1c4762a1bSJed Brown /* 2c4762a1bSJed Brown * 3c4762a1bSJed Brown * Created on: Sep 25, 2017 4c4762a1bSJed Brown * Author: Fande Kong 5c4762a1bSJed Brown */ 6c4762a1bSJed Brown 7c4762a1bSJed Brown static char help[] = "Illustrate the use of MatResetPreallocation.\n"; 8c4762a1bSJed Brown 9c4762a1bSJed Brown #include "petscmat.h" 10c4762a1bSJed Brown 119371c9d4SSatish Balay int main(int argc, char **argv) { 12c4762a1bSJed Brown Mat A; 13c4762a1bSJed Brown MPI_Comm comm; 14c4762a1bSJed Brown PetscInt n = 5, m = 5, *dnnz, *onnz, i, rstart, rend, M, N; 15c4762a1bSJed Brown 16327415f7SBarry Smith PetscFunctionBeginUser; 179566063dSJacob Faibussowitsch PetscCall(PetscInitialize(&argc, &argv, 0, help)); 18c4762a1bSJed Brown comm = MPI_COMM_WORLD; 199566063dSJacob Faibussowitsch PetscCall(PetscMalloc2(m, &dnnz, m, &onnz)); 20c4762a1bSJed Brown for (i = 0; i < m; i++) { 21c4762a1bSJed Brown dnnz[i] = 1; 22c4762a1bSJed Brown onnz[i] = 1; 23c4762a1bSJed Brown } 249566063dSJacob Faibussowitsch PetscCall(MatCreateAIJ(comm, m, n, PETSC_DETERMINE, PETSC_DETERMINE, PETSC_DECIDE, dnnz, PETSC_DECIDE, onnz, &A)); 259566063dSJacob Faibussowitsch PetscCall(MatSetFromOptions(A)); 269566063dSJacob Faibussowitsch PetscCall(MatSetUp(A)); 279566063dSJacob Faibussowitsch PetscCall(PetscFree2(dnnz, onnz)); 28c4762a1bSJed Brown 29c4762a1bSJed Brown /* This assembly shrinks memory because we do not insert enough number of values */ 309566063dSJacob Faibussowitsch PetscCall(MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY)); 319566063dSJacob Faibussowitsch PetscCall(MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY)); 32c4762a1bSJed Brown 33c4762a1bSJed Brown /* MatResetPreallocation restores the memory required by users */ 349566063dSJacob Faibussowitsch PetscCall(MatResetPreallocation(A)); 359566063dSJacob Faibussowitsch PetscCall(MatSetOption(A, MAT_NEW_NONZERO_ALLOCATION_ERR, PETSC_TRUE)); 369566063dSJacob Faibussowitsch PetscCall(MatGetOwnershipRange(A, &rstart, &rend)); 379566063dSJacob Faibussowitsch PetscCall(MatGetSize(A, &M, &N)); 38c4762a1bSJed Brown for (i = rstart; i < rend; i++) { 399566063dSJacob Faibussowitsch PetscCall(MatSetValue(A, i, i, 2.0, INSERT_VALUES)); 40*48a46eb9SPierre Jolivet if (rend < N) PetscCall(MatSetValue(A, i, rend, 1.0, INSERT_VALUES)); 41c4762a1bSJed Brown } 429566063dSJacob Faibussowitsch PetscCall(MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY)); 439566063dSJacob Faibussowitsch PetscCall(MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY)); 449566063dSJacob Faibussowitsch PetscCall(MatView(A, PETSC_VIEWER_STDOUT_WORLD)); 459566063dSJacob Faibussowitsch PetscCall(MatDestroy(&A)); 469566063dSJacob Faibussowitsch PetscCall(PetscFinalize()); 47b122ec5aSJacob Faibussowitsch return 0; 48c4762a1bSJed Brown } 49c4762a1bSJed Brown 50c4762a1bSJed Brown /*TEST 51c4762a1bSJed Brown 52c4762a1bSJed Brown test: 53c4762a1bSJed Brown suffix: 1 54c4762a1bSJed Brown 55c4762a1bSJed Brown test: 56c4762a1bSJed Brown suffix: 2 57c4762a1bSJed Brown nsize: 2 58c4762a1bSJed Brown 59c4762a1bSJed Brown TEST*/ 60