1 2 static char help[] = "Tests the use of MatSolveTranspose().\n\n"; 3 4 #include <petscmat.h> 5 6 int main(int argc,char **args) 7 { 8 Mat C,A; 9 PetscInt i,j,m = 5,n = 5,Ii,J; 10 PetscScalar v,five = 5.0,one = 1.0; 11 IS isrow,row,col; 12 Vec x,u,b; 13 PetscReal norm; 14 MatFactorInfo info; 15 16 PetscCall(PetscInitialize(&argc,&args,(char*)0,help)); 17 PetscCall(PetscOptionsGetInt(NULL,NULL,"-m",&m,NULL)); 18 PetscCall(PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL)); 19 20 PetscCall(MatCreateSeqAIJ(PETSC_COMM_SELF,m*n,m*n,5,NULL,&C)); 21 PetscCall(MatSetUp(C)); 22 23 /* create the matrix for the five point stencil, YET AGAIN*/ 24 for (i=0; i<m; i++) { 25 for (j=0; j<n; j++) { 26 v = -1.0; Ii = j + n*i; 27 if (i>0) {J = Ii - n; PetscCall(MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES));} 28 if (i<m-1) {J = Ii + n; PetscCall(MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES));} 29 if (j>0) {J = Ii - 1; PetscCall(MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES));} 30 if (j<n-1) {J = Ii + 1; PetscCall(MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES));} 31 v = 4.0; PetscCall(MatSetValues(C,1,&Ii,1,&Ii,&v,INSERT_VALUES)); 32 } 33 } 34 PetscCall(MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY)); 35 PetscCall(MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY)); 36 37 PetscCall(ISCreateStride(PETSC_COMM_SELF,(m*n)/2,0,2,&isrow)); 38 PetscCall(MatZeroRowsIS(C,isrow,five,0,0)); 39 40 PetscCall(VecCreateSeq(PETSC_COMM_SELF,m*n,&u)); 41 PetscCall(VecDuplicate(u,&x)); 42 PetscCall(VecDuplicate(u,&b)); 43 PetscCall(VecSet(u,one)); 44 45 PetscCall(MatMultTranspose(C,u,b)); 46 47 /* Set default ordering to be Quotient Minimum Degree; also read 48 orderings from the options database */ 49 PetscCall(MatGetOrdering(C,MATORDERINGQMD,&row,&col)); 50 51 PetscCall(MatFactorInfoInitialize(&info)); 52 PetscCall(MatGetFactor(C,MATSOLVERPETSC,MAT_FACTOR_LU,&A)); 53 PetscCall(MatLUFactorSymbolic(A,C,row,col,&info)); 54 PetscCall(MatLUFactorNumeric(A,C,&info)); 55 PetscCall(MatSolveTranspose(A,b,x)); 56 57 PetscCall(ISView(row,PETSC_VIEWER_STDOUT_SELF)); 58 PetscCall(VecAXPY(x,-1.0,u)); 59 PetscCall(VecNorm(x,NORM_2,&norm)); 60 PetscCall(PetscPrintf(PETSC_COMM_SELF,"Norm of error %g\n",(double)norm)); 61 62 PetscCall(ISDestroy(&row)); 63 PetscCall(ISDestroy(&col)); 64 PetscCall(ISDestroy(&isrow)); 65 PetscCall(VecDestroy(&u)); 66 PetscCall(VecDestroy(&x)); 67 PetscCall(VecDestroy(&b)); 68 PetscCall(MatDestroy(&C)); 69 PetscCall(MatDestroy(&A)); 70 PetscCall(PetscFinalize()); 71 return 0; 72 } 73 74 /*TEST 75 76 test: 77 78 TEST*/ 79