Actual source code: ex78.c
petsc-3.6.4 2016-04-12
2: static char help[] = "Reads in a matrix in ASCII MATLAB format (I,J,A), read in vectors rhs and exact_solu in ASCII format.\n\
3: Writes them using the PETSc sparse format.\n\
4: Note: I and J start at 1, not 0, use -noshift if indices in file start with zero!\n\
5: Input parameters are:\n\
6: -Ain <filename> : input matrix in ascii format\n\
7: -rhs <filename> : input rhs in ascii format\n\
8: -solu <filename> : input true solution in ascii format\n\\n";
10: /*
11: Example: ./ex78 -Ain Ain -rhs rhs -solu solu -noshift -mat_view
12: with the datafiles in the followig format:
13: Ain (I and J start at 0):
14: ------------------------
15: 3 3 6
16: 0 0 1.0
17: 0 1 2.0
18: 1 0 3.0
19: 1 1 4.0
20: 1 2 5.0
21: 2 2 6.0
23: rhs
24: ---
25: 0 3.0
26: 1 12.0
27: 2 6.0
29: solu
30: ----
31: 0 1.0
32: 0 1.0
33: 0 1.0
34: */
36: #include <petscmat.h>
40: int main(int argc,char **args)
41: {
42: Mat A;
43: Vec b,u,u_tmp;
44: char Ain[PETSC_MAX_PATH_LEN],rhs[PETSC_MAX_PATH_LEN],solu[PETSC_MAX_PATH_LEN];
46: int m,n,nz,dummy; /* these are fscaned so kept as int */
47: PetscInt i,col,row,shift = 1,sizes[3],nsizes;
48: PetscScalar val;
49: PetscReal res_norm;
50: FILE *Afile,*bfile,*ufile;
51: PetscViewer view;
52: PetscBool flg_A,flg_b,flg_u,flg;
53: PetscMPIInt size;
55: PetscInitialize(&argc,&args,(char*)0,help);
56: MPI_Comm_size(PETSC_COMM_WORLD,&size);
57: if (size != 1) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_SUP,"This is a uniprocessor example only!");
59: /* Read in matrix, rhs and exact solution from ascii files */
60: PetscOptionsGetString(NULL,"-Ain",Ain,PETSC_MAX_PATH_LEN,&flg_A);
61: PetscOptionsHasName(NULL,"-noshift",&flg);
62: if (flg) shift = 0;
63: if (flg_A) {
64: PetscPrintf(PETSC_COMM_SELF,"\n Read matrix in ascii format ...\n");
65: PetscFOpen(PETSC_COMM_SELF,Ain,"r",&Afile);
66: nsizes = 3;
67: PetscOptionsGetIntArray(NULL,"-nosizesinfile",sizes,&nsizes,&flg);
68: if (flg) {
69: if (nsizes != 3) SETERRQ(PETSC_COMM_WORLD,1,"Must pass in three m,n,nz as arguments for -nosizesinfile");
70: m = sizes[0];
71: n = sizes[1];
72: nz = sizes[2];
73: } else {
74: fscanf(Afile,"%d %d %d\n",&m,&n,&nz);
75: }
76: PetscPrintf(PETSC_COMM_SELF,"m: %d, n: %d, nz: %d \n", m,n,nz);
77: if (m != n) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ, "Number of rows, cols must be same for this example\n");
78: MatCreate(PETSC_COMM_SELF,&A);
79: MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,m,n);
80: MatSetFromOptions(A);
81: MatSeqAIJSetPreallocation(A,nz/m,NULL);
82: MatSetOption(A,MAT_NEW_NONZERO_ALLOCATION_ERR,PETSC_FALSE);
84: for (i=0; i<nz; i++) {
85: fscanf(Afile,"%d %d %le\n",&row,&col,(double*)&val);
86: row -= shift; col -= shift; /* set index set starts at 0 */
87: MatSetValues(A,1,&row,1,&col,&val,INSERT_VALUES);
88: }
89: MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
90: MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
91: fflush(stdout);
92: fclose(Afile);
93: }
95: PetscOptionsGetString(NULL,"-rhs",rhs,PETSC_MAX_PATH_LEN,&flg_b);
96: if (flg_b) {
97: VecCreate(PETSC_COMM_SELF,&b);
98: VecSetSizes(b,PETSC_DECIDE,n);
99: VecSetFromOptions(b);
100: PetscPrintf(PETSC_COMM_SELF,"\n Read rhs in ascii format ...\n");
101: PetscFOpen(PETSC_COMM_SELF,rhs,"r",&bfile);
102: for (i=0; i<n; i++) {
103: fscanf(bfile,"%d %le\n",&dummy,(double*)&val);
104: VecSetValues(b,1,&i,&val,INSERT_VALUES);
105: }
106: VecAssemblyBegin(b);
107: VecAssemblyEnd(b);
108: fflush(stdout);
109: fclose(bfile);
110: }
112: PetscOptionsGetString(NULL,"-solu",solu,PETSC_MAX_PATH_LEN,&flg_u);
113: if (flg_u) {
114: VecCreate(PETSC_COMM_SELF,&u);
115: VecSetSizes(u,PETSC_DECIDE,n);
116: VecSetFromOptions(u);
117: PetscPrintf(PETSC_COMM_SELF,"\n Read exact solution in ascii format ...\n");
118: PetscFOpen(PETSC_COMM_SELF,solu,"r",&ufile);
119: for (i=0; i<n; i++) {
120: fscanf(ufile,"%d %le\n",&dummy,(double*)&val);
121: VecSetValues(u,1,&i,&val,INSERT_VALUES);
122: }
123: VecAssemblyBegin(u);
124: VecAssemblyEnd(u);
125: fflush(stdout);
126: fclose(ufile);
127: }
129: /* Write matrix, rhs and exact solution in Petsc binary file */
130: PetscPrintf(PETSC_COMM_SELF,"\n Write matrix in binary to 'matrix.dat' ...\n");
131: PetscViewerBinaryOpen(PETSC_COMM_SELF,"matrix.dat",FILE_MODE_WRITE,&view);
132: MatView(A,view);
134: if (flg_b) { /* Write rhs in Petsc binary file */
135: PetscPrintf(PETSC_COMM_SELF,"\n Write rhs in binary to 'matrix.dat' ...\n");
136: VecView(b,view);
137: }
138: if (flg_u) {
139: PetscPrintf(PETSC_COMM_SELF,"\n Write exact solution in binary to 'matrix.dat' ...\n");
140: VecView(u,view);
141: }
143: /* Check accuracy of the data */
144: if (flg_A & flg_b & flg_u) {
145: VecDuplicate(u,&u_tmp);
146: MatMult(A,u,u_tmp);
147: VecAXPY(u_tmp,-1.0,b);
148: VecNorm(u_tmp,NORM_2,&res_norm);
149: PetscPrintf(PETSC_COMM_SELF,"\n Accuracy of the reading data: | b - A*u |_2 : %g \n",res_norm);
150: VecDestroy(&u_tmp);
151: }
153: MatDestroy(&A);
154: if (flg_b) {VecDestroy(&b);}
155: if (flg_u) {VecDestroy(&u);}
156: PetscViewerDestroy(&view);
157: PetscFinalize();
158: return 0;
159: }