xref: /petsc/src/mat/tests/ex185.c (revision 58d68138c660dfb4e9f5b03334792cd4f2ffd7cc)
1 static char help[] = "Tests MatCreateConstantDiagonal().\n"
2                      "\n";
3 
4 #include <petscmat.h>
5 
6 int main(int argc, char **args) {
7   Vec       X, Y;
8   Mat       A, B, Af;
9   PetscBool flg;
10   PetscReal xnorm, ynorm, anorm;
11 
12   PetscFunctionBeginUser;
13   PetscCall(PetscInitialize(&argc, &args, (char *)0, help));
14 
15   PetscCall(MatCreateConstantDiagonal(PETSC_COMM_WORLD, PETSC_DETERMINE, PETSC_DETERMINE, 20, 20, 3.0, &A));
16   PetscCall(MatCreateVecs(A, &X, &Y));
17   PetscCall(MatView(A, PETSC_VIEWER_STDOUT_WORLD));
18 
19   PetscCall(VecSetRandom(X, NULL));
20   PetscCall(VecNorm(X, NORM_2, &xnorm));
21   PetscCall(MatMult(A, X, Y));
22   PetscCall(VecNorm(Y, NORM_2, &ynorm));
23   PetscCheck(PetscAbsReal(ynorm - 3 * xnorm) <= PETSC_SMALL, PETSC_COMM_WORLD, PETSC_ERR_PLIB, "Expected norm %g actual norm %g", (double)(3 * xnorm), (double)ynorm);
24   PetscCall(MatShift(A, 5.0));
25   PetscCall(MatScale(A, .5));
26   PetscCall(MatView(A, PETSC_VIEWER_STDOUT_WORLD));
27   PetscCall(MatNorm(A, NORM_FROBENIUS, &anorm));
28   PetscCheck(PetscAbsReal(anorm - 4.0) <= PETSC_SMALL, PETSC_COMM_WORLD, PETSC_ERR_PLIB, "Expected norm 4.0 actual norm %g", (double)anorm);
29 
30   /* Convert to AIJ (exercises MatGetRow/MatRestoreRow) */
31   PetscCall(MatConvert(A, MATAIJ, MAT_INITIAL_MATRIX, &B));
32   PetscCall(MatMultEqual(A, B, 10, &flg));
33   if (!flg) PetscCall(PetscPrintf(PETSC_COMM_WORLD, "Error MatMult\n"));
34   PetscCall(MatMultAddEqual(A, B, 10, &flg));
35   if (!flg) PetscCall(PetscPrintf(PETSC_COMM_WORLD, "Error MatMultAdd\n"));
36   PetscCall(MatMultTransposeEqual(A, B, 10, &flg));
37   if (!flg) PetscCall(PetscPrintf(PETSC_COMM_WORLD, "Error MatMultTranspose\n"));
38   PetscCall(MatMultTransposeAddEqual(A, B, 10, &flg));
39   if (!flg) PetscCall(PetscPrintf(PETSC_COMM_WORLD, "Error MatMultTransposeAdd\n"));
40 
41   PetscCall(MatGetDiagonal(A, Y));
42   PetscCall(MatGetFactor(A, MATSOLVERPETSC, MAT_FACTOR_LU, &Af));
43   PetscCall(MatLUFactorSymbolic(Af, A, NULL, NULL, NULL));
44   PetscCall(MatLUFactorNumeric(Af, A, NULL));
45   PetscCall(MatSolve(Af, X, Y));
46   PetscCall(VecNorm(Y, NORM_2, &ynorm));
47   PetscCheck(PetscAbsReal(ynorm - xnorm / 4) <= PETSC_SMALL, PETSC_COMM_WORLD, PETSC_ERR_PLIB, "Expected norm %g actual norm %g", (double)(.25 * xnorm), (double)ynorm);
48 
49   PetscCall(MatDestroy(&A));
50   PetscCall(MatDestroy(&B));
51   PetscCall(MatDestroy(&Af));
52   PetscCall(VecDestroy(&X));
53   PetscCall(VecDestroy(&Y));
54 
55   PetscCall(PetscFinalize());
56   return 0;
57 }
58 
59 /*TEST
60 
61   test:
62     nsize: 2
63 
64 TEST*/
65