[petsc-users] petsc without MPI

[Balay, Satish]

Generally - even when one wants sequential build - its best use MPICH [or openMPI] when using multiple MPI based packages.

[this is to avoid conflicts - if any - in the seqential MPI stubs of these packages]

And run the code sequentially..

Satish

On Tue, 26 Nov 2019, Smith, Barry F. wrote:

> 
>   I agree this is confusing. https://gitlab.com/petsc/petsc/merge_requests/2331 the flag PETSC_HAVE_MPI will no longer be set when MPI is not used (only MPIUNI is used).
> 
>    Barry
> 
>   The code API still has MPI* in it with MPI but they are stubs that just handle the sequential code and do not require an installation of MPI.
> 
> 
> > On Nov 19, 2019, at 2:07 PM, Povolotskyi, Mykhailo via petsc-users <petsc-users at mcs.anl.gov> wrote:
> > 
> > I see.
> > 
> > Actually, my goal is to compile petsc without real MPI to use it with libmesh.
> > 
> > You are saying that PETSC_HAVE_MPI is not a sign that Petsc is built with MPI. It means you have MPIUNI which is a serial code, but has an interface of MPI.
> > 
> > Correct?
> > 
> > On 11/19/2019 3:00 PM, Matthew Knepley wrote:
> >> On Tue, Nov 19, 2019 at 2:58 PM Povolotskyi, Mykhailo <mpovolot at purdue.edu> wrote:
> >> Let me explain the problem.
> >> 
> >> This log file has 
> >> 
> >> #ifndef PETSC_HAVE_MPI
> >> #define PETSC_HAVE_MPI 1
> >> #endif
> >> 
> >> while I need to have PETSC without MPI.
> >> 
> >> If you do not provide MPI, we provide MPIUNI. Do you see it linking to an MPI implementation, or using mpi.h?
> >> 
> >>     Matt
> >>  
> >> On 11/19/2019 2:55 PM, Matthew Knepley wrote:
> >>> The log you sent has configure completely successfully. Please retry and send the log for a failed run.
> >>> 
> >>>   Thanks,
> >>> 
> >>>      Matt
> >>> 
> >>> On Tue, Nov 19, 2019 at 2:53 PM Povolotskyi, Mykhailo via petsc-users <petsc-users at mcs.anl.gov> wrote:
> >>> Why it did not work then?
> >>> 
> >>> On 11/19/2019 2:51 PM, Balay, Satish wrote:
> >>> > And I see from configure.log - you are using the correct option.
> >>> >
> >>> > Configure Options: --configModules=PETSc.Configure --optionsModule=config.compilerOptions --with-scalar-type=real --with-x=0 --with-hdf5=0 --with-single-library=1 --with-shared-libraries=0 --with-log=0 --with-mpi=0 --with-clanguage=C++ --with-cxx-dialect=C++11 --CXXFLAGS="-fopenmp -fPIC" --CFLAGS="-fopenmp -fPIC" --with-fortran=0 --FFLAGS="-fopenmp -fPIC" --with-64-bit-indices=0 --with-debugging=0 --with-cc=gcc --with-fc=gfortran --with-cxx=g++ COPTFLAGS= CXXOPTFLAGS= FOPTFLAGS= --download-metis=0 --download-superlu_dist=0 --download-parmetis=0 --with-valgrind-dir=/apps/brown/valgrind/3.13.0_gcc-4.8.5 --download-mumps=1 --with-mumps-serial=1 --with-fortran-kernels=0 --with-blaslapack-lib="-Wl,-rpath,/apps/cent7/intel/compilers_and_libraries_2017.1.132/linux/mkl/lib/intel64  -L/apps/cent7/intel/compilers_and_libraries_2017.1.132/linux/mkl/lib/intel64 -lmkl_intel_lp64 -lmkl_gnu_thread -lmkl_core " --with-blacs-lib=/apps/cent7/intel/compilers_and_libraries_2017.1.132/linux/mkl/lib/intel64/libmkl_blacs_intelmpi_lp64.so --with-blacs-include=/apps/cent7/intel/compilers_and_libraries_2017.1.132/linux/mkl/include --with-scalapack=0
> >>> > <<<<<<<
> >>> >
> >>> > And configure completed successfully. What issue are you encountering? Why do you think its activating MPI?
> >>> >
> >>> > Satish
> >>> >
> >>> >
> >>> > On Tue, 19 Nov 2019, Balay, Satish via petsc-users wrote:
> >>> >
> >>> >> On Tue, 19 Nov 2019, Povolotskyi, Mykhailo via petsc-users wrote:
> >>> >>
> >>> >>> Hello,
> >>> >>>
> >>> >>> I'm trying to build PETSC without MPI.
> >>> >>>
> >>> >>> Even if I specify --with_mpi=0, the configuration script still activates
> >>> >>> MPI.
> >>> >>>
> >>> >>> I attach the configure.log.
> >>> >>>
> >>> >>> What am I doing wrong?
> >>> >> The option is --with-mpi=0
> >>> >>
> >>> >> Satish
> >>> >>
> >>> >>
> >>> >>> Thank you,
> >>> >>>
> >>> >>> Michael.
> >>> >>>
> >>> >>>
> >>> 
> >>> 
> >>> 
> >>> -- 
> >>> 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
> >>> 
> >>> https://www.cse.buffalo.edu/~knepley/
> >> 
> >> 
> >> -- 
> >> 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
> >> 
> >> https://www.cse.buffalo.edu/~knepley/
>