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[Lapack] bug in gemv routines

Dear BLAS developers,

there seems to be a bug in the gemv routines for the special
case where n=0 and beta /not= 1, i.e.,

call dgemv(TRANS,M,    0,    ALPHA, A, LDA, X, INCX,     0.5,     Y, INCY)

leaves Y unchanged but according to the manpage n=0 is allowed
and this operation should scale Y.

This bug is present in all BLAS implementations I have tested, including
NETLIB-reference, AMD-ACML, Intel-MKL, GOTO, GOTO2, ATLAS,
SUN-performance-lib.

The gbmv-routines seem also to be affected by this bug.
Level 3 routines (at least gemm-routines) handle this situation
correctly.

Best regards,
Dennis Diehl


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