Actual source code: ex15.c
2: static char help[] = "Tests MatNorm(), MatLUFactor(), MatSolve() and MatSolveAdd().\n\n";
4: #include <petscmat.h>
6: int main(int argc,char **args)
7: {
8: Mat C;
9: PetscInt i,j,m = 3,n = 3,Ii,J;
10: PetscBool flg;
11: PetscScalar v;
12: IS perm,iperm;
13: Vec x,u,b,y;
14: PetscReal norm,tol=PETSC_SMALL;
15: MatFactorInfo info;
16: PetscMPIInt size;
18: PetscInitialize(&argc,&args,(char*)0,help);
19: MPI_Comm_size(PETSC_COMM_WORLD,&size);
21: MatCreate(PETSC_COMM_WORLD,&C);
22: MatSetSizes(C,PETSC_DECIDE,PETSC_DECIDE,m*n,m*n);
23: MatSetFromOptions(C);
24: MatSetUp(C);
25: PetscOptionsHasName(NULL,NULL,"-symmetric",&flg);
26: if (flg) { /* Treat matrix as symmetric only if we set this flag */
27: MatSetOption(C,MAT_SYMMETRIC,PETSC_TRUE);
28: MatSetOption(C,MAT_SYMMETRY_ETERNAL,PETSC_TRUE);
29: }
31: /* Create the matrix for the five point stencil, YET AGAIN */
32: for (i=0; i<m; i++) {
33: for (j=0; j<n; j++) {
34: v = -1.0; Ii = j + n*i;
35: if (i>0) {J = Ii - n; MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);}
36: if (i<m-1) {J = Ii + n; MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);}
37: if (j>0) {J = Ii - 1; MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);}
38: if (j<n-1) {J = Ii + 1; MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);}
39: v = 4.0; MatSetValues(C,1,&Ii,1,&Ii,&v,INSERT_VALUES);
40: }
41: }
42: MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);
43: MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);
44: MatGetOrdering(C,MATORDERINGRCM,&perm,&iperm);
45: MatView(C,PETSC_VIEWER_STDOUT_WORLD);
46: ISView(perm,PETSC_VIEWER_STDOUT_SELF);
47: VecCreateSeq(PETSC_COMM_SELF,m*n,&u);
48: VecSet(u,1.0);
49: VecDuplicate(u,&x);
50: VecDuplicate(u,&b);
51: VecDuplicate(u,&y);
52: MatMult(C,u,b);
53: VecCopy(b,y);
54: VecScale(y,2.0);
56: MatNorm(C,NORM_FROBENIUS,&norm);
57: PetscPrintf(PETSC_COMM_SELF,"Frobenius norm of matrix %g\n",(double)norm);
58: MatNorm(C,NORM_1,&norm);
59: PetscPrintf(PETSC_COMM_SELF,"One norm of matrix %g\n",(double)norm);
60: MatNorm(C,NORM_INFINITY,&norm);
61: PetscPrintf(PETSC_COMM_SELF,"Infinity norm of matrix %g\n",(double)norm);
63: MatFactorInfoInitialize(&info);
64: info.fill = 2.0;
65: info.dtcol = 0.0;
66: info.zeropivot = 1.e-14;
67: info.pivotinblocks = 1.0;
69: MatLUFactor(C,perm,iperm,&info);
71: /* Test MatSolve */
72: MatSolve(C,b,x);
73: VecView(b,PETSC_VIEWER_STDOUT_SELF);
74: VecView(x,PETSC_VIEWER_STDOUT_SELF);
75: VecAXPY(x,-1.0,u);
76: VecNorm(x,NORM_2,&norm);
77: if (norm > tol) {
78: PetscPrintf(PETSC_COMM_SELF,"MatSolve: Norm of error %g\n",(double)norm);
79: }
81: /* Test MatSolveAdd */
82: MatSolveAdd(C,b,y,x);
83: VecAXPY(x,-1.0,y);
84: VecAXPY(x,-1.0,u);
85: VecNorm(x,NORM_2,&norm);
86: if (norm > tol) {
87: PetscPrintf(PETSC_COMM_SELF,"MatSolveAdd(): Norm of error %g\n",(double)norm);
88: }
90: ISDestroy(&perm);
91: ISDestroy(&iperm);
92: VecDestroy(&u);
93: VecDestroy(&y);
94: VecDestroy(&b);
95: VecDestroy(&x);
96: MatDestroy(&C);
97: PetscFinalize();
98: return 0;
99: }
101: /*TEST
103: test:
105: TEST*/