[Pw_forum] My installation of Espresso 4.1/4.2 is not passing benchmarks

[Lorenzo Paulatto]

On Tue, 01 Jun 2010 02:05:35 +0200, Christopher O'Brien  
<cjobrien at ncsu.edu> wrote:
> Perhaps the most disturbing were those involving simple SCF calculations  
> such as:
>> Checking atom-pbe...discrepancy in pressure detected
>> Reference: -14.44, You got: -14.43
>> Checking atom-sigmapbe...discrepancy in pressure detected
>> Reference: -15.02, You got: -15.03

Dear Christopher,
I wouldn't worry about such a discrepancy. Those test involve isolated  
atoms, where pressure is not really meaningful. In general, different  
optimized algebraic libraries (ATLAS, MKL, ACML...) use different tricks  
to increase performance but, as a trade-off, they are not alway  
consistent. This introduces some noise in the parts of the code that are  
more sensible to it, especially pressure.

regards

-- 
Lorenzo Paulatto

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