xref: /petsc/src/mat/utils/convert.c (revision c847780015836c3a3689ee87308fbd546a3e32be)
1 #ifndef lint
2 static char vcid[] = "$Id: convert.c,v 1.12 1995/05/03 01:02:02 curfman Exp bsmith $";
3 #endif
4 
5 /* Matrix conversion routines.  For now, this supports only AIJ */
6 
7 #include "mpiaij.h"
8 #include "options.h"
9 
10 /* Determines the block diagonals within a subset of a matrix */
11 /* For now this is just sequential -- not parallel */
12 
13 /*
14    MatDetermineDiagonals_Private - Determines the diagonal structure
15    of a matrix.
16 
17    Input Parameters:
18 .  mat - the matrix
19 .  nb - block size
20 .  irows - rows to use
21 .  icols - columns to use
22 
23    Output Parameters:
24 .  ndiag - number of diagonals
25 .  diagonals - the diagonal numbers
26 
27    Note:  The user must free the diagonals array.
28  */
29 
30 int MatDetermineDiagonals_Private(Mat mat,int nb,int newr,int newc,
31             int *rowrange, int *colrange,int *ndiag, int **diagonals)
32 {
33   int    nd, clast, cfirst, ierr, nnc, maxd, nz, *col, *cwork, *diag;
34   int    i, j, k, jdiag, cshift, row, dnew, temp;
35   Scalar *v;
36 
37   VALIDHEADER(mat,MAT_COOKIE);
38   if ((newr%nb) || (newc%nb)) SETERR(1,"Invalid block size.");
39   cfirst = colrange[0];
40   clast  = colrange[newc-1];
41   nnc    = clast - cfirst + 1;
42   cwork  = (int *) MALLOC( nnc * sizeof(int) );	CHKPTR(cwork);
43   for (i=0; i<nnc; i++)  cwork[i] = -1;
44   for (i=0; i<newc; i++) cwork[colrange[i]-cfirst] = i;
45 
46   /* Determine which diagonals exist:  compute nd, diag[]: */
47   /* Temporarily ssume diag[0] = 0 (main diagonal) */
48   maxd = newr + newc - 1;	/* maximum possible diagonals */
49   diag = (int *)MALLOC( maxd * sizeof(int) );	CHKPTR(diag);
50   nd = 1;
51   for (i=0; i<maxd; i++) diag[i] = 0;
52   for (i=0; i<newr; i++) {
53     ierr = MatGetRow( mat, rowrange[i], &nz, &col, &v ); CHKERR(ierr);
54     row = i;
55     j   = 0;
56     /* Skip values until we reach the first column */
57     while (j < nz && col[j] < cfirst) j++;
58     while (j < nz) {
59       if (clast < col[j]) break;
60       cshift = cwork[col[j] - cfirst];
61       if (cshift >= 0) {
62         /* Determine if diagonal block already exits for valid colum */
63         dnew = 1;
64         jdiag = row/nb - cshift/nb;
65         for (k=0; k<nd; k++) {
66           if (diag[k] == jdiag) {	/* diagonal exists */
67             dnew = 0;	break;
68           }
69         }
70         if (dnew) {
71 	  diag[nd] = jdiag;
72 	  nd++;
73           if (abs(jdiag) > newr/nb)
74              { printf("ERROR jdiag\n"); }
75         }
76       }
77       j++;
78     }
79     ierr = MatRestoreRow( mat, rowrange[i], &nz, &col, &v ); CHKERR(ierr);
80   }
81   /* Sort diagonals in decreasing order. */
82   for (k=0; k<nd; k++) {
83     for (j=k+1; j<nd; j++) {
84       if (diag[k] < diag[j]) {
85         temp = diag[k];
86         diag[k] = diag[j];
87         diag[j] = temp;
88       }
89     }
90   }
91   FREE( cwork );
92   *ndiag = nd;
93   *diagonals = diag;
94   return 0;
95 }
96 
97 /*
98   MatConvert_AIJ - Converts from MATAIJ format to another sequential format.
99  */
100 int MatConvert_AIJ(Mat mat, MatType newtype, Mat *newmat)
101 {
102   Mat_AIJ *aij = (Mat_AIJ *) mat->data;
103   Scalar  *vwork;
104   int     i, ierr, nz, m = aij->m, n = aij->n, *cwork;
105 
106   if (mat->type != MATAIJ) SETERR(1,"Input matrix must be MATAIJ.");
107   switch (newtype) {
108     case MATROW:
109       ierr = MatCreateSequentialRow(mat->comm,m,n,0,aij->ilen,newmat);
110       CHKERR(ierr); break;
111     case MATDENSE:
112       ierr = MatCreateSequentialDense(mat->comm,m,n,newmat);
113       CHKERR(ierr); break;
114     case MATBDIAG:
115     { int nb = 1; /* Default block size = 1 */
116       int ndiag, *diag, *rr, *cr;
117       rr = (int *) MALLOC( (m+n) * sizeof(int) ); CHKPTR(rr);
118       cr = rr + m;
119       for (i=0; i<m; i++) rr[i] = i;
120       for (i=0; i<n; i++) cr[i] = i;
121       OptionsGetInt(0,0,"-mat_bdiag_bsize",&nb);
122       ierr = MatDetermineDiagonals_Private(mat,nb,m,n,rr,cr,&ndiag,&diag);
123       ierr = MatCreateSequentialBDiag(mat->comm,m,n,ndiag,nb,diag,0,newmat);
124 
125       MatAssemblyEnd(*newmat,FINAL_ASSEMBLY); MatView(*newmat,0);
126 
127       FREE(rr), FREE(diag);
128       CHKERR(ierr); break;
129     }
130     default:
131       SETERR(1,"Only MATROW, MATDENSE, and MATBDIAG are currently supported.");
132   }
133   for (i=0; i<m; i++) {
134     ierr = MatGetRow(mat,i,&nz,&cwork,&vwork); CHKERR(ierr);
135     ierr = MatSetValues(*newmat,1,&i,nz,cwork,vwork,INSERTVALUES);
136            CHKERR(ierr);
137     ierr = MatRestoreRow(mat,i,&nz,&cwork,&vwork); CHKERR(ierr);
138   }
139   ierr = MatAssemblyBegin(*newmat,FINAL_ASSEMBLY); CHKERR(ierr);
140   ierr = MatAssemblyEnd(*newmat,FINAL_ASSEMBLY); CHKERR(ierr);
141   return 0;
142 }
143 /* ------------------------------------------------------------------ */
144 /*
145   MatConvert_MPIAIJ - Converts from MATMPIAIJ format to another
146   parallel format.
147  */
148 int MatConvert_MPIAIJ(Mat mat, MatType newtype, Mat *newmat)
149 {
150   Mat_MPIAIJ *aij = (Mat_MPIAIJ *) mat->data;
151   Mat_AIJ    *Ad = (Mat_AIJ *)(aij->A->data), *Bd = (Mat_AIJ *)(aij->B->data);
152   int        ierr, nz, i, ig,rstart = aij->rstart, m = aij->m, *cwork;
153   Scalar     *vwork;
154 
155   if (mat->type != MATMPIAIJ) SETERR(1,"Input matrix must be MATMPIAIJ.");
156   switch (newtype) {
157     case MATMPIROW:
158       for (i=0; i<m; i++)
159         {ierr = MatCreateMPIRow(mat->comm,m,aij->n,aij->M,aij->N,0,Ad->ilen,
160 			0,Bd->ilen,newmat); CHKERR(ierr); }
161       break;
162     default:
163       SETERR(1,"Only MATMPIROW is currently suported.");
164   }
165   /* Each processor converts its local rows */
166   for (i=0; i<m; i++) {
167     ig   = i + rstart;
168     ierr = MatGetRow(mat,ig,&nz,&cwork,&vwork);	CHKERR(ierr);
169     ierr = MatSetValues(*newmat,1,&ig,nz,cwork,vwork,
170 		INSERTVALUES); CHKERR(ierr);
171     ierr = MatRestoreRow(mat,ig,&nz,&cwork,&vwork); CHKERR(ierr);
172   }
173   ierr = MatAssemblyBegin(*newmat,FINAL_ASSEMBLY); CHKERR(ierr);
174   ierr = MatAssemblyEnd(*newmat,FINAL_ASSEMBLY); CHKERR(ierr);
175   return 0;
176 }
177