[petsc-users] Optimized Option

[zhenglun.wei at gmail.com]

Thanks Matt,
I think I got it. Does that mean I need to configure a PETSC_ARCH as  
--with-debugging=0 so that I can used it later on.

best,
Alan

On , Matthew Knepley <knepley at gmail.com> wrote:
> 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



> 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


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20110603/50a459c7/attachment.htm>