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 PetscFunctionBeginUser; 15 PetscCall(PetscInitialize(&argc,&args,(char*)0,help)); 16 PetscCall(PetscOptionsGetReal(NULL,NULL,"-omega",&omega,NULL)); 17 PetscCall(PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL)); 18 19 PetscCall(MatCreate(PETSC_COMM_SELF,&C)); 20 PetscCall(MatSetSizes(C,n,n,n,n)); 21 PetscCall(MatSetType(C,MATSEQDENSE)); 22 PetscCall(MatSetUp(C)); 23 PetscCall(VecCreateSeq(PETSC_COMM_SELF,n,&b)); 24 PetscCall(VecCreateSeq(PETSC_COMM_SELF,n,&x)); 25 PetscCall(VecCreateSeq(PETSC_COMM_SELF,n,&u)); 26 PetscCall(VecCreateSeq(PETSC_COMM_SELF,n,&e)); 27 PetscCall(VecSet(u,1.0)); 28 PetscCall(VecSet(x,0.0)); 29 30 v[0] = -1.; v[1] = 2.; v[2] = -1.; 31 for (i=1; i<n-1; i++) { 32 midx[0] = i-1; midx[1] = i; midx[2] = i+1; 33 PetscCall(MatSetValues(C,1,&i,3,midx,v,INSERT_VALUES)); 34 } 35 i = 0; midx[0] = 0; midx[1] = 1; 36 v[0] = 2.0; v[1] = -1.; 37 PetscCall(MatSetValues(C,1,&i,2,midx,v,INSERT_VALUES)); 38 i = n-1; midx[0] = n-2; midx[1] = n-1; 39 v[0] = -1.0; v[1] = 2.; 40 PetscCall(MatSetValues(C,1,&i,2,midx,v,INSERT_VALUES)); 41 42 PetscCall(MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY)); 43 PetscCall(MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY)); 44 45 PetscCall(MatMult(C,u,b)); 46 47 for (i=0; i<n; i++) { 48 PetscCall(MatSOR(C,b,omega,SOR_FORWARD_SWEEP,0.0,1,1,x)); 49 PetscCall(VecWAXPY(e,-1.0,x,u)); 50 PetscCall(VecNorm(e,NORM_2,&norm)); 51 PetscCall(PetscPrintf(PETSC_COMM_SELF,"2-norm of error %g\n",(double)norm)); 52 } 53 PetscCall(MatDestroy(&C)); 54 PetscCall(VecDestroy(&x)); 55 PetscCall(VecDestroy(&b)); 56 PetscCall(VecDestroy(&u)); 57 PetscCall(VecDestroy(&e)); 58 PetscCall(PetscFinalize()); 59 return 0; 60 } 61 62 /*TEST 63 64 test: 65 66 TEST*/ 67