Actual source code: util.c
1: /*
2: GAMG geometric-algebric multigrid PC - Mark Adams 2011
3: */
4: #include <petsc/private/matimpl.h>
5: #include <../src/ksp/pc/impls/gamg/gamg.h>
6: #include <petsc/private/kspimpl.h>
8: // PetscClangLinter pragma disable: -fdoc-sowing-chars
9: /*
10: PCGAMGGetDataWithGhosts - Get array of local + ghost data with local data
11: hacks into Mat MPIAIJ so this must have size > 1
13: Input Parameters:
14: + Gmat - MPIAIJ matrix for scatters
15: . data_sz - number of data terms per node (# cols in output)
16: - data_in - column-oriented local data of size nloc*data_sz
18: Output Parameters:
19: + a_stride - number of rows of output (locals+ghosts)
20: - a_data_out - output data with ghosts of size stride*data_sz
22: */
23: PetscErrorCode PCGAMGGetDataWithGhosts(Mat Gmat, PetscInt data_sz, PetscReal data_in[], PetscInt *a_stride, PetscReal **a_data_out)
24: {
25: Vec tmp_crds;
26: Mat_MPIAIJ *mpimat;
27: PetscInt nnodes, num_ghosts, dir, kk, jj, my0, Iend, nloc;
28: PetscScalar *data_arr;
29: PetscReal *datas;
30: PetscBool isMPIAIJ;
32: PetscFunctionBegin;
34: mpimat = (Mat_MPIAIJ *)Gmat->data;
35: PetscCall(PetscObjectBaseTypeCompare((PetscObject)Gmat, MATMPIAIJ, &isMPIAIJ));
36: PetscCall(MatGetOwnershipRange(Gmat, &my0, &Iend));
37: nloc = Iend - my0;
38: PetscCall(VecGetLocalSize(mpimat->lvec, &num_ghosts));
39: nnodes = num_ghosts + nloc;
40: *a_stride = nnodes;
41: PetscCall(MatCreateVecs(Gmat, &tmp_crds, NULL));
43: PetscCall(PetscMalloc1(data_sz * nnodes, &datas));
44: for (dir = 0; dir < data_sz; dir++) {
45: /* set local, and global */
46: for (kk = 0; kk < nloc; kk++) {
47: PetscInt gid = my0 + kk;
48: PetscScalar crd = data_in[dir * nloc + kk]; /* col oriented */
49: datas[dir * nnodes + kk] = PetscRealPart(crd); // get local part now
51: PetscCall(VecSetValues(tmp_crds, 1, &gid, &crd, INSERT_VALUES));
52: }
53: PetscCall(VecAssemblyBegin(tmp_crds));
54: PetscCall(VecAssemblyEnd(tmp_crds));
55: /* scatter / gather ghost data and add to end of output data */
56: PetscCall(VecScatterBegin(mpimat->Mvctx, tmp_crds, mpimat->lvec, INSERT_VALUES, SCATTER_FORWARD));
57: PetscCall(VecScatterEnd(mpimat->Mvctx, tmp_crds, mpimat->lvec, INSERT_VALUES, SCATTER_FORWARD));
58: PetscCall(VecGetArray(mpimat->lvec, &data_arr));
59: for (kk = nloc, jj = 0; jj < num_ghosts; kk++, jj++) datas[dir * nnodes + kk] = PetscRealPart(data_arr[jj]);
60: PetscCall(VecRestoreArray(mpimat->lvec, &data_arr));
61: }
62: PetscCall(VecDestroy(&tmp_crds));
63: *a_data_out = datas;
64: PetscFunctionReturn(PETSC_SUCCESS);
65: }