Inconsistent results on bluegene

[Yu-Heng Tseng]

Hi,

Here is the description of the problem.
In the test directory under test/fandc/
there is a Fortran test file called "pnf_test.F"
This file generates an array has size 256x256x256 and output it to a 
pnf_test.nc file and read it back.

In other machines or using gcc to compile the library, it compares the 
original array with the readin new array. The output have
diff, delmax, delmin

They should be all zero which represents the difference between the 
new array and old array. Unfortunitely, I got some non-zero values 
when I use 2, 8, 16 processors which means the new readin array and 
original array are not identical.
The only correct result is using 1 processor. The new readin array is 
identical to the old array.

I am not sure if there is anything wrong on the compiler or any 
problem. It looks fine when I use gcc to compile. Thank you so much 
for your help!

Yu-heng
---------------------------------------------------
Yu-Heng Tseng

Computational Research Division
Lawrence Berkeley National Laboratory
One Cyclotron Rd, MS: 50F-1650
Berkeley, CA94720
YHTseng at lbl.gov
510.495.2904

----- Original Message -----
From: Rob Ross <rross at mcs.anl.gov>
Date: Wednesday, April 12, 2006 7:28 pm
Subject: Re: Inconsistent results on bluegene

> Hi,
> 
> Can you describe how the results are inconsistent?
> 
> Thanks,
> 
> Rob
> 
> Yu-Heng Tseng wrote:
> > Hi,
> > 
> > I am doing a testing on bluegene using. Surprisely, the results 
> are not 
> > consistent when I use
> > multiple processors. There is no error when I compile and 
> install the 
> > library  I believe.
> > I use the test case from /fandc/pnf_test.F
> > 
> > The compiler I am using is "blrts_xlc" I am not sure what cause 
> the 
> > problem.
> > But when I use gcc to compile it. The results are consistent for 
> > multiple processors.
> > Please give me some advices! Thanks!
> > 
> > Yu-heng
> > 
>