1 2 static char help[] = "Tests relaxation for dense matrices.\n\n"; 3 4 #include <petscmat.h> 5 6 int main(int argc,char **args) 7 { 8 Mat C; 9 Vec u,x,b,e; 10 PetscInt i,n = 10,midx[3]; 11 PetscScalar v[3]; 12 PetscReal omega = 1.0,norm; 13 14 CHKERRQ(PetscInitialize(&argc,&args,(char*)0,help)); 15 CHKERRQ(PetscOptionsGetReal(NULL,NULL,"-omega",&omega,NULL)); 16 CHKERRQ(PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL)); 17 18 CHKERRQ(MatCreate(PETSC_COMM_SELF,&C)); 19 CHKERRQ(MatSetSizes(C,n,n,n,n)); 20 CHKERRQ(MatSetType(C,MATSEQDENSE)); 21 CHKERRQ(MatSetUp(C)); 22 CHKERRQ(VecCreateSeq(PETSC_COMM_SELF,n,&b)); 23 CHKERRQ(VecCreateSeq(PETSC_COMM_SELF,n,&x)); 24 CHKERRQ(VecCreateSeq(PETSC_COMM_SELF,n,&u)); 25 CHKERRQ(VecCreateSeq(PETSC_COMM_SELF,n,&e)); 26 CHKERRQ(VecSet(u,1.0)); 27 CHKERRQ(VecSet(x,0.0)); 28 29 v[0] = -1.; v[1] = 2.; v[2] = -1.; 30 for (i=1; i<n-1; i++) { 31 midx[0] = i-1; midx[1] = i; midx[2] = i+1; 32 CHKERRQ(MatSetValues(C,1,&i,3,midx,v,INSERT_VALUES)); 33 } 34 i = 0; midx[0] = 0; midx[1] = 1; 35 v[0] = 2.0; v[1] = -1.; 36 CHKERRQ(MatSetValues(C,1,&i,2,midx,v,INSERT_VALUES)); 37 i = n-1; midx[0] = n-2; midx[1] = n-1; 38 v[0] = -1.0; v[1] = 2.; 39 CHKERRQ(MatSetValues(C,1,&i,2,midx,v,INSERT_VALUES)); 40 41 CHKERRQ(MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY)); 42 CHKERRQ(MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY)); 43 44 CHKERRQ(MatMult(C,u,b)); 45 46 for (i=0; i<n; i++) { 47 CHKERRQ(MatSOR(C,b,omega,SOR_FORWARD_SWEEP,0.0,1,1,x)); 48 CHKERRQ(VecWAXPY(e,-1.0,x,u)); 49 CHKERRQ(VecNorm(e,NORM_2,&norm)); 50 CHKERRQ(PetscPrintf(PETSC_COMM_SELF,"2-norm of error %g\n",(double)norm)); 51 } 52 CHKERRQ(MatDestroy(&C)); 53 CHKERRQ(VecDestroy(&x)); 54 CHKERRQ(VecDestroy(&b)); 55 CHKERRQ(VecDestroy(&u)); 56 CHKERRQ(VecDestroy(&e)); 57 CHKERRQ(PetscFinalize()); 58 return 0; 59 } 60 61 /*TEST 62 63 test: 64 65 TEST*/ 66