LAPACKE_?trexc_work: ldq must be always >= n

[vladimir-ch]

In row-major case, LAPACKE_?trexc_work requires ldq >= n even when compq is not 'v', that is, when the matrix Q is not referenced. The ldq parameter is always used conditionally only if compq is 'v', so the ldq >= n check should be also done only in that case.

In ?TREXC the corresponding check is:

IF( LDQ.LT.1 .OR. ( WANTQ .AND. LDQ.LT.MAX( 1, N ) ) ) THEN
   INFO = -6

[langou]

Thanks for spotting this. What about on line 54 of LAPACKE_dtrexc_work.c:

        if(( ldq < n )&&(LAPACKE_lsame( compq, 'v' ))) {

Note: LAPACKE does not check for ( ldq < 1 ) if the array is not referenced. This is fine. This is not consistent with LAPACK. LAPACK (Fortran) does check for ( ldq < 1 ).

Do you want to submit a pull request? And if you have a better solution for changing the check, please go ahead.

Cheers,
Julien.