Re: CCL:Computation Resource Requirement.

[Pijush Ghosh <pijush.ghosh{at}ndsu.nodak.edu>]

 I thank you all for your valuable suggestions on my issue of
 coumputation resource requirement. I think they are of big help to me.
 Pijush.
 Kadir Diri wrote:
> 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.
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