[ccp4bb]: Compilers and XP1000 vs Pentium

["Peter Brick" <p.brick@ic.ac.uk>]

***  For details on how to be removed from this list visit the  ***
***          CCP4 home page http://www.ccp4.ac.uk         ***

Hi,

I've compared the cpu times for identical jobs run on a Compaq AlphaStation
XP1000 Model 6/667 and on a Pentium 4 running at 2.2GHz.  On the Pentium
machine I used two different compilers - the g77 compiler and the Intel ifc
compiler.

The timings were obtained using the program CNS.  Test1 is 25 cycles of
minimization (using the minimize.inp script).  Test2 (refine.inp) combines
simulated annealing, minimization, Bfactor refinement and map calculation.
I didn't notice any significant differences in the output files. Times are
in secs.

Processor                   Test1  Test2

Compaq Alphastation 667     144    769
P4 2.2GHz g77 compiler      108    794
P4 2.2GHz ifc compiler       39    330


The Specmarks (CPF2000 base) for Alphastation is 452 while that for the
2.2GHz P4 is 779.

As has been reported by Kay Diederichs and others, the Intel ifc compiler
makes a very significant difference to the execution times.

Is it possible to compile the CCP4 suite using ifc? Which compiler switches
are needed? Unfortunately the g77 and ifc compilers are not compatible as
they use different run time libraries.


Peter

--
Peter Brick,
Blackett Laboratory, Department of Biological Sciences,
Imperial College, Prince Consort Road, London SW7 2BW, UK
Tel: 020-7594-7704  Fax: 020-7589-0191