As Jed mentioned - I use system blaslapack on linux/ Mac [no need for --download-fblaslapack] on these. And then I have a single install of MPICH in my PATH that I use for all my builds. You can get this with: ./configure --prefix=$HOME/soft/mpich-3.3.2 CFLAGS= COPTFLAGS= FFLAGS= FOPTFLAGS= CXXFLAGS= CXXOPTFLAGS= [and then add $HOME/soft/mpich-3.3.2/bin in PATH] I use ccache differently - not wrap MPI wrappers - but just gcc/g++ $ which gcc /usr/lib64/ccache/gcc If using in-pace install then PETSc configure does not rebuild packages unless the configure options to build that package has changed [or if its installed from git - gitcommit has changed] And its best not to change options to configure - when reusing PETSC_ARCH [however - changes within configure can change some of the default compiler flags or package options - that can result in a rebuild] Satish On Sun, 22 Mar 2020, Jacob Faibussowitsch wrote:

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Do you mean 32-bit/64-bit (pointers) or --with-64-bit-indices=0/1 ? [or do you have --known-64-bit-blas-indices in the mix?] Sorry, I mean configuring petsc with —with-64-bit-indices=1 here.

Best regards,

Jacob Faibussowitsch (Jacob Fai - booss - oh - vitch) Cell: (312) 694-3391

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On Mar 22, 2020, at 4:24 PM, Satish Balay <[email protected]> wrote:

Do you mean 32-bit/64-bit (pointers) or --with-64-bit-indices=0/1 ? [or do you have --known-64-bit-blas-indices in the mix?]

Satish

On Sun, 22 Mar 2020, Jacob Faibussowitsch wrote:

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Hello all,

As part of development, I have several arch folders lying around in my PETSC_DIR namely a 32-bit OSX, 64-bit OSX, 32-bit linux with valgrind, 64-bit linux with valgrind, and a 32-bit up to date with current master. All of these have a —download-mpich —download-fblaslapack and hence their own copy of each (so that’s 5 copies of each, plus other duplicated packages im sure). At this stage, even getting the bare minimum of these arches ready for dev work after a rebase/git pull takes decades as package versions, or conf settings change, forcing a rebuild of the same packages multiple times.

My question(s): What petsc ./configure options are necessary to change the configuration of each library w.r.t. petsc? i.e. can my 64-bit arches use my 32-bit MPICH/fblaslapack and vice-versa? Does this change when I have —with-debug on or off? If so, what other packages have a similar ability? Is there anywhere in ./configure —help where this kind of information would be documented?

I suspect that this hasn’t been fully explored since its primarily a developer “problem” and not one the average user will run into/care about (since they usually aren’t building petsc multiple times). I’m sure everyone has their own ways of tackling this problem, I’d love to hear them.

Best regards,

Jacob Faibussowitsch (Jacob Fai - booss - oh - vitch) Cell: (312) 694-3391