[petsc-dev] PETSC_DIR and PETSC_ARCH: used to distinguish between multiple applications ?

[Barry Smith]

  There are two ways to build different versions of PETSc needed by other packages.

1)   Use PETSC_DIR and PETSC_ARCH to distinguish different installs. For example to build a version of PETc that uses hypre and one that doesn't you can do one install with for example PETSC_ARCH=arch-basic and another with PETSC_ARCH=arch-hypre where one adds --download-hypre to the second install.

   export PETSC_ARCH=arch-basic
   ./configure 
   make

   export PETSC_ARCH=arch-hypre
    ./configure --download-hypre
    make 


the other approach is to use

2)  the ./configure --prefix option with each build, for example 

   ./configure --prefix=/Users/me/petsc-basic 
   make
   make install 


and 

   ./configure --prefix=/Users/me/petsc-hypre --download-hypre
   make
   make install

  They are actually really similar, the only difference is that when using the first case the libraries are in 

   $PETSC_DIR/$PETSC_ARCH

    while in the second case they are in

    $prefix 

    and there is not PETSC_ARCH

    The approach with --prefix is more conventional, since it is used with gnu packages. The $PETSC_ARCH approach has less 
directory duplication since everything is in the $PETSC_DIR directory.

  Barry



> On Apr 23, 2017, at 7:08 PM, Kevin Buckley <kevin.buckley.ecs.vuw.ac.nz at gmail.com> wrote:
> 
> Been a while since I have(re)installed a PETSc, but I have just
> come into install it as a dependecy for a different package to
> that for which I have installed it in the past.
> 
> The original package has a requirement for
> 
>  --with-clanguage=cxx
> 
> whereas the current one doesn't, but it does have a requirement for
> different external packages, eg hypre.
> 
> In terms of laying out PETSc, can (should ?) one use PETSC_DIR
> and PETSC_ARCH: to combine everything PETSc-related under one,
> top-level, say
> 
> /path/to/PETSC/3.7.5
> 
> with subdirs, or do the differing requirements demand two different "top-level "
> 
> /path/to/PETSC/3.7.5/Package1
> 
> /path/to/PETSC/3.7.5/Package2
> 
> hierachies, each then with duplicated files across the two?
> 
> Any pointers welcome,
> Kevin
> 
> ---
> Kevin M. Buckley
> 
> eScience Consultant
> School of Engineering and Computer Science
> Victoria University of Wellington
> New Zealand