Bug#694625: libblas3gf: DGEMV does not handle properly N=0

[Sylvestre Ledru]

severity 694625 normal
thanks

Bonjour Christophe!

On 28/11/2012 15:05, Christophe TROESTLER wrote:

> Dear Maintainer,
> 
> The routine DGEMV (with TRANS = 'N') is supposed to perform the
> operation
> 
>     y ← beta * y + alpha * A * x
> 
> where the matrix A has dimensions M×N.  In particular, if N=0 (and M >
> 0), A * x is the null vector (all elements are given by sums on an
> empty set of indices).  Consequently, if N = 0, the operation should
> be
> 
>     y ← beta * y
> 
> and NOT leave y untouched.  For your convenience, I have attached a
> program demonstrating the latter (wrong) behavior.

I am getting:
   1.0000000000000000
   2.0000000000000000
What should I get ?
2 & 2 ?

Thanks
Sylvestre