Thanks, David. i appreciate your response.<br><br>o.<br><br><b><i>David van der Spoel <spoel@xray.bmc.uu.se></i></b> wrote:<blockquote class="replbq" style="border-left: 2px solid rgb(16, 16, 255); margin-left: 5px; padding-left: 5px;"> Omololu Akin-Ojo wrote:<br>> Hi,<br>> <br>> i use GROMACS & i like it because it is so fast. But, i would like to <br>> know if GROMACS "cut corners" ? Otherwise, why is it is so fast?<br>> if you have a fortran compiler on an Opteron box, GROMACS does not use <br>> the assembly loops. Right? So, why is it blazingly fast?<br>> <br>> o.<br><br>gromacs does not cut corners...<br>Most important we do not compute stuff that we know will give zero as a <br>result anyway, this gives 20-30% compared to other codes.<br>Single precision is a factor of two faster than double, assembly is a <br>factor of two faster than C/Fortran, and finally our innerloops are <br>completely unrolled, this probably also gives a factor
of 1.5.<br>So if you multiply it all you have a significant factor (even in double <br>precision).<br><br><br>> <br>> ------------------------------------------------------------------------<br>> Sponsored Link<br>> <br>> Try Netflix today! With plans starting at only $5.99 a month what are <br>> you waiting for? <br>> <http:><br>> <br>> <br>> ------------------------------------------------------------------------<br>> <br>> _______________________________________________<br>> gmx-users mailing list gmx-users@gromacs.org<br>> http://www.gromacs.org/mailman/listinfo/gmx-users<br>> Please don't post (un)subscribe requests to the list. Use the <br>> www interface or send it to gmx-users-request@gromacs.org.<br>> Can't post? Read http://www.gromacs.org/mailing_lists/users.php<br><br><br>-- <br>David.<br>________________________________________________________________________<br>David van der Spoel, PhD, Assoc. Prof.,
Molecular Biophysics group,<br>Dept. of Cell and Molecular Biology, Uppsala University.<br>Husargatan 3, Box 596, 75124 Uppsala, Sweden<br>phone: 46 18 471 4205 fax: 46 18 511 755<br>spoel@xray.bmc.uu.se spoel@gromacs.org http://folding.bmc.uu.se<br>++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++<br>_______________________________________________<br>gmx-users mailing list gmx-users@gromacs.org<br>http://www.gromacs.org/mailman/listinfo/gmx-users<br>Please don't post (un)subscribe requests to the list. Use the <br>www interface or send it to gmx-users-request@gromacs.org.<br>Can't post? Read http://www.gromacs.org/mailing_lists/users.php<br></http:></blockquote><br><p> 
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