avoid repeated random sequences on different processes

we don't use random numbers a lot and there are no reported problems
yet.
Still, this is safer.

src/math.f90

@@ -10,8 +10,17 @@ module math
   use IO
   use config
   use YAML_types
+  use parallelization
   use LAPACK_interface
 
+#ifdef PETSC
+#include <petsc/finclude/petscsys.h>
+  use PETScSys
+#if (PETSC_VERSION_MAJOR==3 && PETSC_VERSION_MINOR>14) && !defined(PETSC_HAVE_MPI_F90MODULE_VISIBILITY)
+  use MPI_f08
+#endif
+#endif
+
   implicit none(type,external)
   public
 #if __INTEL_COMPILER >= 1900
@@ -105,7 +114,7 @@ subroutine math_init()
     call random_seed(get = seed)
   end if
 
-  call random_seed(put = seed)
+  call random_seed(put = seed + worldrank*42_MPI_INTEGER_KIND)
   call random_number(randTest)
 
   print'(/,a,i2)',              ' size  of random seed:     ', randSize

src/parallelization.f90

@@ -27,15 +27,13 @@ module parallelization
 
 #ifndef PETSC
   integer, parameter, public :: &
-    MPI_INTEGER_KIND = pI64
+    MPI_INTEGER_KIND = pI64                                                                         !< needed for MSC.Marc
   integer(MPI_INTEGER_KIND), parameter, public :: &
-    worldrank = 0_MPI_INTEGER_KIND, &                                                               !< MPI dummy worldrank
-    worldsize = 1_MPI_INTEGER_KIND                                                                  !< MPI dummy worldsize
 #else
   integer(MPI_INTEGER_KIND), protected, public :: &
+#endif
     worldrank = 0_MPI_INTEGER_KIND, &                                                               !< MPI worldrank (/=0 for MPI simulations only)
     worldsize = 1_MPI_INTEGER_KIND                                                                  !< MPI worldsize (/=1 for MPI simulations only)
-#endif
 
 #ifndef PETSC
 public :: parallelization_bcast_str