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[Scalapack] NB and MB in the example 1 program


hello,

for information ulf is speaking of:
        http://www.netlib.org/scalapack/examples/example1.f

MB must equal NB for PDGESV (a rather well hidden fact)

hidden on line 88 of pdgesv.f for information

I wonder if the fourth argument in the second call to DESCINIT in 
example1.f shouldn't be MB rather than NB, since the fourth argument is 
MB in the first call to DESCINIT.

mm ok so the block size for the A matrix is MB-by-NB,
and the block size for B for the matrix B is NB-by-NBRHS,
so yes you are right might look better with an MB-by-NBRHS when you look 
at B.

Now the DESCINIT of B is also used for 'X' and you certainly want the 
block size of X to be NB-by-NBRHS, so ....

I also thinks the fact that MB must equal NB for PDGESV merits a comment 
in example1.f

yes I think this is a good idea,

other scalapackers, yes, no?

thanks Ulf for pointing this out.
Julien


On Mon, 17 Apr 2006, Ulf Andersson wrote:

Hi,

This may not be considered much of a bug since MB must equal NB for
PDGESV (a rather well hidden fact), but I wonder if the fourth argument
in the second call to DESCINIT in example1.f shouldn't be MB rather than
NB, since the fourth argument is MB in the first call to DESCINIT.

I also thinks the fact that MB must equal NB for PDGESV merits a comment
in example1.f

ulfa


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