Actual source code: freespace.c
petsc-3.7.1 2016-05-15
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      2: #include <../src/mat/utils/freespace.h>

      6: PetscErrorCode PetscFreeSpaceGet(PetscInt n,PetscFreeSpaceList *list)
      7: {
      8:   PetscFreeSpaceList a;
      9:   PetscErrorCode     ierr;

     12:   PetscMalloc(sizeof(struct _Space),&a);
     13:   PetscMalloc1(n,&(a->array_head));

     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;

     21:   if (*list) {
     22:     (*list)->more_space = a;
     23:     a->total_array_size = (*list)->total_array_size;
     24:   }

     26:   a->total_array_size += n;
     27:   *list                =  a;
     28:   return(0);
     29: }

     33: PetscErrorCode PetscFreeSpaceContiguous(PetscFreeSpaceList *head,PetscInt *space)
     34: {
     35:   PetscFreeSpaceList a;
     36:   PetscErrorCode     ierr;

     39:   while ((*head)) {
     40:     a      =  (*head)->more_space;
     41:      PetscMemcpy(space,(*head)->array_head,((*head)->local_used)*sizeof(PetscInt));
     42:     space += (*head)->local_used;
     43:      PetscFree((*head)->array_head);
     44:      PetscFree(*head);
     45:     *head  =  a;
     46:   }
     47:   return(0);
     48: }

     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.

     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.

     62:    Output Parameter:
     63: .  space - column indices are copied into this int array with contiguous layout of L and U

     65:    See MatILUFactorSymbolic_SeqAIJ_ilu0() for detailed data structure of L and U
     66: */
     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;

     77:   bi_temp = bi[n];
     78:   row     = 0;
     79:   total   = 0;
     80:   nnzL    = bdiag[0];
     81:   while ((*head)) {
     82:     total += (*head)->local_used;
     83:     array  = (*head)->array_head;

     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:       }

     96:       /* L part */
     97:       nnzL = bdiag[row];
     98:       bj   = space+bi[row];
     99:       PetscMemcpy(bj,array,nnzL*sizeof(PetscInt));

    101:       /* diagonal entry */
    102:       bdiag[row]        = bi_temp - 1;
    103:       space[bdiag[row]] = row;

    105:       /* U part */
    106:       nnzU    = nnz - nnzL;
    107:       bi_temp = bi_temp - nnzU;
    108:       nnzU--;       /* exclude diagonal */
    109:       bj     = space + bi_temp;
    110:       PetscMemcpy(bj,array+nnzL+1,nnzU*sizeof(PetscInt));
    111:       array += nnz;
    112:       row++;
    113:     }

    115:     a     = (*head)->more_space;
    116:     PetscFree((*head)->array_head);
    117:     PetscFree(*head);
    118:     *head = a;
    119:   }
    120:   if (n) {
    121:     bi[n]    = bi[n-1] + nnzL;
    122:     bdiag[n] = bdiag[n-1]-1;
    123:   }
    124:   return(0);
    125: }

    127: /*
    128:   PetscFreeSpaceContiguous_Cholesky -
    129:     Copy a linket list obtained from matrix symbolic ICC or Cholesky factorization into a contiguous array
    130:   that enables an efficient matrix triangular solve.

    132:    Input Parameters:
    133: +  head - linked list of column indices obtained from matrix symbolic ICC or Cholesky factorization
    134: .  space - an allocated int array with length nnz of factored matrix.
    135: .  n - order of the matrix
    136: .  ui - row pointer of factored matrix with length n+1. All entries are set based on the traditional layout U matrix.
    137: -  udiag - int array of length n.

    139:    Output Parameter:
    140: +  space - column indices are copied into this int array with contiguous layout of U, with diagonal located as the last entry in each row
    141: -  udiag - indices of diagonal entries

    143:    See MatICCFactorSymbolic_SeqAIJ_newdatastruct() for detailed description.
    144: */

    148: PetscErrorCode PetscFreeSpaceContiguous_Cholesky(PetscFreeSpaceList *head,PetscInt *space,PetscInt n,PetscInt *ui,PetscInt *udiag)
    149: {
    150:   PetscFreeSpaceList a;
    151:   PetscErrorCode     ierr;
    152:   PetscInt           row,nnz,*uj,*array,total;

    155:   row   = 0;
    156:   total = 0;
    157:   while (*head) {
    158:     total += (*head)->local_used;
    159:     array  = (*head)->array_head;

    161:     while (row < n) {
    162:       if (ui[row+1] > total) break;
    163:       udiag[row] = ui[row+1] - 1;     /* points to the last entry of U(row,:) */
    164:       nnz        = ui[row+1] - ui[row] - 1; /* exclude diagonal */
    165:       uj         = space + ui[row];
    166:       PetscMemcpy(uj,array+1,nnz*sizeof(PetscInt));
    167:       uj[nnz]    = array[0]; /* diagonal */
    168:       array     += nnz + 1;
    169:       row++;
    170:     }

    172:     a     = (*head)->more_space;
    173:     PetscFree((*head)->array_head);
    174:     PetscFree(*head);
    175:     *head = a;
    176:   }
    177:   return(0);
    178: }

    182: PetscErrorCode PetscFreeSpaceDestroy(PetscFreeSpaceList head)
    183: {
    184:   PetscFreeSpaceList a;
    185:   PetscErrorCode     ierr;

    188:   while ((head)) {
    189:     a    = (head)->more_space;
    190:     PetscFree((head)->array_head);
    191:     PetscFree(head);
    192:     head = a;
    193:   }
    194:   return(0);
    195: }