AMBER Archive (2001)Subject: Re: Wrong compilation artifacts on ES40s?
From: Bill Ross (ross_at_cgl.ucsf.edu)
Date: Sun Jun 24 2001 - 14:58:33 CDT
But somehow I am still suspicious because by default I guess
Compaq gives 64bit architecture and it should be more accurate.
Here it was only 100 steps. And for these 100 steps, IBM SP3
(2-16 processors), Octanes (SGI), Alpha-Compaq work stations
(stand alone), and Linux (1-12 processors) have given same
numbers upto the last digit. I agree that I may be wrong. I
shall do long time scale simulation soon and shall verify.
You may be right - I was reacting from earlier experience
porting Amber in single-precision. Which gives me a thought:
if the ES-40 is somehow running single precision, those subtle
deviations in all the numbers would be exactly what one would
expect. You should be seeing "-DDPREC" in the compilation
statements; if not, check src/sander/Makefile, where double
precision is enforced by "PREC=DPREC".
Bill Ross
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