xref: /petsc/src/mat/tests/ex185.c (revision df4cd43f92eaa320656440c40edb1046daee8f75)
1 static char help[] = "Tests MatCreateConstantDiagonal().\n"
2                      "\n";
3 
4 #include <petscmat.h>
5 
6 int main(int argc, char **args)
7 {
8   Vec       X, Y;
9   Mat       A, B, Af;
10   PetscBool flg;
11   PetscReal xnorm, ynorm, anorm;
12 
13   PetscFunctionBeginUser;
14   PetscCall(PetscInitialize(&argc, &args, (char *)0, help));
15 
16   PetscCall(MatCreateConstantDiagonal(PETSC_COMM_WORLD, PETSC_DETERMINE, PETSC_DETERMINE, 20, 20, 3.0, &A));
17   PetscCall(MatCreateVecs(A, &X, &Y));
18   PetscCall(MatView(A, PETSC_VIEWER_STDOUT_WORLD));
19 
20   PetscCall(VecSetRandom(X, NULL));
21   PetscCall(VecNorm(X, NORM_2, &xnorm));
22   PetscCall(MatMult(A, X, Y));
23   PetscCall(VecNorm(Y, NORM_2, &ynorm));
24   PetscCheck(PetscAbsReal(ynorm - 3 * xnorm) <= PETSC_SMALL, PETSC_COMM_WORLD, PETSC_ERR_PLIB, "Expected norm %g actual norm %g", (double)(3 * xnorm), (double)ynorm);
25   PetscCall(MatShift(A, 5.0));
26   PetscCall(MatScale(A, .5));
27   PetscCall(MatView(A, PETSC_VIEWER_STDOUT_WORLD));
28   PetscCall(MatNorm(A, NORM_FROBENIUS, &anorm));
29   PetscCheck(PetscAbsReal(anorm - 4.0) <= PETSC_SMALL, PETSC_COMM_WORLD, PETSC_ERR_PLIB, "Expected norm 4.0 actual norm %g", (double)anorm);
30 
31   /* Convert to AIJ (exercises MatGetRow/MatRestoreRow) */
32   PetscCall(MatConvert(A, MATAIJ, MAT_INITIAL_MATRIX, &B));
33   PetscCall(MatMultEqual(A, B, 10, &flg));
34   if (!flg) PetscCall(PetscPrintf(PETSC_COMM_WORLD, "Error MatMult\n"));
35   PetscCall(MatMultAddEqual(A, B, 10, &flg));
36   if (!flg) PetscCall(PetscPrintf(PETSC_COMM_WORLD, "Error MatMultAdd\n"));
37   PetscCall(MatMultTransposeEqual(A, B, 10, &flg));
38   if (!flg) PetscCall(PetscPrintf(PETSC_COMM_WORLD, "Error MatMultTranspose\n"));
39   PetscCall(MatMultTransposeAddEqual(A, B, 10, &flg));
40   if (!flg) PetscCall(PetscPrintf(PETSC_COMM_WORLD, "Error MatMultTransposeAdd\n"));
41 
42   PetscCall(MatGetDiagonal(A, Y));
43   PetscCall(MatGetFactor(A, MATSOLVERPETSC, MAT_FACTOR_LU, &Af));
44   PetscCall(MatLUFactorSymbolic(Af, A, NULL, NULL, NULL));
45   PetscCall(MatLUFactorNumeric(Af, A, NULL));
46   PetscCall(MatSolve(Af, X, Y));
47   PetscCall(VecNorm(Y, NORM_2, &ynorm));
48   PetscCheck(PetscAbsReal(ynorm - xnorm / 4) <= PETSC_SMALL, PETSC_COMM_WORLD, PETSC_ERR_PLIB, "Expected norm %g actual norm %g", (double)(.25 * xnorm), (double)ynorm);
49 
50   PetscCall(MatDestroy(&A));
51   PetscCall(MatDestroy(&B));
52   PetscCall(MatDestroy(&Af));
53   PetscCall(VecDestroy(&X));
54   PetscCall(VecDestroy(&Y));
55 
56   PetscCall(PetscFinalize());
57   return 0;
58 }
59 
60 /*TEST
61 
62   test:
63     nsize: 2
64 
65 TEST*/
66