Inaccurate floating point numbers used in credit offers

[abitmore]

Describe the bug

Certain credit offers cannot be accepted due to the use of inaccurate floating point numbers to calculate collateral amounts.

To Reproduce
Steps to reproduce the behavior:

1. Go to https://develop.bitshares.org/#/lending/p2p , page 2
2. Click on '$' icon of the 1.21.79 offer
3. Input amount 100 (XBTSX.HIVE), see the collateral amount is 5,999.99881 BTS, which is insufficient because the required collateral ratio is 1 HIVE / 60 BTS
4. Submit, see error

Expected behavior
No error

Screenshots

Desktop (please complete the following information):

• OS: Ubuntu 18.04
• Browser: Firefox
• Version: Latest

Additional context

[xiangxn]

I have dealt with this issue, if you have time you can review and merge.
@sschiessl-bcp @abitmore

[sschiessl-bcp]

Please check again

[abitmore]

[abitmore]

I think it's not fixed.

[xiangxn]

I replaced the division with multiplication, the precision should no longer affect
@abitmore

[sschiessl-bcp]

@xiangxn please check the calculation and if accurate now we can close

[abitmore]

Offer 1.21.67, this is fine:

but too much collateral here:

BTW for the offer 1.21.69, the percentage is strange:

[xiangxn]

Sorry, I forgot to clean up the original ceil function

[xiangxn]

I've fixed this and tested it. you can merge.

@sschiessl-bcp @abitmore

[abitmore]

I think ceil is still needed somewhere.

For example, for offer 1.21.3, if to borrow 1 BTS, the collateral 0.2381 CNY is sufficient,

But if to borrow 0.1 BTS, the collateral 0.0238 CNY is insufficient:

By the way, the amount of fee (0.86869 BTS) is wrong. It should be 1 BTS.

[xiangxn]

I have reprocessed. @abitmore

The Fee issue, I checked it, this is because the partial op number returned by the api did not cause the front-end read to fail, which requires opening a new issue #3505.

For example: /* 40 */ blind_transfer_operation This is not in the parameter list.

Because of this problem, UI's fee calculation after OP number 40 is all wrong.

[sschiessl-bcp]

Checked the cases above, looks good.

I guess the one below is not an issue, still there is a rounding error with big numbers. Funny enough, adding another 0 rounds properly again