[petsc-dev] de-global variablelizing PETSc

[Barry Smith]

   As Jed has already noted I have an extremely ugly branch barry/make-petscoptionsobject-nonglobal which was a minimal effort change to get the PetscOptions… code to not use any global variables. I made PetscOptionsObject be inside the PetscOptionsBegin() macro but tried to hide it from the API and secretly pass it to the PetscOptionsInt() etc function. But it cannot be completely secret since it has to be passed to things like (*obj->setfromoptions)() 

 I had to make it even uglier by having PetscInitialize() call 

+
+  ierr = PetscThreadCommInitializePackage();CHKERRQ(ierr);
+  ierr = PetscThreadCommWorldInitialize();CHKERRQ(ierr);
+  ierr = AOInitializePackage();CHKERRQ(ierr);
+  ierr = PetscSFInitializePackage();CHKERRQ(ierr);
+  ierr = CharacteristicInitializePackage();CHKERRQ(ierr);
+  ierr = ISInitializePackage();CHKERRQ(ierr);
+  ierr = VecInitializePackage();CHKERRQ(ierr);
+  ierr = MatInitializePackage();CHKERRQ(ierr);
+  ierr = DMInitializePackage();CHKERRQ(ierr);
+  ierr = PCInitializePackage();CHKERRQ(ierr);
+  ierr = KSPInitializePackage();CHKERRQ(ierr);
+  ierr = SNESInitializePackage();CHKERRQ(ierr);
+  ierr = TSInitializePackage();CHKERRQ(ierr);
+  {
+    MPI_Comm comm;
+    ierr = PetscCommDuplicate(PETSC_COMM_SELF,&comm,NULL);CHKERRQ(ierr);
+    ierr = PetscCommDuplicate(PETSC_COMM_WORLD,&comm,NULL);CHKERRQ(ierr);
+  }

  since they all set global variables and thus having multiple threads around would cause grief.

   I have two questions

   1) Currently PetscOptionsObject is sometimes hidden and sometimes visible. I propose making it completely visible, the code would declare the variable before calling PetscOptionsBegin() then actually pass it into the various PetscOptionsInt() etc as opposed to secretly passing it in.  Sound OK?

   2) We need a way for initializing all the packages in PetscInitialize() instead of as needed. In master I see

#if !defined(PETSC_HAVE_DYNAMIC_LIBRARIES)
  /*
      This just initializes the most basic PETSc stuff.

    The classes, from PetscDraw to PetscTS, are initialized the first
    time an XXCreate() is called.
  */
  ierr = PetscSysInitializePackage();CHKERRQ(ierr);
#else
  preload = PETSC_FALSE;
  ierr = PetscOptionsGetBool(NULL,"-dynamic_library_preload",&preload,NULL);CHKERRQ(ierr);
  if (preload) {
    PetscBool found;
#if defined(PETSC_USE_SINGLE_LIBRARY)

   Is this suppose to be here? Or is there some branch that does it differently that is not yet in master? We could change the -dynamic_library_preload flag to something more general like -initialize_all_on_start (need better name) that forces all the initializations for both dynamic and not. This will mess up the multiple PETSc library case, how will we deal with that? So, how should we force initialization of everything at start up?

   Thanks

   Barry