COIN backend should support basis status and tableau data functions

[mkoeppe]

This is for COIN backend support in #18733 and #18688.

Should add (1) getBasisStatus, setBasisStatus, (2) getBInvARow, getBInvACol, getBasics, to src/sage/numerical/backends/coin_backend.{pxd,pyx}

Possible that one needs to add other functions as well, such as enableSimplexInterface...

Reference to the relevant Clp header file: ​https://projects.coin-or.org/Osi/browser/trunk/Osi/src/OsiClp/OsiClpSolverInterface.hpp?rev=1472

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​9fdbd84

Fix bugs in CoinBackend::get/set_basis_status(); Add doctests

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​3644950

Add CoinBackend::get_binva_row, get_binva_col

[vdelecroix]

Please fill the Authors field with your full name.

Instead of sage_malloc you could use check_malloc (that checks that the memory is indeed allocated and raises an error if not).

Otherwise, everything looks clean and tests run smoothly on my computer (with Coin installed).

Vincent

[yzh]

Instead of sage_malloc you could use check_malloc (that checks that the memory is indeed allocated and raises an error if not).

Thanks a lot for reviewing the ticket. Does one call sage_free to free the memory allocated by check_malloc? Since sage_malloc is used throughout the file, I was trying to be consistent. Would you suggest replacing them all by check_malloc? Or perhaps better to update them using #18868?

[vdelecroix]

Hi Yuan,

Replying to yzh:

Instead of sage_malloc you could use check_malloc (that checks that the memory is indeed allocated and raises an error if not).

Thanks a lot for reviewing the ticket. Does one call sage_free to free the memory allocated by check_malloc? Since sage_malloc is used throughout the file, I was trying to be consistent. Would you suggest replacing them all by check_malloc? Or perhaps better to update them using #18868?

I do not think that #18868 is good idea in this case. You will create a Python object for nothing.

check_malloc is equivalent to sage_malloc except that it will raise an error in case the memory was not allocated (where sage_malloc just returns NULL). So the memory should be freed with sage_free. You can safely replace occurrences of sage_malloc by check_malloc. Moreover you can always replace

my_ptr = sage_malloc(12)
if my_ptr == NULL:
    raise MemoryError("allocation failed")

by

my_ptr = check_malloc(12)

Vincent

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​3ab6b33

replace sage_malloc by check_malloc

[yzh]

Thank you, Vincent. I changed sage_malloc to check_malloc.

[vdelecroix]

The patchbot reported some errors (when cbc is not installed)

sage -t --long src/sage/numerical/backends/coin_backend.pyx
**********************************************************************
File "src/sage/numerical/backends/coin_backend.pyx", line 1260, in sage.numerical.backends.coin_backend.CoinBackend.get_basis_status
Failed example:
    p.solve()
    ...
    NameError: name 'p' is not defined
**********************************************************************
File "src/sage/numerical/backends/coin_backend.pyx", line 1285, in sage.numerical.backends.coin_backend.CoinBackend.get_basis_status
Failed example:
    lp_coin = lp.get_backend()
    ...
    NameError: name 'lp' is not defined
**********************************************************************

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​c2488a8

specify optional-cbc in doctests

[yzh]

Oops, I forgot to indicate optional - cbc at some places

[vdelecroix]

Good to go!