[petsc-users] Optimized Option

[Matthew Knepley]

On Fri, Jun 3, 2011 at 3:38 PM, Barry Smith <bsmith at mcs.anl.gov> wrote:

>
> On Jun 3, 2011, at 3:30 PM, Matthew Knepley wrote:
>
> > 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
>
>    You should provide a value for the environmental variable PETSC_ARCH
> before running ./configure
>
>   For example   PETSC_ARCH=arch-debug    ./configure --with-debugging=1
> otherstuff
>   then PETSC_ARCH=arch-opt    ./configure --with-debugging=0   otherstuff


This is fragile since it depends on your shell. Just use

  ./configure --with-debugging=0 --PETSC_ARCH=arch-opt <otherstuff>

   Matt


> >
> >     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
>
>


-- 
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
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