[petsc-users] Issue when calling multiple processors from PETSc

Ajit Desai ajit.ndesai at gmail.com
Thu Dec 24 10:16:40 CST 2015


Hello everyone,

New user of PETSc and trying to get familiar with it for parallel computing
applications.
I wrote simple hello world code using PETSc environment and found a issue
with the output. For instance :

When I compile and execute "PETSc_helloWorld.F90" code with multiple
processor. It prints following output.

MacUser$ *mpiexec -np 4 ./PETSc_helloWorld*

* Hello from PETSc World, rank: 0   of total   1  processes.*

* Hello from PETSc World, rank: 0   of total   1  processes.*

* Hello from PETSc World, rank: 0   of total   1  processes.*

* Hello from PETSc World, rank: 0   of total   1  processes.*


Similar code with MPI prints following output:

​MacUser​
$
*mpiexec -np 4 ./a.out *

* Hello from MPI World, rank: 0 *
*​  ​*
* of total  4  processes.*

* Hello from MPI World, rank: 1 *
*​  ​*
* of total ​  ​4  processes.*

* Hello from MPI World, rank: 2 *
*​  ​*
* of total  4  processes.*

* Hello from MPI World, rank: 3   of total  4  processes. *

​I am not sure is this the issue with the PETSc installation ​in my machine
or am I missing something here?
I have attached both codes and *log_summary* of PETSc for your convenience.

Thanks & Regards,

*Ajit Desai*
*--*
*  Carleton University *
*  Ottawa, Canada*
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***             WIDEN YOUR WINDOW TO 120 CHARACTERS.  Use 'enscript -r -fCourier9' to print this document            ***
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---------------------------------------------- PETSc Performance Summary: ----------------------------------------------

./PETSc_helloWorld on a arch-darwin-c-opt named Ajits-MacBook-Pro.local with 1 processor, by ajit Thu Dec 24 11:13:35 2015
Using Petsc Release Version 3.6.3, Dec, 03, 2015 

                         Max       Max/Min        Avg      Total 
Time (sec):           1.687e-04      1.00000   1.687e-04
Objects:              1.000e+00      1.00000   1.000e+00
Flops:                0.000e+00      0.00000   0.000e+00  0.000e+00
Flops/sec:            0.000e+00      0.00000   0.000e+00  0.000e+00
MPI Messages:         0.000e+00      0.00000   0.000e+00  0.000e+00
MPI Message Lengths:  0.000e+00      0.00000   0.000e+00  0.000e+00
MPI Reductions:       0.000e+00      0.00000

Flop counting convention: 1 flop = 1 real number operation of type (multiply/divide/add/subtract)
                            e.g., VecAXPY() for real vectors of length N --> 2N flops
                            and VecAXPY() for complex vectors of length N --> 8N flops

Summary of Stages:   ----- Time ------  ----- Flops -----  --- Messages ---  -- Message Lengths --  -- Reductions --
                        Avg     %Total     Avg     %Total   counts   %Total     Avg         %Total   counts   %Total 
 0:      Main Stage: 1.5859e-04  94.0%  0.0000e+00   0.0%  0.000e+00   0.0%  0.000e+00        0.0%  0.000e+00   0.0% 

------------------------------------------------------------------------------------------------------------------------
See the 'Profiling' chapter of the users' manual for details on interpreting output.
Phase summary info:
   Count: number of times phase was executed
   Time and Flops: Max - maximum over all processors
                   Ratio - ratio of maximum to minimum over all processors
   Mess: number of messages sent
   Avg. len: average message length (bytes)
   Reduct: number of global reductions
   Global: entire computation
   Stage: stages of a computation. Set stages with PetscLogStagePush() and PetscLogStagePop().
      %T - percent time in this phase         %F - percent flops in this phase
      %M - percent messages in this phase     %L - percent message lengths in this phase
      %R - percent reductions in this phase
   Total Mflop/s: 10e-6 * (sum of flops over all processors)/(max time over all processors)
------------------------------------------------------------------------------------------------------------------------
Event                Count      Time (sec)     Flops                             --- Global ---  --- Stage ---   Total
                   Max Ratio  Max     Ratio   Max  Ratio  Mess   Avg len Reduct  %T %F %M %L %R  %T %F %M %L %R Mflop/s
------------------------------------------------------------------------------------------------------------------------

--- Event Stage 0: Main Stage

------------------------------------------------------------------------------------------------------------------------

Memory usage is given in bytes:

Object Type          Creations   Destructions     Memory  Descendants' Mem.
Reports information only for process 0.

--- Event Stage 0: Main Stage

              Viewer     1              0            0     0
========================================================================================================================
Average time to get PetscTime(): 3.11e-08
#PETSc Option Table entries:
-log_summary
#End of PETSc Option Table entries
Compiled without FORTRAN kernels
Compiled with full precision matrices (default)
sizeof(short) 2 sizeof(int) 4 sizeof(long) 8 sizeof(void*) 8 sizeof(PetscScalar) 8 sizeof(PetscInt) 4
Configure options: --with-cc=gcc --with-cxx=g++ --with-fc=gfortran --download-fblaslapack --download-mpich --with-debugging=no
-----------------------------------------
Libraries compiled on Mon Dec 14 13:03:33 2015 on Ajits-MacBook-Pro.local 
Machine characteristics: Darwin-15.2.0-x86_64-i386-64bit
Using PETSc directory: /Users/ajit/Downloads/SOFTWAREs/petsc-3.6.3
Using PETSc arch: arch-darwin-c-opt
-----------------------------------------

Using C compiler: /Users/ajit/Downloads/SOFTWAREs/petsc-3.6.3/arch-darwin-c-opt/bin/mpicc  -fPIC -Wall -Wwrite-strings -Wno-strict-aliasing -Wno-unknown-pragmas -O  ${COPTFLAGS} ${CFLAGS}
Using Fortran compiler: /Users/ajit/Downloads/SOFTWAREs/petsc-3.6.3/arch-darwin-c-opt/bin/mpif90  -fPIC  -Wall -Wno-unused-variable -ffree-line-length-0 -Wno-unused-dummy-argument -O  ${FOPTFLAGS} ${FFLAGS} 
-----------------------------------------

Using include paths: -I/Users/ajit/Downloads/SOFTWAREs/petsc-3.6.3/arch-darwin-c-opt/include -I/Users/ajit/Downloads/SOFTWAREs/petsc-3.6.3/include -I/Users/ajit/Downloads/SOFTWAREs/petsc-3.6.3/include -I/Users/ajit/Downloads/SOFTWAREs/petsc-3.6.3/arch-darwin-c-opt/include -I/opt/X11/include -I/opt/local/include
-----------------------------------------

Using C linker: /Users/ajit/Downloads/SOFTWAREs/petsc-3.6.3/arch-darwin-c-opt/bin/mpicc
Using Fortran linker: /Users/ajit/Downloads/SOFTWAREs/petsc-3.6.3/arch-darwin-c-opt/bin/mpif90
Using libraries: -Wl,-rpath,/Users/ajit/Downloads/SOFTWAREs/petsc-3.6.3/arch-darwin-c-opt/lib -L/Users/ajit/Downloads/SOFTWAREs/petsc-3.6.3/arch-darwin-c-opt/lib -lpetsc -Wl,-rpath,/Users/ajit/Downloads/SOFTWAREs/petsc-3.6.3/arch-darwin-c-opt/lib -L/Users/ajit/Downloads/SOFTWAREs/petsc-3.6.3/arch-darwin-c-opt/lib -lflapack -lfblas -Wl,-rpath,/opt/X11/lib -L/opt/X11/lib -lX11 -Wl,-rpath,/opt/local/lib -L/opt/local/lib -lhwloc -Wl,-rpath,/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/7.0.2/lib/darwin -L/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/7.0.2/lib/darwin -lmpifort -lgfortran -Wl,-rpath,/usr/local/gfortran/lib/gcc/x86_64-apple-darwin14/4.9.2 -L/usr/local/gfortran/lib/gcc/x86_64-apple-darwin14/4.9.2 -Wl,-rpath,/usr/local/gfortran/lib -L/usr/local/gfortran/lib -lgfortran -lgcc_ext.10.5 -lquadmath -lm -lclang_rt.osx -lmpicxx -lc++ -Wl,-rpath,/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/clang/7.0.2/lib/darwin -L/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/clang/7.0.2/lib/darwin -lclang_rt.osx -Wl,-rpath,/Users/ajit/Downloads/SOFTWAREs/petsc-3.6.3/arch-darwin-c-opt/lib -L/Users/ajit/Downloads/SOFTWAREs/petsc-3.6.3/arch-darwin-c-opt/lib -ldl -lmpi -lpmpi -lSystem -Wl,-rpath,/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/clang/7.0.2/lib/darwin -L/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/clang/7.0.2/lib/darwin -lclang_rt.osx -ldl 
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