xref: /petsc/src/mat/tutorials/ex12.c (revision c4762a1b19cd2af06abeed90e8f9d34fb975dd94)
1*c4762a1bSJed Brown 
2*c4762a1bSJed Brown static char help[] = "Reads a PETSc matrix and vector from a file; expands the matrix with the vector\n\n";
3*c4762a1bSJed Brown 
4*c4762a1bSJed Brown /*T
5*c4762a1bSJed Brown    Concepts: Mat^ordering a matrix - loading a binary matrix and vector;
6*c4762a1bSJed Brown    Concepts: Mat^loading a binary matrix and vector;
7*c4762a1bSJed Brown    Concepts: Vectors^loading a binary vector;
8*c4762a1bSJed Brown    Concepts: PetscLog^preloading executable
9*c4762a1bSJed Brown    Processors: 1
10*c4762a1bSJed Brown T*/
11*c4762a1bSJed Brown 
12*c4762a1bSJed Brown 
13*c4762a1bSJed Brown 
14*c4762a1bSJed Brown /*
15*c4762a1bSJed Brown   Include "petscmat.h" so that we can use matrices.
16*c4762a1bSJed Brown   automatically includes:
17*c4762a1bSJed Brown      petscsys.h       - base PETSc routines   petscvec.h    - vectors
18*c4762a1bSJed Brown      petscmat.h    - matrices
19*c4762a1bSJed Brown      petscis.h     - index sets            petscviewer.h - viewers
20*c4762a1bSJed Brown */
21*c4762a1bSJed Brown #include <petscmat.h>
22*c4762a1bSJed Brown 
23*c4762a1bSJed Brown /*
24*c4762a1bSJed Brown 
25*c4762a1bSJed Brown    Adds a new column and row to the vector (the last) containing the vector
26*c4762a1bSJed Brown */
27*c4762a1bSJed Brown PetscErrorCode PadMatrix(Mat A,Vec v,PetscScalar c,Mat *B)
28*c4762a1bSJed Brown {
29*c4762a1bSJed Brown   PetscErrorCode    ierr;
30*c4762a1bSJed Brown   PetscInt          n,i,*cnt,*indices,nc;
31*c4762a1bSJed Brown   const PetscInt    *aj;
32*c4762a1bSJed Brown   const PetscScalar *vv,*aa;
33*c4762a1bSJed Brown 
34*c4762a1bSJed Brown   PetscFunctionBegin;
35*c4762a1bSJed Brown   ierr = MatGetSize(A,&n,NULL);CHKERRQ(ierr);
36*c4762a1bSJed Brown   ierr = VecGetArrayRead(v,&vv);CHKERRQ(ierr);
37*c4762a1bSJed Brown   ierr = PetscMalloc1(n,&indices);CHKERRQ(ierr);
38*c4762a1bSJed Brown   for (i=0; i<n; i++) indices[i] = i;
39*c4762a1bSJed Brown 
40*c4762a1bSJed Brown   /* determine number of nonzeros per row in the new matrix */
41*c4762a1bSJed Brown   ierr = PetscMalloc1(n+1,&cnt);CHKERRQ(ierr);
42*c4762a1bSJed Brown   for (i=0; i<n; i++) {
43*c4762a1bSJed Brown     ierr = MatGetRow(A,i,&nc,NULL,NULL);CHKERRQ(ierr);
44*c4762a1bSJed Brown     cnt[i] = nc + (vv[i] != 0.0);
45*c4762a1bSJed Brown     ierr = MatRestoreRow(A,i,&nc,NULL,NULL);CHKERRQ(ierr);
46*c4762a1bSJed Brown   }
47*c4762a1bSJed Brown   cnt[n] = 1;
48*c4762a1bSJed Brown   for (i=0; i<n; i++) {
49*c4762a1bSJed Brown     cnt[n] += (vv[i] != 0.0);
50*c4762a1bSJed Brown   }
51*c4762a1bSJed Brown   ierr = MatCreateSeqAIJ(PETSC_COMM_SELF,n+1,n+1,0,cnt,B);CHKERRQ(ierr);
52*c4762a1bSJed Brown   ierr = MatSetOption(*B,MAT_IGNORE_ZERO_ENTRIES,PETSC_TRUE);CHKERRQ(ierr);
53*c4762a1bSJed Brown 
54*c4762a1bSJed Brown   /* copy over the matrix entries from the matrix and then the vector */
55*c4762a1bSJed Brown   for (i=0; i<n; i++) {
56*c4762a1bSJed Brown     ierr = MatGetRow(A,i,&nc,&aj,&aa);CHKERRQ(ierr);
57*c4762a1bSJed Brown     ierr = MatSetValues(*B,1,&i,nc,aj,aa,INSERT_VALUES);CHKERRQ(ierr);
58*c4762a1bSJed Brown     ierr = MatRestoreRow(A,i,&nc,&aj,&aa);CHKERRQ(ierr);
59*c4762a1bSJed Brown   }
60*c4762a1bSJed Brown   ierr = MatSetValues(*B,1,&n,n,indices,vv,INSERT_VALUES);CHKERRQ(ierr);
61*c4762a1bSJed Brown   ierr = MatSetValues(*B,n,indices,1,&n,vv,INSERT_VALUES);CHKERRQ(ierr);
62*c4762a1bSJed Brown   ierr = MatSetValues(*B,1,&n,1,&n,&c,INSERT_VALUES);CHKERRQ(ierr);
63*c4762a1bSJed Brown 
64*c4762a1bSJed Brown   ierr = MatAssemblyBegin(*B,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
65*c4762a1bSJed Brown   ierr = MatAssemblyEnd(*B,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
66*c4762a1bSJed Brown   ierr = VecRestoreArrayRead(v,&vv);CHKERRQ(ierr);
67*c4762a1bSJed Brown   ierr = PetscFree(cnt);CHKERRQ(ierr);
68*c4762a1bSJed Brown   ierr = PetscFree(indices);CHKERRQ(ierr);
69*c4762a1bSJed Brown   PetscFunctionReturn(0);
70*c4762a1bSJed Brown }
71*c4762a1bSJed Brown 
72*c4762a1bSJed Brown 
73*c4762a1bSJed Brown int main(int argc,char **args)
74*c4762a1bSJed Brown {
75*c4762a1bSJed Brown   Mat            A,B;
76*c4762a1bSJed Brown   PetscViewer    fd;                        /* viewer */
77*c4762a1bSJed Brown   char           file[PETSC_MAX_PATH_LEN];  /* input file name */
78*c4762a1bSJed Brown   PetscErrorCode ierr;
79*c4762a1bSJed Brown   PetscBool      flg;
80*c4762a1bSJed Brown   Vec            v;
81*c4762a1bSJed Brown 
82*c4762a1bSJed Brown   ierr = PetscInitialize(&argc,&args,(char*)0,help);if (ierr) return ierr;
83*c4762a1bSJed Brown   /*
84*c4762a1bSJed Brown      Determine files from which we read the two linear systems
85*c4762a1bSJed Brown      (matrix and right-hand-side vector).
86*c4762a1bSJed Brown   */
87*c4762a1bSJed Brown   ierr = PetscOptionsGetString(NULL,NULL,"-f0",file,PETSC_MAX_PATH_LEN,&flg);CHKERRQ(ierr);
88*c4762a1bSJed Brown   if (!flg) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_USER,"Must indicate binary file with the -f0 option");
89*c4762a1bSJed Brown 
90*c4762a1bSJed Brown   ierr = PetscViewerBinaryOpen(PETSC_COMM_WORLD,file,FILE_MODE_READ,&fd);CHKERRQ(ierr);
91*c4762a1bSJed Brown 
92*c4762a1bSJed Brown   ierr = MatCreate(PETSC_COMM_WORLD,&A);CHKERRQ(ierr);
93*c4762a1bSJed Brown   ierr = MatSetType(A,MATSEQAIJ);CHKERRQ(ierr);
94*c4762a1bSJed Brown   ierr = MatLoad(A,fd);CHKERRQ(ierr);
95*c4762a1bSJed Brown   ierr = VecCreate(PETSC_COMM_WORLD,&v);CHKERRQ(ierr);
96*c4762a1bSJed Brown   ierr = VecLoad(v,fd);CHKERRQ(ierr);
97*c4762a1bSJed Brown   ierr = MatView(A,PETSC_VIEWER_STDOUT_SELF);CHKERRQ(ierr);
98*c4762a1bSJed Brown   ierr = PadMatrix(A,v,3.0,&B);CHKERRQ(ierr);
99*c4762a1bSJed Brown   ierr = MatView(B,PETSC_VIEWER_STDOUT_SELF);CHKERRQ(ierr);
100*c4762a1bSJed Brown   ierr = MatDestroy(&B);CHKERRQ(ierr);
101*c4762a1bSJed Brown   ierr = MatDestroy(&A);CHKERRQ(ierr);
102*c4762a1bSJed Brown   ierr = VecDestroy(&v);CHKERRQ(ierr);
103*c4762a1bSJed Brown   ierr = PetscViewerDestroy(&fd);CHKERRQ(ierr);
104*c4762a1bSJed Brown 
105*c4762a1bSJed Brown   ierr = PetscFinalize();
106*c4762a1bSJed Brown   return ierr;
107*c4762a1bSJed Brown }
108*c4762a1bSJed Brown 
109*c4762a1bSJed Brown 
110*c4762a1bSJed Brown 
111*c4762a1bSJed Brown /*TEST
112*c4762a1bSJed Brown 
113*c4762a1bSJed Brown    test:
114*c4762a1bSJed Brown       args: -f0 ${wPETSC_DIR}/share/petsc/datafiles/matrices/ns-real-int32-float64
115*c4762a1bSJed Brown       requires: double !complex !define(PETSC_USE_64BIT_INDICES)
116*c4762a1bSJed Brown 
117*c4762a1bSJed Brown TEST*/
118