Hello I'm wondering if it is possible to put an external procedure reference in a ctx() in fortran.
I'm in the process of writing a Newton--Krylov solver for an aero-structural system. My two different codes are wrapped with python and so each code is called through python for residual and preconditioning operations. Nominally this would be a good use of petsc4py but it doesn't allow for PCShell so it is no use to me. I then wrote up the solver in Fortran and attempted to use callbacks to python for computing the required information. Using f2py, I can pass my two call back functions cb1 and cb2 fortran. A schematic of the code is below: subroutine solver(cb1, cb2) ! cb1 and cb2 are python callbacks set using f2py external cb1,cb2 petscFortranAddress ctx(2) ! I would like to do the following, but this doesn't compile ! ctx(1) = cb1 ! ctx(2) = cb2 call SNESCreate(comm,snes,ierr) call SNESSetFunction(snes,resVec,FormFunction,ctx,ierr) call KSPGetPC(ksp,pc,ierr) call PCSetType(pc,PCSHELL,ierr) call PCShellSetContext(pc,ctx,ierr) call PCShellSetApply(pc,applyaspc_fortran,ierr) end subroutine solver subroutine applyaspc_fortran(pc,inputVec,outputVec,ierr) PC pc Vec inputVec,outputVec PetscFortranAddress ctx(2) external func call PCShellGetContext(pc,ctx,ierr) func = ctx(2) call VecGetArrayF90(inputVec,states_in,ierr) call VecGetArrayF90(outputVec,states_out,ierr) ! Call the callback to python call func(states_in,states_out,shape(states_in)) call VecRestoreArrayF90(inputVec,states_in,ierr) call VecRestoreArrayF90(outputVec,states_out,ierr) end subroutine applyaspc_fortran In general, in Fortran, is it possible to put an external function reference in a module such that I wouldn't have to try to pass it through the application ctx? I realize this may be impossible to do in Fortran. Would such a procedure be possible in C? I'm only using Fortran since I'm much more familiar with it then with C. Sorry there isn't much to go on, but any suggestions would be greatly appreciated. Gaetan -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20110205/2b8cd8c4/attachment.htm>
