xref: /petsc/src/mat/utils/freespace.c (revision 3f2090d5b101f83ad3b99db560935e7511b462d0)
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 && bi[row+1] <= total) {
86       /* copy array entries into bj for this row */
87       nnz  = bi[row+1] - bi[row];
88       /* set bi[row] for new datastruct */
89       if (row == 0 ){
90         bi[row] = 0;
91       } else {
92         bi[row] = bi[row-1] + nnzL; /* nnzL of previous row */
93       }
94 
95       /* L part */
96       nnzL = bdiag[row];
97       bj   = space+bi[row];
98       ierr = PetscMemcpy(bj,array,nnzL*sizeof(PetscInt));CHKERRQ(ierr);
99 
100       /* diagonal entry */
101       bdiag[row] = bi_temp - 1;
102       space[bdiag[row]] = row;
103 
104       /* U part */
105       nnzU        = nnz - nnzL;
106       bi_temp = bi_temp - nnzU;
107       nnzU --;      /* exclude diagonal */
108       bj = space + bi_temp;
109       ierr = PetscMemcpy(bj,array+nnzL+1,nnzU*sizeof(PetscInt));CHKERRQ(ierr);
110       array += nnz;
111       row++;
112     }
113 
114     a     = (*head)->more_space;
115     ierr  = PetscFree((*head)->array_head);CHKERRQ(ierr);
116     ierr  = PetscFree(*head);CHKERRQ(ierr);
117     *head = a;
118   }
119   bi[n] = bi[n-1] + nnzL;
120   bdiag[n] = bdiag[n-1]-1;
121   PetscFunctionReturn(0);
122 }
123 
124 /*
125   PetscFreeSpaceContiguous_Cholesky -
126     Copy a linket list obtained from matrix symbolic ICC or Cholesky factorization into a contiguous array
127   that enables an efficient matrix triangular solve.
128 
129    Input Parameters:
130 +  head - linked list of column indices obtained from matrix symbolic ICC or Cholesky factorization
131 .  space - an allocated int array with length nnz of factored matrix.
132 .  n - order of the matrix
133 .  ui - row pointer of factored matrix with length n+1. All entries are set based on the traditional layout U matrix.
134 -  udiag - int array of length n.
135 
136    Output Parameter:
137 +  space - column indices are copied into this int array with contiguous layout of U, with diagonal located as the last entry in each row
138 -  udiag - indices of diagonal entries
139 
140    See MatICCFactorSymbolic_SeqAIJ_newdatastruct() for detailed description.
141 */
142 
143 #undef __FUNCT__
144 #define __FUNCT__ "PetscFreeSpaceContiguous_Cholesky"
145 PetscErrorCode PetscFreeSpaceContiguous_Cholesky(PetscFreeSpaceList *head,PetscInt *space,PetscInt n,PetscInt *ui,PetscInt *udiag)
146 {
147   PetscFreeSpaceList a;
148   PetscErrorCode     ierr;
149   PetscInt           row,nnz,*uj,*array,total;
150 
151   PetscFunctionBegin;
152   row   = 0;
153   total = 0;
154   while ((*head)!=NULL) {
155     total += (*head)->local_used;
156     array  = (*head)->array_head;
157 
158     while (ui[row+1] <= total && row < n){
159       udiag[row] = ui[row+1] - 1;     /* points to the last entry of U(row,:) */
160       nnz  = ui[row+1] - ui[row] - 1; /* exclude diagonal */
161       uj   = space + ui[row];
162       ierr = PetscMemcpy(uj,array+1,nnz*sizeof(PetscInt));CHKERRQ(ierr);
163       uj[nnz] = array[0]; /* diagonal */
164       array += nnz + 1;
165       row++;
166     }
167 
168     a     = (*head)->more_space;
169     ierr  = PetscFree((*head)->array_head);CHKERRQ(ierr);
170     ierr  = PetscFree(*head);CHKERRQ(ierr);
171     *head = a;
172   }
173   PetscFunctionReturn(0);
174 }
175 
176 #undef __FUNCT__
177 #define __FUNCT__ "PetscFreeSpaceDestroy"
178 PetscErrorCode PetscFreeSpaceDestroy(PetscFreeSpaceList head)
179 {
180   PetscFreeSpaceList a;
181   PetscErrorCode     ierr;
182 
183   PetscFunctionBegin;
184   while ((head)!=NULL) {
185     a    = (head)->more_space;
186     ierr = PetscFree((head)->array_head);CHKERRQ(ierr);
187     ierr = PetscFree(head);CHKERRQ(ierr);
188     head = a;
189   }
190   PetscFunctionReturn(0);
191 }
192