This happens when the module files were created with one Fortran compiler, say ifort`, but it is attempting to read them with a different Fortran compiler, say gfortran. (You can never mix to different Fortran compilers in the same executable/library/module system.
You need to use a different PETSC_ARCH and configure PETSc with --with-fc=gfortran to use the gfortran compiler Barry > On Sep 6, 2022, at 11:59 AM, Han Tran <tranduc...@gmail.com> wrote: > > I used to compile my Fortran 90 code using intel compilers (i.e. intel and > impi). However, when I tried to compile using gcc, it gave the following > error. > > use petscksp > 1 > Fatal Error: File 'petscksp.mod' opened at (1) is not a GNU Fortran module > file > > It would be appreciated if you could give any hints on this issue. Thank you > so much! > > -Han
