xref: /petsc/src/mat/utils/convert.c (revision 395cb87ed7e646d29fa62472d8e7feeacac43fb4)
1 #ifndef lint
2 static char vcid[] = "$Id: convert.c,v 1.14 1995/05/05 15:57:56 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 #define  ABS(a) ((a > 0) ? a : -a)
10 
11 /* Determines the block diagonals within a subset of a matrix */
12 /* For now this is just sequential -- not parallel */
13 
14 /*
15    MatDetermineDiagonals_Private - Determines the diagonal structure
16    of a matrix.
17 
18    Input Parameters:
19 .  mat - the matrix
20 .  nb - block size
21 .  irows - rows to use
22 .  icols - columns to use
23 
24    Output Parameters:
25 .  ndiag - number of diagonals
26 .  diagonals - the diagonal numbers
27 
28    Note:  The user must free the diagonals array.
29  */
30 
31 int MatDetermineDiagonals_Private(Mat mat,int nb,int newr,int newc,
32             int *rowrange, int *colrange,int *ndiag, int **diagonals)
33 {
34   int    nd, clast, cfirst, ierr, nnc, maxd, nz, *col, *cwork, *diag;
35   int    i, j, k, jdiag, cshift, row, dnew, temp;
36   Scalar *v;
37 
38   VALIDHEADER(mat,MAT_COOKIE);
39   if ((newr%nb) || (newc%nb)) SETERR(1,"Invalid block size.");
40   cfirst = colrange[0];
41   clast  = colrange[newc-1];
42   nnc    = clast - cfirst + 1;
43   cwork  = (int *) MALLOC( nnc * sizeof(int) );	CHKPTR(cwork);
44   for (i=0; i<nnc; i++)  cwork[i] = -1;
45   for (i=0; i<newc; i++) cwork[colrange[i]-cfirst] = i;
46 
47   /* Determine which diagonals exist:  compute nd, diag[]: */
48   /* Temporarily ssume diag[0] = 0 (main diagonal) */
49   maxd = newr + newc - 1;	/* maximum possible diagonals */
50   diag = (int *)MALLOC( maxd * sizeof(int) );	CHKPTR(diag);
51   nd = 1;
52   for (i=0; i<maxd; i++) diag[i] = 0;
53   for (i=0; i<newr; i++) {
54     ierr = MatGetRow( mat, rowrange[i], &nz, &col, &v ); CHKERR(ierr);
55     row = i;
56     j   = 0;
57     /* Skip values until we reach the first column */
58     while (j < nz && col[j] < cfirst) j++;
59     while (j < nz) {
60       if (clast < col[j]) break;
61       cshift = cwork[col[j] - cfirst];
62       if (cshift >= 0) {
63         /* Determine if diagonal block already exits for valid colum */
64         dnew = 1;
65         jdiag = row/nb - cshift/nb;
66         for (k=0; k<nd; k++) {
67           if (diag[k] == jdiag) {	/* diagonal exists */
68             dnew = 0;	break;
69           }
70         }
71         if (dnew) {
72 	  diag[nd] = jdiag;
73 	  nd++;
74           if (ABS(jdiag) > newr/nb)
75              { printf("ERROR jdiag\n"); }
76         }
77       }
78       j++;
79     }
80     ierr = MatRestoreRow( mat, rowrange[i], &nz, &col, &v ); CHKERR(ierr);
81   }
82   /* Sort diagonals in decreasing order. */
83   for (k=0; k<nd; k++) {
84     for (j=k+1; j<nd; j++) {
85       if (diag[k] < diag[j]) {
86         temp = diag[k];
87         diag[k] = diag[j];
88         diag[j] = temp;
89       }
90     }
91   }
92   FREE( cwork );
93   *ndiag = nd;
94   *diagonals = diag;
95   return 0;
96 }
97 
98 /*
99   MatConvert_AIJ - Converts from MATAIJ format to another sequential format.
100  */
101 int MatConvert_AIJ(Mat mat, MatType newtype, Mat *newmat)
102 {
103   Mat_AIJ *aij = (Mat_AIJ *) mat->data;
104   Scalar  *vwork;
105   int     i, ierr, nz, m = aij->m, n = aij->n, *cwork;
106 
107   if (mat->type != MATAIJ) SETERR(1,"Input matrix must be MATAIJ.");
108   switch (newtype) {
109     case MATROW:
110       ierr = MatCreateSequentialRow(mat->comm,m,n,0,aij->ilen,newmat);
111       CHKERR(ierr); break;
112     case MATDENSE:
113       ierr = MatCreateSequentialDense(mat->comm,m,n,newmat);
114       CHKERR(ierr); break;
115     case MATBDIAG:
116     { int nb = 1; /* Default block size = 1 */
117       int ndiag, *diag, *rr, *cr;
118       rr = (int *) MALLOC( (m+n) * sizeof(int) ); CHKPTR(rr);
119       cr = rr + m;
120       for (i=0; i<m; i++) rr[i] = i;
121       for (i=0; i<n; i++) cr[i] = i;
122       OptionsGetInt(0,0,"-mat_bdiag_bsize",&nb);
123       ierr = MatDetermineDiagonals_Private(mat,nb,m,n,rr,cr,&ndiag,&diag);
124       ierr = MatCreateSequentialBDiag(mat->comm,m,n,ndiag,nb,diag,0,newmat);
125       FREE(rr), FREE(diag);
126       CHKERR(ierr); break;
127     }
128     default:
129       SETERR(1,"Only MATROW, MATDENSE, and MATBDIAG are currently supported.");
130   }
131   for (i=0; i<m; i++) {
132     ierr = MatGetRow(mat,i,&nz,&cwork,&vwork); CHKERR(ierr);
133     ierr = MatSetValues(*newmat,1,&i,nz,cwork,vwork,INSERTVALUES);
134            CHKERR(ierr);
135     ierr = MatRestoreRow(mat,i,&nz,&cwork,&vwork); CHKERR(ierr);
136   }
137   ierr = MatAssemblyBegin(*newmat,FINAL_ASSEMBLY); CHKERR(ierr);
138   ierr = MatAssemblyEnd(*newmat,FINAL_ASSEMBLY); CHKERR(ierr);
139   return 0;
140 }
141 /* ------------------------------------------------------------------ */
142 /*
143   MatConvert_MPIAIJ - Converts from MATMPIAIJ format to another
144   parallel format.
145  */
146 int MatConvert_MPIAIJ(Mat mat, MatType newtype, Mat *newmat)
147 {
148   Mat_MPIAIJ *aij = (Mat_MPIAIJ *) mat->data;
149   Mat_AIJ    *Ad = (Mat_AIJ *)(aij->A->data), *Bd = (Mat_AIJ *)(aij->B->data);
150   int        ierr, nz, i, ig,rstart = aij->rstart, m = aij->m, *cwork;
151   Scalar     *vwork;
152 
153   if (mat->type != MATMPIAIJ) SETERR(1,"Input matrix must be MATMPIAIJ.");
154   switch (newtype) {
155     case MATMPIROW:
156       for (i=0; i<m; i++)
157         {ierr = MatCreateMPIRow(mat->comm,m,aij->n,aij->M,aij->N,0,Ad->ilen,
158 			0,Bd->ilen,newmat); CHKERR(ierr); }
159       break;
160     default:
161       SETERR(1,"Only MATMPIROW is currently suported.");
162   }
163   /* Each processor converts its local rows */
164   for (i=0; i<m; i++) {
165     ig   = i + rstart;
166     ierr = MatGetRow(mat,ig,&nz,&cwork,&vwork);	CHKERR(ierr);
167     ierr = MatSetValues(*newmat,1,&ig,nz,cwork,vwork,
168 		INSERTVALUES); CHKERR(ierr);
169     ierr = MatRestoreRow(mat,ig,&nz,&cwork,&vwork); CHKERR(ierr);
170   }
171   ierr = MatAssemblyBegin(*newmat,FINAL_ASSEMBLY); CHKERR(ierr);
172   ierr = MatAssemblyEnd(*newmat,FINAL_ASSEMBLY); CHKERR(ierr);
173   return 0;
174 }
175