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 11c4762a1bSJed Brown int main(int argc,char **argv) 12c4762a1bSJed Brown { 13c4762a1bSJed Brown Mat A; 14c4762a1bSJed Brown MPI_Comm comm; 15c4762a1bSJed Brown PetscInt n=5,m=5,*dnnz,*onnz,i,rstart,rend,M,N; 16c4762a1bSJed Brown PetscErrorCode ierr; 17c4762a1bSJed Brown 18c4762a1bSJed Brown ierr = PetscInitialize(&argc,&argv,0,help);if (ierr) return ierr; 19c4762a1bSJed Brown comm = MPI_COMM_WORLD; 20*5f80ce2aSJacob Faibussowitsch CHKERRQ(PetscMalloc2(m,&dnnz,m,&onnz)); 21c4762a1bSJed Brown for (i=0; i<m; i++) { 22c4762a1bSJed Brown dnnz[i] = 1; 23c4762a1bSJed Brown onnz[i] = 1; 24c4762a1bSJed Brown } 25*5f80ce2aSJacob Faibussowitsch CHKERRQ(MatCreateAIJ(comm,m,n,PETSC_DETERMINE,PETSC_DETERMINE,PETSC_DECIDE,dnnz,PETSC_DECIDE,onnz,&A)); 26*5f80ce2aSJacob Faibussowitsch CHKERRQ(MatSetFromOptions(A)); 27*5f80ce2aSJacob Faibussowitsch CHKERRQ(MatSetUp(A)); 28*5f80ce2aSJacob Faibussowitsch CHKERRQ(PetscFree2(dnnz,onnz)); 29c4762a1bSJed Brown 30c4762a1bSJed Brown /* This assembly shrinks memory because we do not insert enough number of values */ 31*5f80ce2aSJacob Faibussowitsch CHKERRQ(MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY)); 32*5f80ce2aSJacob Faibussowitsch CHKERRQ(MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY)); 33c4762a1bSJed Brown 34c4762a1bSJed Brown /* MatResetPreallocation restores the memory required by users */ 35*5f80ce2aSJacob Faibussowitsch CHKERRQ(MatResetPreallocation(A)); 36*5f80ce2aSJacob Faibussowitsch CHKERRQ(MatSetOption(A,MAT_NEW_NONZERO_ALLOCATION_ERR,PETSC_TRUE)); 37*5f80ce2aSJacob Faibussowitsch CHKERRQ(MatGetOwnershipRange(A,&rstart,&rend)); 38*5f80ce2aSJacob Faibussowitsch CHKERRQ(MatGetSize(A,&M,&N)); 39c4762a1bSJed Brown for (i=rstart; i<rend; i++) { 40*5f80ce2aSJacob Faibussowitsch CHKERRQ(MatSetValue(A,i,i,2.0,INSERT_VALUES)); 41c4762a1bSJed Brown if (rend<N) { 42*5f80ce2aSJacob Faibussowitsch CHKERRQ(MatSetValue(A,i,rend,1.0,INSERT_VALUES)); 43c4762a1bSJed Brown } 44c4762a1bSJed Brown } 45*5f80ce2aSJacob Faibussowitsch CHKERRQ(MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY)); 46*5f80ce2aSJacob Faibussowitsch CHKERRQ(MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY)); 47*5f80ce2aSJacob Faibussowitsch CHKERRQ(MatView(A,PETSC_VIEWER_STDOUT_WORLD)); 48*5f80ce2aSJacob Faibussowitsch CHKERRQ(MatDestroy(&A)); 49c4762a1bSJed Brown ierr = PetscFinalize(); 50c4762a1bSJed Brown return ierr; 51c4762a1bSJed Brown } 52c4762a1bSJed Brown 53c4762a1bSJed Brown /*TEST 54c4762a1bSJed Brown 55c4762a1bSJed Brown test: 56c4762a1bSJed Brown suffix: 1 57c4762a1bSJed Brown 58c4762a1bSJed Brown test: 59c4762a1bSJed Brown suffix: 2 60c4762a1bSJed Brown nsize: 2 61c4762a1bSJed Brown 62c4762a1bSJed Brown TEST*/ 63