeks began with the rise of the',\n",
       " 'Alexandrian school Aristillus and Timocharis set up instrument and',\n",
       " 'fixed the position of the zodiacal star near to which all the',\n",
       " 'planet in their orbit pas thus facilitating the determination of',\n",
       " 'planetary motion Aristarchus showed that the sun must',\n",
       " 'be at least nineteen time a far off a the moon which is far short',\n",
       " 'of the mark He also found the sun diameter correctly to be half a',\n",
       " 'degree Eratosthenes measured the inclination to the',\n",
       " 'equator of the sun apparent path in the heaven he',\n",
       " 'measured the obliquity of the ecliptic making it confirming',\n",
       " 'our knowledge of it continuous diminution during historical time He',\n",
       " 'measured an arc of meridian from Alexandria to Syene Assuan and',\n",
       " 'found the difference of latitude by the length of a shadow at noon',\n",
       " 'summer solstice He deduced the diameter of the earth',\n",
       " 'stadium Unfortunately we do not know the length of the stadium he',\n",
       " 'used',\n",
       " 'Hipparchus may be regarded a the founder of',\n",
       " 'observational astronomy He measured the obliquity of the ecliptic',\n",
       " 'and agreed with Eratosthenes He altered the length of the tropical',\n",
       " 'year from day hour to day hour minute still',\n",
       " 'four minute too much He measured the equation of time and the',\n",
       " 'irregular motion of the sun and allowed for this in his calculation',\n",
       " 'by supposing that the centre about which the sun move uniformly is',\n",
       " 'situated a little distance from the fixed earth He called this point',\n",
       " 'the The line from the earth to the excentric wa',\n",
       " 'called the of A circle having this centre wa',\n",
       " 'called the and he supposed that a radius drawn to the',\n",
       " 'sun from the excentric pass over equal arc on the equant in equal',\n",
       " 'time He then computed table for predicting the place of the sun',\n",
       " 'He proceeded in the same way to compute Lunar table Making use of',\n",
       " 'Chaldæan eclipse he wa able to get an accurate value of the moon',\n",
       " 'mean motion Halley in compared this value with his own',\n",
       " 'measurement and so discovered the acceleration of the moon mean',\n",
       " 'motion This wa conclusively established but could not be explained',\n",
       " 'by the Newtonian theory for quite a long time He determined the',\n",
       " 'plane of the moon orbit and it inclination to the ecliptic The',\n",
       " 'motion of this plane round the pole of the ecliptic once in eighteen',\n",
       " 'year complicated the problem He located the moon excentric a he',\n",
       " 'had done the sun He also discovered some of the minor',\n",
       " 'irregularity of the moon motion due a Newton theory prof',\n",
       " 'to the disturbing action of the sun attraction',\n",
       " 'In the year Hipparchus observed a new star This upset every',\n",
       " 'notion about the permanence of the fixed star He then set to work to',\n",
       " 'catalogue all the principal star so a to know if any others appeared',\n",
       " 'or disappeared Here his experience resembled those of several later',\n",
       " 'astronomer who when in search of some special object have been',\n",
       " 'rewarded by a discovery in a totally different direction On comparing',\n",
       " 'his star position with those of Timocharis and Aristillus he found no',\n",
       " 'star that had appeared or disappeared in the interval of year',\n",
       " 'but he found that all the star seemed to have changed their place',\n",
       " 'with reference to that point in the heaven where the ecliptic is',\n",
       " 'from the pole of the earth the equinox He found that this',\n",
       " 'could be explained by a motion of the equinox in the direction of the',\n",
       " 'apparent diurnal motion of the star This discovery of of',\n",
       " 'the which take place at the rate of every year wa',\n",
       " 'necessary for the progress of accurate astronomical observation It',\n",
       " 'is due to a steady revolution of the earth pole round the pole of',\n",
       " 'the ecliptic once in year in the opposite direction to the',\n",
       " 'planetary revolution',\n",
       " 'Hipparchus wa also the inventor of trigonometry both plane and',\n",
       " 'spherical He explained the method of using eclipse for determining',\n",
       " 'the longitude',\n",
       " 'In connection with Hipparchus great discovery it may be mentioned',\n",
       " 'that modern astronomer have often attempted to fix date in history',\n",
       " 'by the effect of precession of the equinox At about the date',\n",
       " 'when the Great Pyramid may have been built γDraconis wa near to the',\n",
       " 'pole and must have been used a the In the north face of',\n",
       " 'the Great Pyramid is the entrance to an inclined passage and six of',\n",
       " 'the nine pyramid at Gizeh posse the same feature all the passage',\n",
       " 'being inclined at an angle between and to the horizon and in',\n",
       " 'the plane of the meridian It also appears that year',\n",
       " 'ago about an observer at the lower end of the',\n",
       " 'passage would be able to see γDraconis the then at it',\n",
       " 'lower culmination It ha been suggested that the passage wa made',\n",
       " 'for this purpose On other ground the date assigned to the Great',\n",
       " 'Pyramid is',\n",
       " 'The Chaldæans gave name to constellation now invisible from',\n",
       " 'Babylon which would have been visible in at which date it',\n",
       " 'is claimed that these people were studying astronomy',\n",
       " 'In the Odyssey Calypso directs Odysseus in accordance with',\n",
       " 'Phoenician rule for navigating the Mediterranean to keep the Great',\n",
       " 'Bear ever on the left a he traversed the deep when sailing from the',\n",
       " 'pillar of Hercules Gibraltar to Corfu Yet such a course taken now',\n",
       " 'would land the traveller in Africa Odysseus is said in his voyage in',\n",
       " 'springtime to have seen the Pleiades and Arcturus setting late which',\n",
       " 'seemed to early commentator a proof of Homer inaccuracy Likewise',\n",
       " 'Homer both in the and in the',\n",
       " 'xviii asserts that the Great Bear never set in those',\n",
       " 'latitude Now it ha been found that the precession of the equinox',\n",
       " 'explains all these puzzle show that in springtime on the',\n",
       " 'Mediterranean the Bear wa just above the horizon near the sea but',\n",
       " 'not touching it between and and fix the date of',\n",
       " 'the poem thus confirming other evidence and establishing Homer',\n",
       " 'character for accuracy',\n",
       " 'The orientation of Egyptian temple and Druidical stone is such',\n",
       " 'that possibly they were so placed a to assist in the observation of',\n",
       " 'the heliacal rising of certain star If the star were known',\n",
       " 'this would give an approximate date Up to the present the result of',\n",
       " 'these investigation are far from being conclusive',\n",
       " 'Ptolemy wrote the Suntaxis or Almagest which includes a',\n",
       " 'cyclopedia of astronomy containing a summary of knowledge at that',\n",
       " 'date We have no evidence beyond his own statement that he wa a',\n",
       " 'practical observer He theorised on the planetary motion and held',\n",
       " 'that the earth is fixed in the centre of the universe He adopted the',\n",
       " 'excentric and equant of Hipparchus to explain the unequal motion of',\n",
       " 'the sun and moon He adopted the epicycle and deferents which had',\n",
       " 'been used by Apollonius and others to explain the retrograde motion',\n",
       " 'of the planet We who know that the earth revolves round the sun',\n",
       " 'once in a year can understand that the apparent motion of a planet is',\n",
       " 'only it motion relative to the earth If then we suppose the earth',\n",
       " 'fixed and the sun to revolve round it once a year and the planet',\n",
       " 'each in it own period it is only necessary to impose upon each of',\n",
       " 'these an additional motion to enable u to represent truly',\n",
       " 'the apparent motion This way of looking at the apparent motion',\n",
       " 'show why each planet when nearest to the earth seems to move for a',\n",
       " 'time in a retrograde direction The attempt of Ptolemy and others of',\n",
       " 'his time to explain the retrograde motion in this way were only',\n",
       " 'approximate Let u suppose each planet to have a bar with one end',\n",
       " 'centred at the earth If at the other end of the bar one end of a',\n",
       " 'shorter bar is pivotted having the planet at it other end then the',\n",
       " 'planet is given an annual motion in the secondary circle the',\n",
       " 'epicycle whose centre revolves round the earth on the primary circle',\n",
       " 'the at a uniform rate round the excentric Ptolemy',\n",
       " 'supposed the centre of the epicycle of Mercury and Venus to be on a',\n",
       " 'bar passing through the sun and to be between the earth and the',\n",
       " 'sun The centre of the epicycle of Mars Jupiter and Saturn were',\n",
       " 'supposed to be further away than the sun Mercury and Venus were',\n",
       " 'supposed to revolve in their epicycle in their own periodic time and',\n",
       " 'in the deferent round the earth in a year The major planet were',\n",
       " 'supposed to revolve in the deferent round the earth in their own',\n",
       " 'periodic time and in their epicycle once in a year',\n",
       " 'It did not occur to Ptolemy to place the centre of the epicycle of',\n",
       " 'Mercury and Venus at the sun and to extend the same system to the',\n",
       " 'major planet Something of this sort had been proposed by the',\n",
       " 'Egyptians we are told by Cicero and others and wa accepted by',\n",
       " 'Tycho Brahe and wa a true a representation of the relative motion',\n",
       " 'in the solar system a when we suppose the sun to be fixed and the',\n",
       " 'earth to revolve',\n",
       " 'The cumbrous system advocated by Ptolemy answered it purpose',\n",
       " 'enabling him to predict astronomical event approximately He improved',\n",
       " 'the lunar theory considerably and discovered minor inequality which',\n",
       " 'could be allowed for by the addition of new epicycle We may look',\n",
       " 'upon these epicycle of Apollonius and the excentric of Hipparchus',\n",
       " 'a the response of these astronomer to the demand of Plato for',\n",
       " 'uniform circular motion Their use became more and more confirmed',\n",
       " 'until the seventeenth century when the accurate observation of Tycho',\n",
       " 'Brahe enabled Kepler to abolish these purely geometrical makeshift',\n",
       " 'and to substitute a system in which the sun became physically it',\n",
       " 'controller',\n",
       " 'FOOTNOTES',\n",
       " 'vol pp',\n",
       " '',\n",
       " 'Πληιάδας τʽ δύοντα βοώτην',\n",
       " 'ʼΆρκτον καλέουσιν',\n",
       " 'ʽΉ στρέφεται ʼΩρίωνα δοκεύει',\n",
       " 'λοετρων',\n",
       " 'The Pleiades and Boötes that setteth late and the Bear',\n",
       " 'which they likewise call the Wain which turneth ever in one',\n",
       " 'place and keepeth watch upon Orion and alone hath no part in',\n",
       " 'the bath of the ocean',\n",
       " 'See Pearson in the Camb Phil Soc vol pt p',\n",
       " 'on whose authority the above statement are made',\n",
       " 'See for definition',\n",
       " 'THE REIGN OF EPICYCLES FROM PTOLEMY TO COPERNICUS',\n",
       " 'After Ptolemy had published his book there seemed to be nothing more',\n",
       " 'to do for the solar system except to go on observing and finding more',\n",
       " 'and more accurate value for the constant involved the period',\n",
       " 'of revolution the diameter of the deferent and it ratio to that',\n",
       " 'of the epicycle the distance of the excentric from the centre',\n",
       " 'of the deferent and the position of the line of apse besides the',\n",
       " 'inclination and position of the plane of the planet orbit The only',\n",
       " 'object ever aimed at in those day wa to prepare table for',\n",
       " 'predicting the place of the planet It wa not a mechanical problem',\n",
       " 'there wa no notion of a governing law of force',\n",
       " 'From this time onwards all interest in astronomy seemed in Europe at',\n",
       " 'least to sink to a low ebb When the Caliph Omar in the middle of',\n",
       " 'the seventh century burnt the library of Alexandria which had been',\n",
       " 'the centre of intellectual progress that centre migrated to Baghdad',\n",
       " 'and the Arabs became the leader of science and philosophy In',\n",
       " 'astronomy they made careful observation In the middle of the ninth',\n",
       " 'century Albategnius a Syrian prince improved the value of',\n",
       " 'excentricity of the sun orbit observed the motion of the moon',\n",
       " 'apse and thought he detected a smaller progression of the sun',\n",
       " 'apse His table were much more accurate than Ptolemy Abul Wefa in',\n",
       " 'the tenth century seems to have discovered the moon variation',\n",
       " 'Meanwhile the Moors were leader of science in the west and Arzachel',\n",
       " 'of Toledo improved the solar table very much Ulugh Begh grandson of',\n",
       " 'the great Tamerlane the Tartar built a fine observatory at Samarcand',\n",
       " 'in the fifteenth century and made a great catalogue of star the',\n",
       " 'first since the time of Hipparchus',\n",
       " 'At the close of the fifteenth century King Alphonso of Spain employed',\n",
       " 'computer to produce the Alphonsine Tables Purbach',\n",
       " 'translated Ptolemy book and observation were carried out in',\n",
       " 'Germany by Müller known a Regiomontanus and Waltherus',\n",
       " 'Nicolai Copernicus a Sclav wa born in at Thorn in Polish',\n",
       " 'Prussia He studied at Cracow and in Italy He wa a priest and',\n",
       " 'settled at Frauenberg He did not undertake continuous observation',\n",
       " 'but devoted himself to simplifying the planetary system and devising',\n",
       " 'mean for more accurately predicting the position of the sun moon',\n",
       " 'and planet He had no idea of framing a solar system on a dynamical',\n",
       " 'basis His great object wa to increase the accuracy of the',\n",
       " 'calculation and the table The result of his cogitation were',\n",
       " 'printed just before his death in an interesting book',\n",
       " 'Revolutionibus Orbium It is only by careful reading of',\n",
       " 'this book that the true position of Copernicus can be realised He',\n",
       " 'noticed that Nicetas and others had ascribed the apparent diurnal',\n",
       " 'rotation of the heaven to a real daily rotation of the earth about',\n",
       " 'it axis in the opposite direction to the apparent motion of the',\n",
       " 'star Also in the writing of Martianus Capella he learnt that the',\n",
       " 'Egyptians had supposed Mercury and Venus to revolve round the sun and',\n",
       " 'to be carried with him in his annual motion round the earth He',\n",
       " 'noticed that the same supposition if extended to Mars Jupiter and',\n",
       " 'Saturn would explain easily why they and especially Mars seem so',\n",
       " 'much brighter in opposition For Mars would then be a great deal',\n",
       " 'nearer to the earth than at other time It would also explain the',\n",
       " 'retrograde motion of planet when in opposition',\n",
       " 'We must here notice that at this stage Copernicus wa actually',\n",
       " 'confronted with the system accepted later by Tycho Brahe with the',\n",
       " 'earth fixed But he now recalled and accepted the view of Pythagoras',\n",
       " 'and others according to which the sun is fixed and the earth',\n",
       " 'revolves and it must be noted that geometrically there is no',\n",
       " 'difference of any sort between the Egyptian or Tychonic system and',\n",
       " 'that of Pythagoras a revived by Copernicus except that on the latter',\n",
       " 'theory the star ought to seem to move when the earth change it',\n",
       " 'position a test which failed completely with the rough mean of',\n",
       " 'observation then available The radical defect of all solar system',\n",
       " 'previous to the time of Kepler wa the slavish yielding to',\n",
       " 'Plato dictum demanding uniform circular motion for the planet and',\n",
       " 'the consequent evolution of the epicycle which wa fatal to any',\n",
       " 'conception of a dynamical theory',\n",
       " 'Copernicus could not sever himself from this obnoxious tradition',\n",
       " 'It is true that neither the Pythagorean nor the system',\n",
       " 'required epicycle for explaining retrograde motion a the Ptolemaic',\n",
       " 'theory did Furthermore either system could use the excentric of',\n",
       " 'Hipparchus to explain the irregular motion known a the equation of',\n",
       " 'the centre But Copernicus remarked that he could also use an',\n",
       " 'epicycle for this purpose or that he could use both an excentric and',\n",
       " 'an epicycle for each planet and so bring theory still closer into',\n",
       " 'accord with observation And this he proceeded to do Moreover',\n",
       " 'observer had found irregularity in the moon motion due a we',\n",
       " 'now know to the disturbing attraction of the sun To correct for',\n",
       " 'these irregularity Copernicus introduced epicycle on epicycle in the',\n",
       " 'lunar orbit',\n",
       " 'This is in it main feature the system propounded by Copernicus But',\n",
       " 'attention must to state the case fully be drawn to two point to be',\n",
       " 'found in his first and sixth book respectively The first point',\n",
       " 'relates to the season and it show a strange ignorance of the law',\n",
       " 'of rotating body To use the word of Delambre in drawing',\n",
       " 'attention to the strange conception',\n",
       " 'he imagined that the earth revolving round the sun ought always to',\n",
       " 'show to it the same face the contrary phenomenon surprised him to',\n",
       " 'explain them he invented a third motion and added it to the two',\n",
       " 'real motion rotation and orbital revolution By this third motion',\n",
       " 'the earth he held made a revolution on itself and on the pole of',\n",
       " 'the ecliptic once a year Copernicus did not know that motion in',\n",
       " 'a straight line is the natural motion and that motion in a curve is',\n",
       " 'the resultant of several movement He believed with Aristotle',\n",
       " 'that circular motion wa the natural one',\n",
       " 'Copernicus made this rotation of the earth axis about the pole of',\n",
       " 'the ecliptic retrograde opposite to the orbital revolution',\n",
       " 'and by making it perform more than one complete revolution in a year',\n",
       " 'the added part being of the whole he wa able to include the',\n",
       " 'precession of the equinox in his explanation of the season His',\n",
       " 'explanation of the season is given on leaf of his book the page',\n",
       " 'of this book are not all numbered only alternate page or leaf',\n",
       " 'In his sixth book he discus the inclination of the planetary orbit',\n",
       " 'to the ecliptic In regard to this the theory of Copernicus is unique',\n",
       " 'and it will be best to explain this in the word of Grant in his great',\n",
       " 'work He say',\n",
       " 'Copernicus a we have already remarked did not attack the',\n",
       " 'principle of the epicyclical theory he merely sought to make it',\n",
       " 'more simple by placing the centre of the earth orbit in the centre',\n",
       " 'of the universe This wa the point to which the motion of the',\n",
       " 'planet were referred for the plane of their orbit were made to',\n",
       " 'pas through it and their point of least and greatest velocity',\n",
       " 'were also determined with reference to it By this arrangement the',\n",
       " 'sun wa situate mathematically near the centre of the planetary',\n",
       " 'system but he did not appear to have any physical connexion with',\n",
       " 'the planet a the centre of their motion',\n",
       " 'According to Copernicus sixth book the plane of the planetary',\n",
       " 'orbit do not pas through the sun and the line of apse do not pas',\n",
       " 'through to the sun',\n",
       " 'Such wa the theory advanced by Copernicus The earth move in an',\n",
       " 'epicycle on a deferent whose centre is a little distance from the',\n",
       " 'sun The planet move in a similar way on epicycle but their',\n",
       " 'deferents have no geometrical or physical relation to the sun The',\n",
       " 'moon move on an epicycle centred on a second epicycle itself centred',\n",
       " 'on a deferent excentric to the earth The earth axis rotates about',\n",
       " 'the pole of the ecliptic making one revolution and a',\n",
       " 'thousandth part of a revolution in the sidereal year in the opposite',\n",
       " 'direction to it orbital motion',\n",
       " 'In view of this fanciful structure it must be noted in fairness to',\n",
       " 'Copernicus that he repeatedly state that the reader is not obliged',\n",
       " 'to accept his system a showing the real motion that it doe not',\n",
       " 'matter whether they be true even approximately or not so long a',\n",
       " 'they enable u to compute table from which the place of the planet',\n",
       " 'among the star can be predicted He say that whoever is not',\n",
       " 'satisfied with this explanation must be contented by being told that',\n",
       " 'mathematics are for mathematician Mathematicis mathematica',\n",
       " 'scribuntur',\n",
       " 'At the same time he express his conviction over and over again that',\n",
       " 'the earth is in motion It is with him a pious belief just a it wa',\n",
       " 'with Pythagoras and his school and with Aristarchus But a Dreyer',\n",
       " 'say in his most interesting book proof of the',\n",
       " 'physical truth of his system Copernicus had given none and could give',\n",
       " 'none any more than Pythagoras or Aristarchus',\n",
       " 'There wa nothing so startlingly simple in his system a to lead the',\n",
       " 'cautious astronomer to accept it a there wa in the later Keplerian',\n",
       " 'system and the absence of parallax in the star seemed to condemn his',\n",
       " 'system which had no physical basis to recommend it and no',\n",
       " 'simplification at all over the system to which',\n",
       " 'Copernicus himself drew attention It ha been necessary to devote',\n",
       " 'perhaps undue space to the interesting work of Copernicus because by',\n",
       " 'a curious chance his name ha become so widely known He ha been',\n",
       " 'spoken of very generally a the founder of the solar system that is',\n",
       " 'now accepted This seems unfair and on reading over what ha been',\n",
       " 'written about him at different time it will be noticed that the',\n",
       " 'astronomer those who have evidently read his great book are very',\n",
       " 'cautious in the word with which they eulogise him and refrain from',\n",
       " 'attributing to him the foundation of our solar system which is',\n",
       " 'entirely due to Kepler It is only the more popular writer who give',\n",
       " 'the idea that a revolution had been effected when Pythagoras system',\n",
       " 'wa revived and when Copernicus supported his view that the earth',\n",
       " 'move and is not fixed',\n",
       " 'It may be easy to explain the association of the name of Copernicus',\n",
       " 'with the Keplerian system But the time ha long passed when the',\n",
       " 'historian can support in any way this popular error which wa started',\n",
       " 'not by astronomer acquainted with Kepler work but by those who',\n",
       " 'desired to put the Church in the wrong by extolling Copernicus',\n",
       " 'Copernicus dreaded much the abuse he expected to receive from',\n",
       " 'philosopher for opposing the authority of Aristotle who had declared',\n",
       " 'that the earth wa fixed So he sought and obtained the support of',\n",
       " 'the Church dedicating his great work to Pope Paul III in a lengthy',\n",
       " 'explanatory epistle The Bishop of Cracow set up a memorial tablet in',\n",
       " 'his honour',\n",
       " 'Copernicus wa the most refined exponent and almost the last',\n",
       " 'representative of the Epicyclical School As ha been already',\n",
       " 'stated his successor Tycho Brahe supported the same use of',\n",
       " 'epicycle and excentrics a Copernicus though he held the earth to be',\n",
       " 'fixed But Tycho Brahe wa eminently a practical observer and took',\n",
       " 'little part in theory and his observation formed so essential a',\n",
       " 'portion of the system of Kepler that it is only fair to include his',\n",
       " 'name among these who laid the foundation of the solar system which we',\n",
       " 'accept',\n",
       " 'In now taking leave of the system of epicycle let it be remarked that',\n",
       " 'it ha been held up to ridicule more than it deserves On reading',\n",
       " 'Airy account of epicycle in the beautifully clear language of his',\n",
       " 'Lectures on the impression is made that the',\n",
       " 'jointed bar there spoken of for describing the circle were supposed',\n",
       " 'to be real This is no more the case than that the sphere of Eudoxus',\n",
       " 'and Callippus were supposed to be real Both were introduced only to',\n",
       " 'illustrate the mathematical conception upon which the solar',\n",
       " 'planetary and lunar table were constructed The epicycle',\n",
       " 'represented nothing more nor le than the first term in the Fourier',\n",
       " 'series which in the last century ha become a basis of such',\n",
       " 'calculation both in astronomy and physic generally',\n",
       " 'Illustration QUADRANS MURALIS SIVE TICHONICUS With portrait of',\n",
       " 'Tycho Brahe instrument painted on the wall showing',\n",
       " 'assistant using the sight watching the clock and recording From',\n",
       " 'the author copy of the Instauratæ',\n",
       " 'FOOTNOTES',\n",
       " 'For definition see',\n",
       " '',\n",
       " 'For definition see',\n",
       " 'For definition see',\n",
       " 'In his great book Copernicus say The movement of the heavenly',\n",
       " 'body is uniform circular perpetual or else composed of circular',\n",
       " 'movement In this he proclaimed himself a follower of Pythagoras',\n",
       " 'see a also when he say The world is spherical because the',\n",
       " 'sphere is of all figure the most perfect Delambre',\n",
       " 'Mod pp',\n",
       " 'Kepler tell u that Tycho Brahe wa pleased with this',\n",
       " 'device and adapted it to his own system',\n",
       " 'vol',\n",
       " 'of Phys vii',\n",
       " 'Est enim Astronomi proprium historiam motuum coelestium',\n",
       " 'diligenti et artificiosa observatione colligere Deinde causa',\n",
       " 'earundem seu hypothesis cum veras assequi nulla ratione possit',\n",
       " 'Neque enim necesse est ea hypothesis esse veras imo ne',\n",
       " 'verisimiles quidem sed sufficit hoc usum si calculum observationibus',\n",
       " 'congruentem exhibeant',\n",
       " 'BOOK II THE DYNAMICAL PERIOD',\n",
       " 'DISCOVERY OF THE TRUE SOLAR SYSTEM TYCHO BRAHE KEPLER',\n",
       " 'During the period of the intellectual and aesthetic revival at the',\n",
       " 'beginning of the sixteenth century the spirit of the age wa',\n",
       " 'fostered by the invention of printing by the downfall of the',\n",
       " 'Byzantine Empire and the scattering of Greek fugitive carrying the',\n",
       " 'treasure of literature through Western Europe by the work of',\n",
       " 'Raphael and Michael Angelo by the Reformation and by the extension',\n",
       " 'of the known world through the voyage of Spaniards and Portuguese',\n",
       " 'During that period there came to the front the founder of accurate',\n",
       " 'observational astronomy Tycho Brahe a Dane born in of noble',\n",
       " 'parent wa the most distinguished diligent and accurate observer',\n",
       " 'of the heaven since the day of Hipparchus year before',\n",
       " 'Tycho wa devoted entirely to his science from childhood and the',\n",
       " 'opposition of his parent only stimulated him in his effort to',\n",
       " 'overcome difficulty He soon grasped the hopelessness of the old',\n",
       " 'deductive method of reasoning and decided that no theory ought to',\n",
       " 'be indulged in until preparation had been made by the accumulation of',\n",
       " 'accurate observation We may claim for him the title of founder of',\n",
       " 'the inductive method',\n",
       " 'For a complete life of this great man the reader is referred to',\n",
       " 'Dreyer Edinburgh containing a complete',\n",
       " 'bibliography The present notice must be limited to noting the work',\n",
       " 'done and the quality of character which enabled him to attain his',\n",
       " 'scientific aim and which have been conspicuous in many of his',\n",
       " 'successor',\n",
       " 'He studied in Germany but King Frederick of Denmark appreciating his',\n",
       " 'great talent invited him to carry out his life work in that',\n",
       " 'country He granted to him the island of Hveen gave him a pension',\n",
       " 'and made him a canon of the Cathedral of Roskilde On that island',\n",
       " 'Tycho Brahe built the splendid observatory which he called Uraniborg',\n",
       " 'and later a second one for his assistant and student called',\n",
       " 'Stjerneborg These he fitted up with the most perfect instrument and',\n",
       " 'never lost a chance of adding to his stock of careful observation',\n",
       " 'The account of all these instrument and observation printed at his',\n",
       " 'own press on the island wa published by Tycho Brahe himself and the',\n",
       " 'admirable and numerous engraving bear witness to the excellence of',\n",
       " 'design and the stability of his instrument',\n",
       " 'His mechanical skill wa very great and in his workmanship he wa',\n",
       " 'satisfied with nothing but the best He recognised the importance of',\n",
       " 'rigidity in the instrument and whereas these had generally been',\n",
       " 'made of wood he designed them in metal His instrument included',\n",
       " 'armillae like those which had been used in Alexandria and other',\n",
       " 'armillae designed by himself sextant mural quadrant large',\n",
       " 'celestial globe and various instrument for special purpose He',\n",
       " 'lived before the day of telescope and accurate clock He invented',\n",
       " 'the method of the degree on the arc of an instrument by',\n",
       " 'transversals somewhat in the way that Pedro Nunez had proposed',\n",
       " 'He originated the true system of observation and reduction of',\n",
       " 'observation recognising the fact that the best instrument in the',\n",
       " 'world is not perfect and with each of his instrument he set to work',\n",
       " 'to find out the error of graduation and the error of mounting the',\n",
       " 'necessary correction being applied to each observation',\n",
       " 'When he wanted to point his instrument exactly to a star he wa',\n",
       " 'confronted with precisely the same difficulty a is met in gunnery and',\n",
       " 'The sight and the object aimed at can not be in focus',\n",
       " 'together and a great deal depends on the form of sight Tycho Brahe',\n",
       " 'invented and applied to the pointer of his instrument an',\n",
       " 'of variable area like the iris diaphragm used now in',\n",
       " 'photography This enabled him to get the best result with star of',\n",
       " 'different brightness The telescope not having been invented he',\n",
       " 'could not use a a we now do in gunnery This not',\n",
       " 'only remove the difficulty of focussing but make the minimum',\n",
       " 'visible angle smaller Helmholtz ha defined the minimum angle',\n",
       " 'measurable with the naked eye a being one minute of arc In view of',\n",
       " 'this it is simply marvellous that when the position of Tycho',\n",
       " 'standard star are compared with the best modern catalogue his',\n",
       " 'probable error in right ascension is only and in declination',\n",
       " 'only',\n",
       " 'Clocks of a sort had been made but Tycho Brahe found them so',\n",
       " 'unreliable that he seldom used them and many of his',\n",
       " 'were made by measuring the angular distance from known star',\n",
       " 'Taking into consideration the absence of either a telescope or a',\n",
       " 'clock and reading his account of the labour he bestowed upon each',\n",
       " 'observation we must all agree that Kepler who inherited these',\n",
       " 'observation in wa justified under the condition then',\n",
       " ...]"
      ]
     },
     "execution_count": 8,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "corpus = [preprocessing(sentence) for sentence in corpus if sentence.strip() !='']\n",
    "corpus"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {},
   "outputs": [],
   "source": [
    "tokenizer = Tokenizer()\n",
    "tokenizer.fit_on_texts(corpus)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {},
   "outputs": [],
   "source": [
    "X_train_tokens = tokenizer.texts_to_sequences(corpus)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "4411"
      ]
     },
     "execution_count": 11,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "vocab_size = len(tokenizer.word_index) + 1\n",
    "vocab_size"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "metadata": {},
   "outputs": [],
   "source": [
    "items = tokenizer.word_index.items()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Creating the Skipgram Model:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "__________________________________________________________________________________________________\n",
      "Layer (type)                    Output Shape         Param #     Connected to                     \n",
      "==================================================================================================\n",
      "input_1 (InputLayer)            (None, 1)            0                                            \n",
      "__________________________________________________________________________________________________\n",
      "input_2 (InputLayer)            (None, 1)            0                                            \n",
      "__________________________________________________________________________________________________\n",
      "embedding_1 (Embedding)         (None, 1, 300)       1323300     input_1[0][0]                    \n",
      "__________________________________________________________________________________________________\n",
      "embedding_2 (Embedding)         (None, 1, 300)       1323300     input_2[0][0]                    \n",
      "__________________________________________________________________________________________________\n",
      "dot_1 (Dot)                     (None, 1, 1)         0           embedding_1[0][0]                \n",
      "                                                                 embedding_2[0][0]                \n",
      "__________________________________________________________________________________________________\n",
      "reshape_1 (Reshape)             (None, 1)            0           dot_1[0][0]                      \n",
      "__________________________________________________________________________________________________\n",
      "activation_1 (Activation)       (None, 1)            0           reshape_1[0][0]                  \n",
      "==================================================================================================\n",
      "Total params: 2,646,600\n",
      "Trainable params: 2,646,600\n",
      "Non-trainable params: 0\n",
      "__________________________________________________________________________________________________\n"
     ]
    }
   ],
   "source": [
    "dim_embedddings = 300\n",
    "\n",
    "# inputs\n",
    "inputs = Input(shape=(1, ), dtype='int32')\n",
    "w = Embedding(vocab_size, dim_embedddings)(inputs)\n",
    "\n",
    "# context\n",
    "c_inputs = Input(shape=(1, ), dtype='int32')\n",
    "c  = Embedding(vocab_size, dim_embedddings)(c_inputs)\n",
    "\n",
    "d = Dot(axes=2)([w, c])\n",
    "\n",
    "d = Reshape((1,), input_shape=(1, 1))(d)\n",
    "d = Activation('sigmoid')(d)\n",
    "\n",
    "model = Model(inputs=[inputs, c_inputs], outputs=d)\n",
    "model.summary()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 14,
   "metadata": {},
   "outputs": [],
   "source": [
    "model.compile(loss='binary_crossentropy', optimizer='adam')"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Training the model:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 15,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Epoch: 0 \tLoss: 1855.122561082244\n",
      "Epoch: 1 \tLoss: 1490.9883154407144\n",
      "Epoch: 2 \tLoss: 1388.3679221607745\n",
      "Epoch: 3 \tLoss: 1270.372354991734\n",
      "Epoch: 4 \tLoss: 1164.389208954759\n",
      "Epoch: 5 \tLoss: 1063.671567552723\n",
      "Epoch: 6 \tLoss: 982.9436835721135\n",
      "Epoch: 7 \tLoss: 913.5112223466858\n",
      "Epoch: 8 \tLoss: 857.7043578715529\n",
      "Epoch: 9 \tLoss: 809.6147848761175\n",
      "Epoch: 10 \tLoss: 771.9398003910901\n",
      "Epoch: 11 \tLoss: 743.7286821631715\n",
      "Epoch: 12 \tLoss: 722.955197765812\n",
      "Epoch: 13 \tLoss: 703.9326986923697\n",
      "Epoch: 14 \tLoss: 685.0070044388121\n",
      "Wall time: 4min 59s\n"
     ]
    }
   ],
   "source": [
    "%%time\n",
    "n_epochs = 15\n",
    "for epoch in range(n_epochs):\n",
    "    loss = 0.\n",
    "    for i, doc in enumerate(X_train_tokens):\n",
    "        data, labels = skipgrams(sequence=doc, vocabulary_size=vocab_size, window_size=4)\n",
    "        x = [np.array(x) for x in zip(*data)]\n",
    "        y = np.array(labels, dtype=np.int32)\n",
    "        if x:\n",
    "            loss += model.train_on_batch(x, y)\n",
    "\n",
    "    print('Epoch:', epoch, '\\tLoss:', loss)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Saving the model:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 18,
   "metadata": {},
   "outputs": [],
   "source": [
    "f = open('../data/word2vec-skipgrams1.txt' ,'w', encoding=\"utf8\")\n",
    "f.write('{} {}\\n'.format(vocab_size-1, dim_embedddings))\n",
    "\n",
    "weights = model.get_weights()[0]\n",
    "for word, i in items:\n",
    "    f.write('{} {}\\n'.format(word, ' '.join(map(str, list(weights[i, :])))))\n",
    "f.close()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Loading the model:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 19,
   "metadata": {},
   "outputs": [],
   "source": [
    "w2v = gensim.models.KeyedVectors.load_word2vec_format('../data/word2vec-skipgrams1.txt', binary=False)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 20,
   "metadata": {},
   "outputs": [
    {
     "name": "stderr",
     "output_type": "stream",
     "text": [
      "C:\\Anaconda36\\envs\\tf111_gpu\\lib\\site-packages\\gensim\\matutils.py:737: FutureWarning: Conversion of the second argument of issubdtype from `int` to `np.signedinteger` is deprecated. In future, it will be treated as `np.int32 == np.dtype(int).type`.\n",
      "  if np.issubdtype(vec.dtype, np.int):\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "[('gaseous', 0.4597316086292267),\n",
       " ('researches', 0.4340711534023285),\n",
       " ('harmful', 0.4325682818889618),\n",
       " ('physics', 0.4134013056755066),\n",
       " ('system', 0.41045206785202026),\n",
       " ('news', 0.39892005920410156),\n",
       " ('compressed', 0.3597968816757202),\n",
       " ('nautical', 0.35958218574523926),\n",
       " ('substitute', 0.3580801486968994),\n",
       " ('toledo', 0.3563697040081024)]"
      ]
     },
     "execution_count": 20,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "w2v.most_similar(positive=['solar'])"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 21,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[('advocated', 0.4853593111038208),\n",
       " ('solar', 0.4104520082473755),\n",
       " ('main', 0.40048810839653015),\n",
       " ('relationship', 0.3770222067832947),\n",
       " ('answered', 0.3546488583087921),\n",
       " ('golden', 0.33952847123146057),\n",
       " ('clue', 0.33863192796707153),\n",
       " ('harmful', 0.33825457096099854),\n",
       " ('driving', 0.3371925354003906),\n",
       " ('predominance', 0.33416372537612915)]"
      ]
     },
     "execution_count": 21,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "w2v.most_similar(positive=['system'])"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 22,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[('wanderer', 0.5605933666229248),\n",
       " ('johannes', 0.5162597894668579),\n",
       " ('reitlinger', 0.5112121105194092),\n",
       " ('independence', 0.4941261410713196),\n",
       " ('strassburg', 0.4905438721179962),\n",
       " ('yielding', 0.4500398635864258),\n",
       " ('slavish', 0.44416677951812744),\n",
       " ('contemplated', 0.44190627336502075),\n",
       " ('abolish', 0.4218079745769501),\n",
       " ('johann', 0.4171288013458252)]"
      ]
     },
     "execution_count": 22,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "w2v.most_similar(positive=['kepler'])"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## References:\n",
    "\n",
    "https://keras.io/preprocessing/sequence/\n",
    "\n",
    "https://www.tensorflow.org/tutorials/representation/word2vec"
   ]
  }
 ],
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