[Bug-glpk] assertion failure in lpx_warm_up

[Bernard Helmstetter]

Hi,

When calling lpx_warm_up(lp), I got the following message:

Assertion failed: ret != ret; file glplpx7.c; line 557

In this file, we have:

       ret = lpx_invert(lp);
       switch (ret)
        {  case 0:
              ret = LPX_E_OK;
              break;
           case 1:
           case 2:
              ret = LPX_E_SING;
              goto done;
           default:
              insist(ret != ret);
        }

In my case, ret was equal to 3. Considering the comments above the function:

-- The routine lpx_warm_up returns one of the following exit codes:
--
-- LPX_E_OK       the LP basis has been successfully "warmed up".
--
-- LPX_E_EMPTY    the problem has no rows and/or columns.
--
-- LPX_E_BADB     the LP basis is invalid, because the number of basic
--                variables is not the same as the number of rows.
--
-- LPX_E_SING     the basis matrix is singular or ill-conditioned. */

and considering the contents of the function lpx_invert, I think that, 
in my case, the function lpx_warm_up should have returned with value 
LPX_E_BADB, instead of terminating abruptly.

Regards,

Bernard Helmstetter