From chemistry-request@ccl.net Wed Dec 8 13:51:29 2004 Received: from mb1i1.ns.pitt.edu (mb1i1.ns.pitt.edu [136.142.11.139]) by server.ccl.net (8.12.8/8.12.8) with ESMTP id iB8IpSdA004174 for ; Wed, 8 Dec 2004 13:51:28 -0500 Received: from [127.0.0.1] ([136.142.109.16]) by pitt.edu (PMDF V6.2-X27 #30902) with ESMTP id <01LI5PV5DGTY000MTL~at~mb1i1.ns.pitt.edu> for CHEMISTRY~at~ccl.net; Wed, 08 Dec 2004 14:06:24 -0500 (EST) Date: Wed, 08 Dec 2004 14:06:21 -0500 From: Kadir Diri Subject: Re: CCL:Computation Resource Requirement. In-reply-to: <41B5CEE1.10203~at~ndsu.nodak.edu> To: Pijush Ghosh Cc: CHEMISTRY~at~ccl.net Message-id: <41B750AD.5080103~at~visual1.chem.pitt.edu> MIME-version: 1.0 Content-type: text/plain; format=flowed; charset=ISO-8859-1 Content-transfer-encoding: 7bit X-Accept-Language: en-us, en, tr User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.2) Gecko/20040803 References: <41B5CEE1.10203~at~ndsu.nodak.edu> X-Spam-Status: No, hits=3.0 required=7.5 tests=NO_RDNS2 autolearn=no version=2.61 X-Spam-Checker-Version: SpamAssassin 2.61 (1.212.2.1-2003-12-09-exp) on servernd.ccl.net Hi! What you can do to get an idea about the timings on a single cpu is the following: do a smaller calculation (smaller basis set and/or smaller molecule). Then scale the timings accordingly for larger basis sets and more atoms. In Hartree-Fock, the 2 electron integrals will scale as N^4 but the integral transformation will scale as N^5. As to the case with multiple CPU`s, it depends on many factors, for example on how good the code that you use is. Also, the speed will vary > from one architecture to another. It is also important how the code works, i.e. whether it uses shared memory on a multiple cpu machine or whether it runs across many nodes. There are probably many other factors, like the speed and the configuration of the network, so it is not very easy to answer that part of your question, but you will be able to figure out the answer after a few test calculations. kadir Pijush Ghosh wrote: > CCL Users, > being new to the field of computational quantum mechanics, i > have a basic question on the requirement of the resources for this > type of computation. Can anybody cite any reference where i can get > some relation between number of processors and time required with > that of number of atoms in a system , basis set used, etc. > In my system of Hydroxyapatite- polymer I have the following details: > > atom number > > Calcium 20 > Phosphorous 12 > Oxygen 54 > Hydrogen 10 > Carbon 3 > > > Basis set - 6-31+G** > Method - HF (Hartree Fock) > > > can somebody give idea on processor-hour required. All my > simulations are run on NCSA machines. > > > All suggesions and information appreciated in advance. > > > Pijush Ghosh. > NDSU. > > > > -= This is automatically added to each message by the mailing script =- > To send e-mail to subscribers of CCL put the string CCL: on your > Subject: line > and send your message to: CHEMISTRY~at~ccl.net > > Send your subscription/unsubscription requests to: > CHEMISTRY-REQUEST~at~ccl.net HOME Page: http://www.ccl.net | Jobs Page: > http://www.ccl.net/jobs > If your mail is bouncing from CCL.NET domain send it to the maintainer: > Jan Labanowski, jlabanow~at~nd.edu (read about it on CCL Home Page) > -+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ > > > >