Actual source code: ex3.c
1: /*$Id: ex3.c,v 1.19 2001/08/07 21:30:08 bsmith Exp $*/
3: static char help[] = "Tests relaxation for dense matrices.nn";
5: #include petscmat.h
7: int main(int argc,char **args)
8: {
9: Mat C;
10: Vec u,x,b,e;
11: int i,n = 10,midx[3],ierr;
12: PetscScalar v[3],one = 1.0,zero = 0.0,mone = -1.0;
13: PetscReal omega = 1.0,norm;
15: PetscInitialize(&argc,&args,(char *)0,help);
16: PetscOptionsGetReal(PETSC_NULL,"-omega",&omega,PETSC_NULL);
17: PetscOptionsGetInt(PETSC_NULL,"-n",&n,PETSC_NULL);
19: MatCreate(PETSC_COMM_SELF,n,n,n,n,&C);
20: MatSetType(C,MATSEQDENSE);
21: VecCreateSeq(PETSC_COMM_SELF,n,&b);
22: VecCreateSeq(PETSC_COMM_SELF,n,&x);
23: VecCreateSeq(PETSC_COMM_SELF,n,&u);
24: VecCreateSeq(PETSC_COMM_SELF,n,&e);
25: VecSet(&one,u);
26: VecSet(&zero,x);
28: v[0] = -1.; v[1] = 2.; v[2] = -1.;
29: for (i=1; i<n-1; i++){
30: midx[0] = i-1; midx[1] = i; midx[2] = i+1;
31: MatSetValues(C,1,&i,3,midx,v,INSERT_VALUES);
32: }
33: i = 0; midx[0] = 0; midx[1] = 1;
34: v[0] = 2.0; v[1] = -1.;
35: MatSetValues(C,1,&i,2,midx,v,INSERT_VALUES);
36: i = n-1; midx[0] = n-2; midx[1] = n-1;
37: v[0] = -1.0; v[1] = 2.;
38: MatSetValues(C,1,&i,2,midx,v,INSERT_VALUES);
40: MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);
41: MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);
43: MatMult(C,u,b);
45: for (i=0; i<n; i++) {
46: MatRelax(C,b,omega,SOR_FORWARD_SWEEP,0.0,1,1,x);
47: VecWAXPY(&mone,x,u,e);
48: VecNorm(e,NORM_2,&norm);
49: PetscPrintf(PETSC_COMM_SELF,"2-norm of error %gn",norm);
50: }
51: MatDestroy(C);
52: VecDestroy(x);
53: VecDestroy(b);
54: VecDestroy(u);
55: VecDestroy(e);
56: PetscFinalize();
57: return 0;
58: }
60: