Aleksandar Donev wrote: > See > http://www-unix.mcs.anl.gov/petsc/petsc-as/snapshots/petsc-current/docs/manualpages/Vec/VecDuplicateVecsF90.html This one is simpler to understand: http://www-unix.mcs.anl.gov/petsc/petsc-as/snapshots/petsc-current/docs/manualpages/Vec/VecGetArrayF90.html Aleks