[Pw_forum] ATLAS DSYGVX problem + mailing list question

[Riccardo Di Meo]

Paolo Giannozzi wrote:
> On May 25, 2010, at 15:12 , Riccardo Di Meo wrote:
>
>   
>> ** On entry to DSYGVX parameter number 20 had an illegal value
>>     
>
> called by PW/rdiaghg.f90, parameter number 20 is lwork. It is set  
> according
> to what the lapack manual says it should be set to. Please print its  
> value and
> see if there is something obviously wrong
>   
well, I don't know why the value is wrong, but it's clear something 
fishy is going on: using a "print *," the plain version reports lwork to 
be 48 (N = 6, NB = 32), where the atlas one reports lwork to be 24 (N = 
6, NB = 1).

It seems therefore that the culprit is the line:

     nb = ILAENV( 1, 'DSYTRD', 'U', n, -1, -1, -1 )

which produces two different results with the same input, although I 
don't know why.
> Paolo
>
> PS: do not compile with 64-bit integers as default. It produces all  
> sort of
> funny problem
I used the default flags for compilation (which, I assume, produce 64 
bit integers, if gfortran works as gcc does), however I didn't found a 
way to downgrade the integer size to 4 (besides the obvious, and wrong 
way, of -m32), or at least the manpages for gcc and gfortran doesn't 
seem to mention the possibility.

Am I missing something?

Hope this helps, let me know if more info are needed
Thank you,
Riccardo