[CP2K:582] Re: cp2k chooses unsupported FFT grids

[Juerg Hutter]

Hi Axel

do I get it right:
CP2K would like to use 100, but because of the FFT length
table (see fftessl_lib.F) is forced to use 110. However,
your ESSL library complains that 110 is not a valid transform length.

The table in fftessl_lib.F was copied from the ESSL manual.

see
http://publib.boulder.ibm.com/infocenter/clresctr/vxrx/index.jsp?topic=/com.ibm.cluster.essl.doc/essl_linux422/am501403194.html

where it says
Acceptable Lengths for the Transforms
Use the following formula to determine acceptable transform lengths:
n = (2h) (3i) (5j) (7k) (11m)    for n <= 37748736

where:
h = 1, 2, ..., 25
  i = 0, 1, 2
  j, k, m = 0, 1

so 110 is a valid length.
Do you have some very special version of ESSL?

greetings

Juerg

----------------------------------------------------------
Juerg Hutter                   Phone : ++41 44 635 4491
Physical Chemistry Institute   FAX   : ++41 44 635 6838
University of Zurich           E-mail: hut... at pci.uzh.ch
Winterthurerstrasse 190
CH-8057 Zurich, Switzerland
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On Tue, 15 Jan 2008, Axel wrote:

>
> hi again,
>
> small correction, after sprinkling a few debug prints into the code i
> found,
> that the code picks a dimension of 100 and then suggests to use 110.
> my bad, i'm too used to fftw grids obviously. however, the main
> problem
> remains. 100 is not listed as supported by fftessl, so how come it can
> select it?
> with -O2 i'm not exactly using an aggressive optimization...
>
> puzzled,
>    axel.
>
>
> On Jan 15, 4:49 pm, Axel <akoh... at gmail.com> wrote:
>> hi!
>>
>> i'm trying to run the 32 water quickstep benchmark on an IBM machine
>> with ESSL and the job stops with an error message, that a dimension of
>> 110 is not supported. while the error makes sense (essl does not
>> support
>> roots of 11, only fftw), shouldn't the code pick a compatible number?
>> i specified FFTESSL explicitely as preferred library and it is
>> compiled in
>> (or else, there would be no error)...
>>
>> any suggestions?
>>
>> cheers,
>>     axel.
> >
>