xref: /petsc/src/mat/tests/ex17.c (revision c4762a1b19cd2af06abeed90e8f9d34fb975dd94)
1*c4762a1bSJed Brown 
2*c4762a1bSJed Brown static char help[] = "Tests the use of MatSolveTranspose().\n\n";
3*c4762a1bSJed Brown 
4*c4762a1bSJed Brown #include <petscmat.h>
5*c4762a1bSJed Brown 
6*c4762a1bSJed Brown int main(int argc,char **args)
7*c4762a1bSJed Brown {
8*c4762a1bSJed Brown   Mat            C,A;
9*c4762a1bSJed Brown   PetscInt       i,j,m = 5,n = 5,Ii,J;
10*c4762a1bSJed Brown   PetscErrorCode ierr;
11*c4762a1bSJed Brown   PetscScalar    v,five = 5.0,one = 1.0;
12*c4762a1bSJed Brown   IS             isrow,row,col;
13*c4762a1bSJed Brown   Vec            x,u,b;
14*c4762a1bSJed Brown   PetscReal      norm;
15*c4762a1bSJed Brown   MatFactorInfo  info;
16*c4762a1bSJed Brown 
17*c4762a1bSJed Brown   ierr = PetscInitialize(&argc,&args,(char*)0,help);if (ierr) return ierr;
18*c4762a1bSJed Brown   ierr = PetscOptionsGetInt(NULL,NULL,"-m",&m,NULL);CHKERRQ(ierr);
19*c4762a1bSJed Brown   ierr = PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);CHKERRQ(ierr);
20*c4762a1bSJed Brown 
21*c4762a1bSJed Brown   ierr = MatCreateSeqAIJ(PETSC_COMM_SELF,m*n,m*n,5,NULL,&C);CHKERRQ(ierr);
22*c4762a1bSJed Brown   ierr = MatSetUp(C);CHKERRQ(ierr);
23*c4762a1bSJed Brown 
24*c4762a1bSJed Brown   /* create the matrix for the five point stencil, YET AGAIN*/
25*c4762a1bSJed Brown   for (i=0; i<m; i++) {
26*c4762a1bSJed Brown     for (j=0; j<n; j++) {
27*c4762a1bSJed Brown       v = -1.0;  Ii = j + n*i;
28*c4762a1bSJed Brown       if (i>0)   {J = Ii - n; ierr = MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);CHKERRQ(ierr);}
29*c4762a1bSJed Brown       if (i<m-1) {J = Ii + n; ierr = MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);CHKERRQ(ierr);}
30*c4762a1bSJed Brown       if (j>0)   {J = Ii - 1; ierr = MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);CHKERRQ(ierr);}
31*c4762a1bSJed Brown       if (j<n-1) {J = Ii + 1; ierr = MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);CHKERRQ(ierr);}
32*c4762a1bSJed Brown       v = 4.0; ierr = MatSetValues(C,1,&Ii,1,&Ii,&v,INSERT_VALUES);CHKERRQ(ierr);
33*c4762a1bSJed Brown     }
34*c4762a1bSJed Brown   }
35*c4762a1bSJed Brown   ierr = MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
36*c4762a1bSJed Brown   ierr = MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
37*c4762a1bSJed Brown 
38*c4762a1bSJed Brown   ierr = ISCreateStride(PETSC_COMM_SELF,(m*n)/2,0,2,&isrow);CHKERRQ(ierr);
39*c4762a1bSJed Brown   ierr = MatZeroRowsIS(C,isrow,five,0,0);CHKERRQ(ierr);
40*c4762a1bSJed Brown 
41*c4762a1bSJed Brown   ierr = VecCreateSeq(PETSC_COMM_SELF,m*n,&u);CHKERRQ(ierr);
42*c4762a1bSJed Brown   ierr = VecDuplicate(u,&x);CHKERRQ(ierr);
43*c4762a1bSJed Brown   ierr = VecDuplicate(u,&b);CHKERRQ(ierr);
44*c4762a1bSJed Brown   ierr = VecSet(u,one);CHKERRQ(ierr);
45*c4762a1bSJed Brown 
46*c4762a1bSJed Brown   ierr = MatMultTranspose(C,u,b);CHKERRQ(ierr);
47*c4762a1bSJed Brown 
48*c4762a1bSJed Brown   /* Set default ordering to be Quotient Minimum Degree; also read
49*c4762a1bSJed Brown      orderings from the options database */
50*c4762a1bSJed Brown   ierr = MatGetOrdering(C,MATORDERINGQMD,&row,&col);CHKERRQ(ierr);
51*c4762a1bSJed Brown 
52*c4762a1bSJed Brown   ierr = MatFactorInfoInitialize(&info);CHKERRQ(ierr);
53*c4762a1bSJed Brown   ierr = MatGetFactor(C,MATSOLVERPETSC,MAT_FACTOR_LU,&A);CHKERRQ(ierr);
54*c4762a1bSJed Brown   ierr = MatLUFactorSymbolic(A,C,row,col,&info);CHKERRQ(ierr);
55*c4762a1bSJed Brown   ierr = MatLUFactorNumeric(A,C,&info);CHKERRQ(ierr);
56*c4762a1bSJed Brown   ierr = MatSolveTranspose(A,b,x);CHKERRQ(ierr);
57*c4762a1bSJed Brown 
58*c4762a1bSJed Brown   ierr = ISView(row,PETSC_VIEWER_STDOUT_SELF);CHKERRQ(ierr);
59*c4762a1bSJed Brown   ierr = VecAXPY(x,-1.0,u);CHKERRQ(ierr);
60*c4762a1bSJed Brown   ierr = VecNorm(x,NORM_2,&norm);CHKERRQ(ierr);
61*c4762a1bSJed Brown   ierr = PetscPrintf(PETSC_COMM_SELF,"Norm of error %g\n",(double)norm);CHKERRQ(ierr);
62*c4762a1bSJed Brown 
63*c4762a1bSJed Brown   ierr = ISDestroy(&row);CHKERRQ(ierr);
64*c4762a1bSJed Brown   ierr = ISDestroy(&col);CHKERRQ(ierr);
65*c4762a1bSJed Brown   ierr = ISDestroy(&isrow);CHKERRQ(ierr);
66*c4762a1bSJed Brown   ierr = VecDestroy(&u);CHKERRQ(ierr);
67*c4762a1bSJed Brown   ierr = VecDestroy(&x);CHKERRQ(ierr);
68*c4762a1bSJed Brown   ierr = VecDestroy(&b);CHKERRQ(ierr);
69*c4762a1bSJed Brown   ierr = MatDestroy(&C);CHKERRQ(ierr);
70*c4762a1bSJed Brown   ierr = MatDestroy(&A);CHKERRQ(ierr);
71*c4762a1bSJed Brown   ierr = PetscFinalize();
72*c4762a1bSJed Brown   return ierr;
73*c4762a1bSJed Brown }
74*c4762a1bSJed Brown 
75*c4762a1bSJed Brown 
76*c4762a1bSJed Brown /*TEST
77*c4762a1bSJed Brown 
78*c4762a1bSJed Brown    test:
79*c4762a1bSJed Brown 
80*c4762a1bSJed Brown TEST*/
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