Implementation of ParaHT, a two-stage, parallel Hessenberg-triangular reduction algorithm
This implementation was used in the paper: Thijs Steel, Raf Vandebril; Parallel two-stage reduction to Hessenberg-triangular form
To run the code, make and edit a make.inc file (an example is provided). The just run make to build the test executable.
Example output is:
# Run the parallel algorithm on a 1000x1000 randomly generated matrix
./bin/profilereduction 1000 1 16 8 8 0
n: 1000 ;runtime: 1.208396 ;error: 3.970167E-15 3.780137E-15 ;phase 1 time: 0.494774 ;phase 2 time: 0.713622 ;r: 16 ;p: 8 ;nq: 8
# Use LAPACK to reduce the same matrix
./bin/profilereduction 1000 2
n: 1000 ;runtime: 3.635724 ;error: 3.663934E-15 3.169368E-15
This shows that the algorithm is approximately three times as fast as LAPACK for this test pencil.