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

[Sébastien Villemot]

Sylvestre Ledru <sylvestre at debian.org> writes:

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

Christophe is expecting 2 & 4 (Y=[1,2] and beta=2 in his example)

-- 
 .''`.    Sébastien Villemot
: :' :    Debian Developer
`. `'     http://www.dynare.org/sebastien
  `-      GPG Key: 4096R/381A7594
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