Actual source code: ex302k.kokkos.cxx

  1: static char help[] = "Testing MatCreateSeqAIJKokkosWithKokkosViews() and various read/write Kokkos view APIs on the device.\n\n";

  3: #include <petsc_kokkos.hpp>
  4: #include <petscvec_kokkos.hpp>
  5: #include <petscdevice.h>
  6: #include <petscmat.h>
  7: #include <petscmat_kokkos.hpp>
  8: #include <Kokkos_Core.hpp>
  9: #include <Kokkos_DualView.hpp>

 11: using HostMirrorMemorySpace = Kokkos::DualView<PetscScalar *>::host_mirror_space::memory_space;

 13: int main(int argc, char **argv)
 14: {
 15:   Mat             A, B, BT;
 16:   PetscInt        i, j, column, M, N, m, n, m_ab, n_ab;
 17:   PetscInt       *di, *dj, *oi, *oj, nd;
 18:   const PetscInt *garray;
 19:   PetscInt       *garray_h;
 20:   PetscScalar    *oa, *da;
 21:   PetscScalar     value;
 22:   PetscRandom     rctx;
 23:   PetscBool       equal, done;
 24:   Mat             AA, AB;
 25:   PetscMPIInt     size, rank;

 27:   // ~~~~~~~~~~~~~~~~~~~~~
 28:   // This test shows the routines needed to build a kokkos matrix without preallocation
 29:   // on the host
 30:   // ~~~~~~~~~~~~~~~~~~~~~

 32:   PetscFunctionBeginUser;
 33:   PetscCall(PetscInitialize(&argc, &argv, NULL, help));
 34:   PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD, &size));
 35:   PetscCheck(size > 1, PETSC_COMM_WORLD, PETSC_ERR_WRONG_MPI_SIZE, "Must run with 2 or more processes");
 36:   PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank));

 38:   /* Create a mpiaij matrix for checking */
 39:   PetscCall(MatCreateAIJ(PETSC_COMM_WORLD, 5, 5, PETSC_DECIDE, PETSC_DECIDE, 0, NULL, 0, NULL, &A));
 40:   PetscCall(MatSetFromOptions(A));
 41:   PetscCall(MatSetOption(A, MAT_NEW_NONZERO_LOCATION_ERR, PETSC_FALSE));
 42:   PetscCall(MatSetUp(A));
 43:   PetscCall(PetscRandomCreate(PETSC_COMM_WORLD, &rctx));
 44:   PetscCall(PetscRandomSetFromOptions(rctx));

 46:   for (i = 5 * rank; i < 5 * rank + 5; i++) {
 47:     for (j = 0; j < 5 * size; j++) {
 48:       PetscCall(PetscRandomGetValue(rctx, &value));
 49:       column = (PetscInt)(5 * size * PetscRealPart(value));

 51:       // rank 0 has no off-process entries
 52:       if (rank == 0 && (column < i || column >= i)) column = i;

 54:       PetscCall(PetscRandomGetValue(rctx, &value));
 55:       PetscCall(MatSetValues(A, 1, &i, 1, &column, &value, INSERT_VALUES));
 56:     }
 57:   }
 58:   PetscCall(MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY));
 59:   PetscCall(MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY));

 61:   PetscCall(MatGetSize(A, &M, &N));
 62:   PetscCall(MatGetLocalSize(A, &m, &n));
 63:   PetscCall(MatMPIAIJGetSeqAIJ(A, &AA, &AB, &garray));
 64:   PetscCall(MatGetRowIJ(AA, 0, PETSC_FALSE, PETSC_FALSE, &nd, (const PetscInt **)&di, (const PetscInt **)&dj, &done));
 65:   PetscCall(MatSeqAIJGetArray(AA, &da));
 66:   PetscCall(MatGetRowIJ(AB, 0, PETSC_FALSE, PETSC_FALSE, &nd, (const PetscInt **)&oi, (const PetscInt **)&oj, &done));
 67:   PetscCall(MatSeqAIJGetArray(AB, &oa));
 68:   PetscCall(MatGetSize(AB, &m_ab, &n_ab));

 70:   Mat output_mat_local, output_mat_nonlocal;
 71:   // Be careful about scope given the kokkos memory reference counts
 72:   {
 73:     // Local
 74:     Kokkos::View<PetscScalar *> a_local_d;
 75:     Kokkos::View<PetscInt *>    i_local_d;
 76:     Kokkos::View<PetscInt *>    j_local_d;

 78:     // Nonlocal
 79:     Kokkos::View<PetscScalar *> a_nonlocal_d;
 80:     Kokkos::View<PetscInt *>    i_nonlocal_d;
 81:     Kokkos::View<PetscInt *>    j_nonlocal_d;

 83:     // Create device memory
 84:     PetscCallCXX(a_local_d = Kokkos::View<PetscScalar *>("a_local_d", di[5]));
 85:     PetscCallCXX(i_local_d = Kokkos::View<PetscInt *>("i_local_d", m + 1));
 86:     PetscCallCXX(j_local_d = Kokkos::View<PetscInt *>("j_local_d", di[5]));

 88:     // Create non-local device memory
 89:     PetscCallCXX(a_nonlocal_d = Kokkos::View<PetscScalar *>("a_nonlocal_d", oi[5]));
 90:     PetscCallCXX(i_nonlocal_d = Kokkos::View<PetscInt *>("i_nonlocal_d", m + 1));
 91:     PetscCallCXX(j_nonlocal_d = Kokkos::View<PetscInt *>("j_nonlocal_d", oi[5]));

 93:     // ~~~~~~~~~~~~~~~~~~~~~
 94:     // Could fill the aij on the device - we're just going to test
 95:     // by copying in the existing host values
 96:     // ~~~~~~~~~~~~~~~~~~~~~
 97:     Kokkos::View<PetscScalar *, HostMirrorMemorySpace> a_local_h;
 98:     Kokkos::View<PetscInt *, HostMirrorMemorySpace>    i_local_h;
 99:     Kokkos::View<PetscInt *, HostMirrorMemorySpace>    j_local_h;
100:     Kokkos::View<PetscScalar *, HostMirrorMemorySpace> a_nonlocal_h;
101:     Kokkos::View<PetscInt *, HostMirrorMemorySpace>    i_nonlocal_h;
102:     Kokkos::View<PetscInt *, HostMirrorMemorySpace>    j_nonlocal_h;

104:     PetscCallCXX(a_local_h = Kokkos::View<PetscScalar *, HostMirrorMemorySpace>(da, di[5]));
105:     PetscCallCXX(i_local_h = Kokkos::View<PetscInt *, HostMirrorMemorySpace>(di, m + 1));
106:     PetscCallCXX(j_local_h = Kokkos::View<PetscInt *, HostMirrorMemorySpace>(dj, di[5]));
107:     PetscCallCXX(a_nonlocal_h = Kokkos::View<PetscScalar *, HostMirrorMemorySpace>(oa, oi[5]));
108:     PetscCallCXX(i_nonlocal_h = Kokkos::View<PetscInt *, HostMirrorMemorySpace>(oi, m + 1));
109:     PetscCallCXX(j_nonlocal_h = Kokkos::View<PetscInt *, HostMirrorMemorySpace>(oj, oi[5]));

111:     // Haven't specified an exec space so these will all be synchronous
112:     // and finish without a need to call fence after
113:     PetscCallCXX(Kokkos::deep_copy(a_local_d, a_local_h));
114:     PetscCallCXX(Kokkos::deep_copy(i_local_d, i_local_h));
115:     PetscCallCXX(Kokkos::deep_copy(j_local_d, j_local_h));
116:     PetscCallCXX(Kokkos::deep_copy(a_nonlocal_d, a_nonlocal_h));
117:     PetscCallCXX(Kokkos::deep_copy(i_nonlocal_d, i_nonlocal_h));
118:     PetscCallCXX(Kokkos::deep_copy(j_nonlocal_d, j_nonlocal_h));

120:     // The garray passed in has to be on the host, but it can be created
121:     // on device and copied to the host
122:     // We're just going to copy the existing host values here
123:     PetscCall(PetscMalloc1(n_ab, &garray_h));
124:     for (int i = 0; i < n_ab; i++) garray_h[i] = garray[i];

126:     // ~~~~~~~~~~~~~~~~~~~~~

128:     // ~~~~~~~~~~~~~~~~~
129:     // Test MatCreateSeqAIJKokkosWithKokkosViews
130:     // ~~~~~~~~~~~~~~~~~

132:     // We can create our local diagonal block matrix directly on the device
133:     PetscCall(MatCreateSeqAIJKokkosWithKokkosViews(PETSC_COMM_SELF, m, n, i_local_d, j_local_d, a_local_d, &output_mat_local));

135:     // We can create our nonlocal diagonal block matrix directly on the device
136:     PetscCall(MatCreateSeqAIJKokkosWithKokkosViews(PETSC_COMM_SELF, m, n_ab, i_nonlocal_d, j_nonlocal_d, a_nonlocal_d, &output_mat_nonlocal));

138:     // Build our MPI matrix
139:     // If we provide garray and output_mat_nonlocal with local indices and the compactified size
140:     // almost nothing happens on the host
141:     PetscCall(MatCreateMPIAIJWithSeqAIJ(PETSC_COMM_WORLD, M, N, output_mat_local, output_mat_nonlocal, garray_h, &B));

143:     PetscCall(MatEqual(A, B, &equal));
144:     PetscCall(MatRestoreRowIJ(AA, 0, PETSC_FALSE, PETSC_FALSE, &nd, (const PetscInt **)&di, (const PetscInt **)&dj, &done));
145:     PetscCall(MatSeqAIJRestoreArray(AA, &da));
146:     PetscCall(MatRestoreRowIJ(AB, 0, PETSC_FALSE, PETSC_FALSE, &nd, (const PetscInt **)&oi, (const PetscInt **)&oj, &done));
147:     PetscCall(MatSeqAIJRestoreArray(AB, &oa));
148:     PetscCheck(equal, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Likely a bug in MatCreateSeqAIJKokkosWithKokkosViews()");

150:     // ~~~~~~~~~~~~~~~~~
151:     // Test MatSeqAIJ{Get,Restore}KokkosView{,Write}
152:     // ~~~~~~~~~~~~~~~~~

154:     PetscReal   norm_before, norm_after;
155:     PetscInt    nnz_AA   = 0;
156:     PetscScalar host_sum = 0.0;

158:     PetscCall(MatNorm(AA, NORM_FROBENIUS, &norm_before));

160:     /* Const overload: read-only access. Sum the values and check it matches a host-side reference. */
161:     {
162:       Kokkos::View<const PetscScalar *> ro_view;
163:       PetscCall(MatSeqAIJGetKokkosView(AA, &ro_view));
164:       nnz_AA = (PetscInt)ro_view.extent(0);

166:       PetscScalar device_sum = 0.0;
167:       Kokkos::parallel_reduce("ex302k_sum", Kokkos::RangePolicy<>(PetscGetKokkosExecutionSpace(), 0, nnz_AA), KOKKOS_LAMBDA(const PetscInt k, PetscScalar &lsum) { lsum += ro_view(k); }, device_sum);

169:       const PetscScalar *aa_host;
170:       PetscCall(MatSeqAIJGetArrayRead(AA, &aa_host));
171:       for (PetscInt k = 0; k < nnz_AA; k++) host_sum += aa_host[k];
172:       PetscCall(MatSeqAIJRestoreArrayRead(AA, &aa_host));

174:       PetscCheck(PetscAbsScalar(device_sum - host_sum) <= PETSC_SMALL * PetscAbsScalar(host_sum), PETSC_COMM_SELF, PETSC_ERR_PLIB, "MatSeqAIJGetKokkosView (const) device/host mismatch");
175:       PetscCall(MatSeqAIJRestoreKokkosView(AA, &ro_view));
176:     }

178:     /* Snapshot the original values into a host Kokkos view so we can restore them later via the write-only overload. */
179:     Kokkos::View<PetscScalar *, HostMirrorMemorySpace> saved_h("saved_h", nnz_AA);
180:     {
181:       const PetscScalar *aa_host;
182:       PetscCall(MatSeqAIJGetArrayRead(AA, &aa_host));
183:       for (PetscInt k = 0; k < nnz_AA; k++) saved_h(k) = aa_host[k];
184:       PetscCall(MatSeqAIJRestoreArrayRead(AA, &aa_host));
185:     }

187:     /* Write-only overload: overwrite all entries with zero (no read of the prior contents). */
188:     {
189:       Kokkos::View<PetscScalar *> rw_view;
190:       PetscCall(MatSeqAIJGetKokkosViewWrite(AA, &rw_view));
191:       PetscCallCXX(Kokkos::deep_copy(rw_view, (PetscScalar)0.0));
192:       PetscCall(MatSeqAIJRestoreKokkosViewWrite(AA, &rw_view));
193:     }
194:     {
195:       PetscReal norm_zero;
196:       PetscCall(MatNorm(AA, NORM_FROBENIUS, &norm_zero));
197:       PetscCheck(norm_zero == 0.0, PETSC_COMM_SELF, PETSC_ERR_PLIB, "MatSeqAIJ{Get,Restore}KokkosViewWrite did not propagate device write");
198:     }

200:     /* Write-only overload again: restore the original values from the host snapshot. */
201:     {
202:       Kokkos::View<PetscScalar *> rw_view;
203:       PetscCall(MatSeqAIJGetKokkosViewWrite(AA, &rw_view));
204:       PetscCallCXX(Kokkos::deep_copy(rw_view, saved_h));
205:       PetscCall(MatSeqAIJRestoreKokkosViewWrite(AA, &rw_view));
206:     }

208:     /* Read-write overload: scale by 2, then by 1/2 to undo. */
209:     {
210:       Kokkos::View<PetscScalar *> rw_view;
211:       PetscCall(MatSeqAIJGetKokkosView(AA, &rw_view));
212:       // It seems with SYCL, the user code has to use the same execution space as PETSc's. MatNorm() will sync the execution space before accessing data on host
213:       Kokkos::parallel_for("ex302k_scale_up", Kokkos::RangePolicy<>(PetscGetKokkosExecutionSpace(), 0, nnz_AA), KOKKOS_LAMBDA(const PetscInt k) { rw_view(k) *= (PetscScalar)2.0; });
214:       PetscCall(MatSeqAIJRestoreKokkosView(AA, &rw_view));
215:     }
216:     {
217:       Kokkos::View<PetscScalar *> rw_view;
218:       PetscCall(MatSeqAIJGetKokkosView(AA, &rw_view));
219:       Kokkos::parallel_for("ex302k_scale_down", Kokkos::RangePolicy<>(PetscGetKokkosExecutionSpace(), 0, nnz_AA), KOKKOS_LAMBDA(const PetscInt k) { rw_view(k) *= (PetscScalar)0.5; });
220:       PetscCall(MatSeqAIJRestoreKokkosView(AA, &rw_view));
221:     }

223:     PetscCall(MatNorm(AA, NORM_FROBENIUS, &norm_after));
224:     PetscCheck(PetscAbsReal(norm_after - norm_before) <= PETSC_SMALL * norm_before, PETSC_COMM_SELF, PETSC_ERR_PLIB, "MatSeqAIJ{Get,Restore}KokkosView round trip changed AA");
225:   }

227:   PetscCall(MatTranspose(B, MAT_INITIAL_MATRIX, &BT));

229:   /* Free spaces */
230:   PetscCall(PetscRandomDestroy(&rctx));
231:   PetscCall(MatDestroy(&A));
232:   PetscCall(MatDestroy(&B));
233:   PetscCall(MatDestroy(&BT));
234:   PetscCall(PetscFinalize());
235:   return 0;
236: }

238: /*TEST
239:   build:
240:     requires: kokkos_kernels

242:   test:
243:     nsize: 2
244:     args: -mat_type aijkokkos
245:     requires: kokkos_kernels
246:     output_file: output/empty.out

248: TEST*/