xref: /petsc/src/mat/utils/freespace.c (revision 0700a8246d308f50502909ba325e6169d3ee27eb)
1 #define PETSCMAT_DLL
2 
3 #include "../src/mat/utils/freespace.h"
4 
5 #undef __FUNCT__
6 #define __FUNCT__ "PetscFreeSpaceGet"
7 PetscErrorCode PetscFreeSpaceGet(PetscInt n,PetscFreeSpaceList *list)
8 {
9   PetscFreeSpaceList a;
10   PetscErrorCode     ierr;
11 
12   PetscFunctionBegin;
13   ierr = PetscMalloc(sizeof(struct _Space),&a);CHKERRQ(ierr);
14   ierr = PetscMalloc(n*sizeof(PetscInt),&(a->array_head));CHKERRQ(ierr);
15   a->array            = a->array_head;
16   a->local_remaining  = n;
17   a->local_used       = 0;
18   a->total_array_size = 0;
19   a->more_space       = NULL;
20 
21   if (*list) {
22     (*list)->more_space = a;
23     a->total_array_size = (*list)->total_array_size;
24   }
25 
26   a->total_array_size += n;
27   *list               =  a;
28   PetscFunctionReturn(0);
29 }
30 
31 #undef __FUNCT__
32 #define __FUNCT__ "PetscFreeSpaceContiguous"
33 PetscErrorCode PetscFreeSpaceContiguous(PetscFreeSpaceList *head,PetscInt *space)
34 {
35   PetscFreeSpaceList a;
36   PetscErrorCode     ierr;
37 
38   PetscFunctionBegin;
39   while ((*head)) {
40     a     =  (*head)->more_space;
41     ierr  =  PetscMemcpy(space,(*head)->array_head,((*head)->local_used)*sizeof(PetscInt));CHKERRQ(ierr);
42     space += (*head)->local_used;
43     ierr  =  PetscFree((*head)->array_head);CHKERRQ(ierr);
44     ierr  =  PetscFree(*head);CHKERRQ(ierr);
45     *head =  a;
46   }
47   PetscFunctionReturn(0);
48 }
49 
50 /*
51   PetscFreeSpaceContiguous_LU -
52     Copy a linket list obtained from matrix symbolic ILU or LU factorization into a contiguous array
53   that enables an efficient matrix triangular solve.
54 
55    Input Parameters:
56 +  head - linked list of column indices obtained from matrix symbolic ILU or LU factorization
57 .  space - an allocated int array with length nnz of factored matrix.
58 .  n - order of the matrix
59 .  bi - row pointer of factored matrix L with length n+1.
60 -  bdiag - int array of length n+1. bdiag[i] points to diagonal of U(i,:), and bdiag[n] points to entry of U(n-1,0)-1.
61 
62    Output Parameter:
63 .  space - column indices are copied into this int array with contiguous layout of L and U
64 
65    See MatILUFactorSymbolic_SeqAIJ_ilu0() for detailed data structure of L and U
66 */
67 #undef __FUNCT__
68 #define __FUNCT__ "PetscFreeSpaceContiguous_LU"
69 PetscErrorCode PetscFreeSpaceContiguous_LU(PetscFreeSpaceList *head,PetscInt *space,PetscInt n,PetscInt *bi,PetscInt *bdiag)
70 {
71   PetscFreeSpaceList a;
72   PetscErrorCode     ierr;
73   PetscInt           row,nnz,*bj,*array,total,bi_temp;
74   PetscInt           nnzL,nnzU;
75 
76   PetscFunctionBegin;
77   bi_temp = bi[n];
78   row       = 0;
79   total     = 0;
80   nnzL  = bdiag[0];
81   while ((*head)!=NULL) {
82     total += (*head)->local_used;
83     array  = (*head)->array_head;
84 
85     while (row < n) {
86       if (bi[row+1] > total) break;
87       /* copy array entries into bj for this row */
88       nnz  = bi[row+1] - bi[row];
89       /* set bi[row] for new datastruct */
90       if (row == 0 ){
91         bi[row] = 0;
92       } else {
93         bi[row] = bi[row-1] + nnzL; /* nnzL of previous row */
94       }
95 
96       /* L part */
97       nnzL = bdiag[row];
98       bj   = space+bi[row];
99       ierr = PetscMemcpy(bj,array,nnzL*sizeof(PetscInt));CHKERRQ(ierr);
100 
101       /* diagonal entry */
102       bdiag[row] = bi_temp - 1;
103       space[bdiag[row]] = row;
104 
105       /* U part */
106       nnzU        = nnz - nnzL;
107       bi_temp = bi_temp - nnzU;
108       nnzU --;      /* exclude diagonal */
109       bj = space + bi_temp;
110       ierr = PetscMemcpy(bj,array+nnzL+1,nnzU*sizeof(PetscInt));CHKERRQ(ierr);
111       array += nnz;
112       row++;
113     }
114 
115     a     = (*head)->more_space;
116     ierr  = PetscFree((*head)->array_head);CHKERRQ(ierr);
117     ierr  = PetscFree(*head);CHKERRQ(ierr);
118     *head = a;
119   }
120   bi[n] = bi[n-1] + nnzL;
121   bdiag[n] = bdiag[n-1]-1;
122   PetscFunctionReturn(0);
123 }
124 
125 /*
126   PetscFreeSpaceContiguous_Cholesky -
127     Copy a linket list obtained from matrix symbolic ICC or Cholesky factorization into a contiguous array
128   that enables an efficient matrix triangular solve.
129 
130    Input Parameters:
131 +  head - linked list of column indices obtained from matrix symbolic ICC or Cholesky factorization
132 .  space - an allocated int array with length nnz of factored matrix.
133 .  n - order of the matrix
134 .  ui - row pointer of factored matrix with length n+1. All entries are set based on the traditional layout U matrix.
135 -  udiag - int array of length n.
136 
137    Output Parameter:
138 +  space - column indices are copied into this int array with contiguous layout of U, with diagonal located as the last entry in each row
139 -  udiag - indices of diagonal entries
140 
141    See MatICCFactorSymbolic_SeqAIJ_newdatastruct() for detailed description.
142 */
143 
144 #undef __FUNCT__
145 #define __FUNCT__ "PetscFreeSpaceContiguous_Cholesky"
146 PetscErrorCode PetscFreeSpaceContiguous_Cholesky(PetscFreeSpaceList *head,PetscInt *space,PetscInt n,PetscInt *ui,PetscInt *udiag)
147 {
148   PetscFreeSpaceList a;
149   PetscErrorCode     ierr;
150   PetscInt           row,nnz,*uj,*array,total;
151 
152   PetscFunctionBegin;
153   row   = 0;
154   total = 0;
155   while (*head) {
156     total += (*head)->local_used;
157     array  = (*head)->array_head;
158 
159     while (row < n){
160       if (ui[row+1] > total) break;
161       udiag[row] = ui[row+1] - 1;     /* points to the last entry of U(row,:) */
162       nnz  = ui[row+1] - ui[row] - 1; /* exclude diagonal */
163       uj   = space + ui[row];
164       ierr = PetscMemcpy(uj,array+1,nnz*sizeof(PetscInt));CHKERRQ(ierr);
165       uj[nnz] = array[0]; /* diagonal */
166       array += nnz + 1;
167       row++;
168     }
169 
170     a     = (*head)->more_space;
171     ierr  = PetscFree((*head)->array_head);CHKERRQ(ierr);
172     ierr  = PetscFree(*head);CHKERRQ(ierr);
173     *head = a;
174   }
175   PetscFunctionReturn(0);
176 }
177 
178 #undef __FUNCT__
179 #define __FUNCT__ "PetscFreeSpaceDestroy"
180 PetscErrorCode PetscFreeSpaceDestroy(PetscFreeSpaceList head)
181 {
182   PetscFreeSpaceList a;
183   PetscErrorCode     ierr;
184 
185   PetscFunctionBegin;
186   while ((head)!=NULL) {
187     a    = (head)->more_space;
188     ierr = PetscFree((head)->array_head);CHKERRQ(ierr);
189     ierr = PetscFree(head);CHKERRQ(ierr);
190     head = a;
191   }
192   PetscFunctionReturn(0);
193 }
194