Actual source code: ex15.c
1: /*$Id: ex15.c,v 1.22 2001/08/07 21:30:08 bsmith Exp $*/
3: static char help[] = "Tests MatNorm(), MatLUFactor(), MatSolve() and MatSolveAdd().nn";
5: #include petscmat.h
7: int main(int argc,char **args)
8: {
9: Mat C;
10: int i,j,m = 3,n = 3,I,J,ierr;
11: PetscTruth flg;
12: PetscScalar v,mone = -1.0,one = 1.0,alpha = 2.0;
13: IS perm,iperm;
14: Vec x,u,b,y;
15: PetscReal norm;
17: PetscInitialize(&argc,&args,(char *)0,help);
19: MatCreate(PETSC_COMM_WORLD,PETSC_DECIDE,PETSC_DECIDE,m*n,m*n,&C);
20: MatSetFromOptions(C);
21: PetscOptionsHasName(PETSC_NULL,"-symmetric",&flg);
22: if (flg) { /* Treat matrix as symmetric only if we set this flag */
23: MatSetOption(C,MAT_SYMMETRIC);
24: }
26: /* Create the matrix for the five point stencil, YET AGAIN */
27: for (i=0; i<m; i++) {
28: for (j=0; j<n; j++) {
29: v = -1.0; I = j + n*i;
30: if (i>0) {J = I - n; MatSetValues(C,1,&I,1,&J,&v,INSERT_VALUES);}
31: if (i<m-1) {J = I + n; MatSetValues(C,1,&I,1,&J,&v,INSERT_VALUES);}
32: if (j>0) {J = I - 1; MatSetValues(C,1,&I,1,&J,&v,INSERT_VALUES);}
33: if (j<n-1) {J = I + 1; MatSetValues(C,1,&I,1,&J,&v,INSERT_VALUES);}
34: v = 4.0; MatSetValues(C,1,&I,1,&I,&v,INSERT_VALUES);
35: }
36: }
37: MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);
38: MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);
39: MatGetOrdering(C,MATORDERING_RCM,&perm,&iperm);
40: MatView(C,PETSC_VIEWER_STDOUT_WORLD);
41: ISView(perm,PETSC_VIEWER_STDOUT_SELF);
42: VecCreateSeq(PETSC_COMM_SELF,m*n,&u);
43: VecSet(&one,u);
44: VecDuplicate(u,&x);
45: VecDuplicate(u,&b);
46: VecDuplicate(u,&y);
47: MatMult(C,u,b);
48: VecCopy(b,y);
49: VecScale(&alpha,y);
51: MatNorm(C,NORM_FROBENIUS,&norm);
52: PetscPrintf(PETSC_COMM_SELF,"Frobenius norm of matrix %gn",norm);
53: MatNorm(C,NORM_1,&norm);
54: PetscPrintf(PETSC_COMM_SELF,"One norm of matrix %gn",norm);
55: MatNorm(C,NORM_INFINITY,&norm);
56: PetscPrintf(PETSC_COMM_SELF,"Infinity norm of matrix %gn",norm);
58: MatLUFactor(C,perm,iperm,PETSC_NULL);
59: MatView(C,PETSC_VIEWER_STDOUT_WORLD);
61: /* Test MatSolve */
62: MatSolve(C,b,x);
63: VecView(b,PETSC_VIEWER_STDOUT_SELF);
64: VecView(x,PETSC_VIEWER_STDOUT_SELF);
65: VecAXPY(&mone,u,x);
66: VecNorm(x,NORM_2,&norm);
67: PetscPrintf(PETSC_COMM_SELF,"Norm of error %An",norm);
69: /* Test MatSolveAdd */
70: MatSolveAdd(C,b,y,x);
72: VecAXPY(&mone,y,x);
73: VecAXPY(&mone,u,x);
74: VecNorm(x,NORM_2,&norm);
76: PetscPrintf(PETSC_COMM_SELF,"Norm of error %An",norm);
78: ISDestroy(perm);
79: ISDestroy(iperm);
80: VecDestroy(u);
81: VecDestroy(y);
82: VecDestroy(b);
83: VecDestroy(x);
84: MatDestroy(C);
85: PetscFinalize();
86: return 0;
87: }