[petsc-users] Optimized Option

[Matthew Knepley]

On Fri, Jun 3, 2011 at 3:28 PM, <zhenglun.wei at gmail.com> wrote:

> Thanks for your reply.
> So, if I want to use '--with-debugging=0', what is the PETSC_ARCH equal to?
>

When you run configure, at the end it prints out a LARGE message that
indicates

  - What PETSC_ARCH it has chosen

  - Exactly the command line to run when building

This information is also stored in configure.log

    Matt

I just tried to use PETSC = arch-opt, and a error message comes up:
> ~/petsc-dev/conf/variables:95: ~/petsc-dev/arch-opt/conf/petscvariables: No
> such file or directory
> ~l/petsc-dev/conf/rules:1018: ~/petsc-dev/arch-opt/conf/petscrules: No such
> file or directory
> make: *** No rule to make target `~l/petsc-dev/arch-opt/conf/petscrules'.
> Stop.
> this really confused me.
>
> thanks,
> Alan
>
> On , Barry Smith <bsmith at mcs.anl.gov> wrote:
> >
> >
> > On Jun 3, 2011, at 2:57 PM, Alan Wei wrote:
> >
> >
> >
> > > Dear Sir/Madam,
> >
> > >     Lately, I read there is a optimized version of PETSc by using
> '--with-debugging=0'. I have two questions here:
> >
> > > 1, Do I need to use '/config/configure.py ... --with-debugging=0' when
> I configure the PETSc in order to use the non-debugging version of PETSc?
> Therefore, if I want to switch PETSc between these two versions, I have to
> keep configuring.
> >
> >
> >
> >
> >
> >   ABSOLUTELY NOT.  You use two different values of the environmental
> variable PETSC_ARCH and switch back and forth by changing the variable. You
> can even change it on the make command line. For example make mycode
> PETSC_ARCH=arch-opt
> >
> >
> >
> >   Note that you can use any name you want for the values of PETSC_ARCH. I
> often use arch-debug and arch-opt to keep track of them.
> >
> >
> >
> >
> >
> > > 2, I was using the '--with-debugging=0' to configure the PETSc.
> However, I tested the computational rate by executing the ex29.c. The
> non-debugging version does not improve the speed much; in the contrary, it
> slow down the speed a little bit. The comparison is attached here. Any idea
> on this.
> >
> >
> >
> >    It depends on the compiler and particular code you are running. We
> recommend using the option -log_summary to see how much time is spent in
> each part of the computation and how much it gets better with optimization.
> >
> >
> >
> >
> >
> >   Barry
> >
> >
> >
> >
> >
> > >
> >
> > > thanks in advance,
> >
> > > Alan
> >
> > >
> >
> > >
> >
> >
> >
> >




-- 
What most experimenters take for granted before they begin their experiments
is infinitely more interesting than any results to which their experiments
lead.
-- Norbert Wiener
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20110603/5063de89/attachment-0001.htm>