Dormlq incorrect size test for Row Major

[btracey]

Please see gonum/lapack#32 for more information and a reproducer.

The size test in Dormlq for row major is incorrect. Line 56 of https://github.com/xianyi/OpenBLAS/blob/develop/lapack-netlib/lapacke/src/lapacke_dormlq_work.c tests that the stride of A is less than m. However, the size of m is dependent on the Side on which A is multiplied. If A is on the left, the stride must be at least m, but if A is on the right, it only has to have stride n. Thus, the check should be conditional on the Side of the matrix multiplication.

[xianyi]

Thank you for the report.

Could you also report this bug to LAPACK developers? http://icl.cs.utk.edu/lapack-forum/viewforum.php?f=13

[btracey]

Oh, is that where we report bugs? I tried to send an email to the netlib peolpe which bounced. Thanks.

[btracey]

Bug submitted, but it needs to wait for moderation.

[btracey]

Lapack bug #133
http://www.netlib.org/lapack/Errata/index2.html#_strong_span_class_maroon_bug_133_span_strong_dormlq_c_interface_error_check

Forum post:
http://icl.cs.utk.edu/lapack-forum/viewtopic.php?f=13&t=4771

[xianyi]

@btracey , Thank you for the update.

[xianyi]

@btracey , did I merge the patch to fix this issue?

[btracey]

I downloaded the latest OpenBLAS, but our tests still fail for Dormlq. I'll look into it when I have the chance.

[btracey]

No. It did not fix the problem. The size comparison is still wrong in OpenBLAS. OpenBLAS has https://github.com/xianyi/OpenBLAS/blob/develop/lapack-netlib/lapacke/src/lapacke_dormlq_work.c

else if( matrix_order == LAPACK_ROW_MAJOR ) {
        lda_t = MAX(1,k);
        ldc_t = MAX(1,m);
        /* Check leading dimension(s) */
        if( lda < m ) {
            info = -8;
            LAPACKE_xerbla( "LAPACKE_dormlq_work", info );
            return info;
        }

While Lapack has

     r = LAPACKE_lsame( side, 'l' ) ? m : n;
        lda_t = MAX(1,k);
        ldc_t = MAX(1,m);
        /* Check leading dimension(s) */
        if( lda < r ) {
            info = -8;
            LAPACKE_xerbla( "LAPACKE_dormlq_work", info );
            return info;
        }

OpenBLAS is missing this computation of r.