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          = (PetscScalar)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: }

 67: PetscErrorCode PCGAMGHashTableCreate(PetscInt a_size, PCGAMGHashTable *a_tab)
 68: {
 69:   PetscInt kk;

 71:   PetscFunctionBegin;
 72:   a_tab->size = a_size;
 73:   PetscCall(PetscMalloc2(a_size, &a_tab->table, a_size, &a_tab->data));
 74:   for (kk = 0; kk < a_size; kk++) a_tab->table[kk] = -1;
 75:   PetscFunctionReturn(PETSC_SUCCESS);
 76: }

 78: PetscErrorCode PCGAMGHashTableDestroy(PCGAMGHashTable *a_tab)
 79: {
 80:   PetscFunctionBegin;
 81:   PetscCall(PetscFree2(a_tab->table, a_tab->data));
 82:   PetscFunctionReturn(PETSC_SUCCESS);
 83: }

 85: PetscErrorCode PCGAMGHashTableAdd(PCGAMGHashTable *a_tab, PetscInt a_key, PetscInt a_data)
 86: {
 87:   PetscInt kk, idx;

 89:   PetscFunctionBegin;
 90:   PetscCheck(a_key >= 0, PETSC_COMM_SELF, PETSC_ERR_USER, "Negative key %" PetscInt_FMT ".", a_key);
 91:   for (kk = 0, idx = GAMG_HASH(a_key); kk < a_tab->size; kk++, idx = (idx == (a_tab->size - 1)) ? 0 : idx + 1) {
 92:     if (a_tab->table[idx] == a_key) {
 93:       /* exists */
 94:       a_tab->data[idx] = a_data;
 95:       break;
 96:     } else if (a_tab->table[idx] == -1) {
 97:       /* add */
 98:       a_tab->table[idx] = a_key;
 99:       a_tab->data[idx]  = a_data;
100:       break;
101:     }
102:   }
103:   if (kk == a_tab->size) {
104:     /* this is not to efficient, waiting until completely full */
105:     PetscInt oldsize = a_tab->size, new_size = 2 * a_tab->size + 5, *oldtable = a_tab->table, *olddata = a_tab->data;

107:     a_tab->size = new_size;
108:     PetscCall(PetscMalloc2(a_tab->size, &a_tab->table, a_tab->size, &a_tab->data));
109:     for (kk = 0; kk < a_tab->size; kk++) a_tab->table[kk] = -1;
110:     for (kk = 0; kk < oldsize; kk++) {
111:       if (oldtable[kk] != -1) PetscCall(PCGAMGHashTableAdd(a_tab, oldtable[kk], olddata[kk]));
112:     }
113:     PetscCall(PetscFree2(oldtable, olddata));
114:     PetscCall(PCGAMGHashTableAdd(a_tab, a_key, a_data));
115:   }
116:   PetscFunctionReturn(PETSC_SUCCESS);
117: }