1fe66ebccSMartin Diehl#include <petsc/finclude/petscdmda.h> 2*c5e229c2SMartin Diehlmodule ex13f90auxmodule 3fe66ebccSMartin Diehl use petscdm 4c4762a1bSJed Brown implicit none 5c4762a1bSJed Browncontains 6c4762a1bSJed Brown ! 7c4762a1bSJed Brown ! A subroutine which returns the boundary conditions. 8c4762a1bSJed Brown ! 9c4762a1bSJed Brown subroutine get_boundary_cond(b_x, b_y, b_z) 10c4762a1bSJed Brown DMBoundaryType, intent(inout) :: b_x, b_y, b_z 11c4762a1bSJed Brown 12c4762a1bSJed Brown ! Here you may set the BC types you want 13c4762a1bSJed Brown b_x = DM_BOUNDARY_GHOSTED 14c4762a1bSJed Brown b_y = DM_BOUNDARY_GHOSTED 15c4762a1bSJed Brown b_z = DM_BOUNDARY_GHOSTED 16c4762a1bSJed Brown 17c4762a1bSJed Brown end subroutine get_boundary_cond 18c4762a1bSJed Brown ! 19c4762a1bSJed Brown ! A function which returns the RHS of the equation we are solving 20c4762a1bSJed Brown ! 21c4762a1bSJed Brown function dfdt_vdp(t, dt, ib1, ibn, jb1, jbn, kb1, kbn, imax, jmax, kmax, n, f) 22c4762a1bSJed Brown ! 23c4762a1bSJed Brown ! Right-hand side for the van der Pol oscillator. Very simple system of two 24c4762a1bSJed Brown ! ODEs. See Iserles, eq (5.2). 25c4762a1bSJed Brown ! 26c4762a1bSJed Brown PetscReal, intent(in) :: t, dt 27c4762a1bSJed Brown PetscInt, intent(in) :: ib1, ibn, jb1, jbn, kb1, kbn, imax, jmax, kmax, n 28c4762a1bSJed Brown PetscReal, dimension(n, ib1:ibn, jb1:jbn, kb1:kbn), intent(inout) :: f 29c4762a1bSJed Brown PetscReal, dimension(n, imax, jmax, kmax) :: dfdt_vdp 30c4762a1bSJed Brown PetscReal, parameter :: mu = 1.4, one = 1.0 31c4762a1bSJed Brown ! 32c4762a1bSJed Brown dfdt_vdp(1, :, :, :) = f(2, 1, 1, 1) 33c4762a1bSJed Brown dfdt_vdp(2, :, :, :) = mu*(one - f(1, 1, 1, 1)**2)*f(2, 1, 1, 1) - f(1, 1, 1, 1) 34c4762a1bSJed Brown end function dfdt_vdp 35c4762a1bSJed Brown ! 36c4762a1bSJed Brown ! The standard Forward Euler time-stepping method. 37c4762a1bSJed Brown ! 38c4762a1bSJed Brown recursive subroutine forw_euler(t, dt, ib1, ibn, jb1, jbn, kb1, kbn, imax, jmax, kmax, neq, y, dfdt) 39c4762a1bSJed Brown PetscReal, intent(in) :: t, dt 40c4762a1bSJed Brown PetscInt, intent(in) :: ib1, ibn, jb1, jbn, kb1, kbn, imax, jmax, kmax, neq 41c4762a1bSJed Brown PetscReal, dimension(neq, ib1:ibn, jb1:jbn, kb1:kbn), intent(inout) :: y 42c4762a1bSJed Brown ! 43c4762a1bSJed Brown ! Define the right-hand side function 44c4762a1bSJed Brown ! 45c4762a1bSJed Brown interface 46c4762a1bSJed Brown function dfdt(t, dt, ib1, ibn, jb1, jbn, kb1, kbn, imax, jmax, kmax, n, f) 47fe66ebccSMartin Diehl use petscsys 48c4762a1bSJed Brown PetscReal, intent(in) :: t, dt 49c4762a1bSJed Brown PetscInt, intent(in) :: ib1, ibn, jb1, jbn, kb1, kbn, imax, jmax, kmax, n 50c4762a1bSJed Brown PetscReal, dimension(n, ib1:ibn, jb1:jbn, kb1:kbn), intent(inout) :: f 51c4762a1bSJed Brown PetscReal, dimension(n, imax, jmax, kmax) :: dfdt 52c4762a1bSJed Brown end function dfdt 53c4762a1bSJed Brown end interface 54c4762a1bSJed Brown !-------------------------------------------------------------------------- 55c4762a1bSJed Brown ! 56c4762a1bSJed Brown y(:, 1:imax, 1:jmax, 1:kmax) = y(:, 1:imax, 1:jmax, 1:kmax) + dt*dfdt(t, dt, ib1, ibn, jb1, jbn, kb1, kbn, imax, jmax, kmax, neq, y) 57c4762a1bSJed Brown end subroutine forw_euler 58c4762a1bSJed Brown ! 59c4762a1bSJed Brown ! The following 4 subroutines handle the mapping of coordinates. I'll explain 60c4762a1bSJed Brown ! this in detail: 61c4762a1bSJed Brown ! PETSc gives you local arrays which are indexed using the global indices. 62c4762a1bSJed Brown ! This is probably handy in some cases, but when you are re-writing an 63c4762a1bSJed Brown ! existing serial code and want to use DMDAs, you have tons of loops going 64c4762a1bSJed Brown ! from 1 to imax etc. that you don't want to change. 65c4762a1bSJed Brown ! These subroutines re-map the arrays so that all the local arrays go from 66c4762a1bSJed Brown ! 1 to the (local) imax. 67c4762a1bSJed Brown ! 68c4762a1bSJed Brown subroutine petsc_to_local(da, vec, array, f, dof, stw) 69c4762a1bSJed Brown use petscdmda 70c4762a1bSJed Brown DM :: da 71c4762a1bSJed Brown Vec, intent(in) :: vec 72c4762a1bSJed Brown PetscReal, pointer :: array(:, :, :, :) 73c4762a1bSJed Brown PetscInt, intent(in) :: dof, stw 74c4762a1bSJed Brown PetscReal, intent(inout), dimension(:, 1 - stw:, 1 - stw:, 1 - stw:) :: f 75c4762a1bSJed Brown PetscErrorCode :: ierr 76c4762a1bSJed Brown ! 77ce78bad3SBarry Smith PetscCall(DMDAVecGetArray(da, vec, array, ierr)) 78c4762a1bSJed Brown call transform_petsc_us(array, f, stw) 79c4762a1bSJed Brown end subroutine petsc_to_local 80c4762a1bSJed Brown subroutine transform_petsc_us(array, f, stw) 81c4762a1bSJed Brown !Note: this assumed shape-array is what does the "coordinate transformation" 82c4762a1bSJed Brown PetscInt, intent(in) :: stw 83c4762a1bSJed Brown PetscReal, intent(in), dimension(:, 1 - stw:, 1 - stw:, 1 - stw:) :: array 84c4762a1bSJed Brown PetscReal, intent(inout), dimension(:, 1 - stw:, 1 - stw:, 1 - stw:) :: f 85c4762a1bSJed Brown f(:, :, :, :) = array(:, :, :, :) 86c4762a1bSJed Brown end subroutine transform_petsc_us 87c4762a1bSJed Brown subroutine local_to_petsc(da, vec, array, f, dof, stw) 88c4762a1bSJed Brown use petscdmda 89c4762a1bSJed Brown DM :: da 90c4762a1bSJed Brown Vec, intent(inout) :: vec 91c4762a1bSJed Brown PetscReal, pointer :: array(:, :, :, :) 92c4762a1bSJed Brown PetscInt, intent(in) :: dof, stw 93c4762a1bSJed Brown PetscReal, intent(inout), dimension(:, 1 - stw:, 1 - stw:, 1 - stw:) :: f 94c4762a1bSJed Brown PetscErrorCode :: ierr 95c4762a1bSJed Brown call transform_us_petsc(array, f, stw) 96ce78bad3SBarry Smith PetscCall(DMDAVecRestoreArray(da, vec, array, ierr)) 97c4762a1bSJed Brown end subroutine local_to_petsc 98c4762a1bSJed Brown subroutine transform_us_petsc(array, f, stw) 99c4762a1bSJed Brown !Note: this assumed shape-array is what does the "coordinate transformation" 100c4762a1bSJed Brown PetscInt, intent(in) :: stw 101c4762a1bSJed Brown PetscReal, intent(inout), dimension(:, 1 - stw:, 1 - stw:, 1 - stw:) :: array 102c4762a1bSJed Brown PetscReal, intent(in), dimension(:, 1 - stw:, 1 - stw:, 1 - stw:) :: f 103c4762a1bSJed Brown array(:, :, :, :) = f(:, :, :, :) 104c4762a1bSJed Brown end subroutine transform_us_petsc 10577d968b7SBarry Smithend module ex13f90auxmodule 106