Actual source code: daltol.c
petsc-3.10.5 2019-03-28
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      2: /*
      3:   Code for manipulating distributed regular arrays in parallel.
      4: */

      6:  #include <petsc/private/dmdaimpl.h>

      8: /*
      9:    DMLocalToLocalCreate_DA - Creates the local to local scatter

     11:    Collective on DMDA

     13:    Input Parameter:
     14: .  da - the distributed array

     16: */
     17: PetscErrorCode  DMLocalToLocalCreate_DA(DM da)
     18: {
     20:   PetscInt       *idx,left,j,count,up,down,i,bottom,top,k,dim=da->dim;
     21:   DM_DA          *dd = (DM_DA*)da->data;

     26:   if (dd->ltol) return(0);
     27:   /*
     28:      We simply remap the values in the from part of
     29:      global to local to read from an array with the ghost values
     30:      rather then from the plain array.
     31:   */
     32:   VecScatterCopy(dd->gtol,&dd->ltol);
     33:   PetscLogObjectParent((PetscObject)da,(PetscObject)dd->ltol);
     34:   if (dim == 1) {
     35:     left = dd->xs - dd->Xs;
     36:     PetscMalloc1(dd->xe-dd->xs,&idx);
     37:     for (j=0; j<dd->xe-dd->xs; j++) idx[j] = left + j;
     38:   } else if (dim == 2) {
     39:     left  = dd->xs - dd->Xs; down  = dd->ys - dd->Ys; up    = down + dd->ye-dd->ys;
     40:     PetscMalloc1((dd->xe-dd->xs)*(up - down),&idx);
     41:     count = 0;
     42:     for (i=down; i<up; i++) {
     43:       for (j=0; j<dd->xe-dd->xs; j++) {
     44:         idx[count++] = left + i*(dd->Xe-dd->Xs) + j;
     45:       }
     46:     }
     47:   } else if (dim == 3) {
     48:     left   = dd->xs - dd->Xs;
     49:     bottom = dd->ys - dd->Ys; top = bottom + dd->ye-dd->ys;
     50:     down   = dd->zs - dd->Zs; up  = down + dd->ze-dd->zs;
     51:     count  = (dd->xe-dd->xs)*(top-bottom)*(up-down);
     52:     PetscMalloc1(count,&idx);
     53:     count  = 0;
     54:     for (i=down; i<up; i++) {
     55:       for (j=bottom; j<top; j++) {
     56:         for (k=0; k<dd->xe-dd->xs; k++) {
     57:           idx[count++] = (left+j*(dd->Xe-dd->Xs))+i*(dd->Xe-dd->Xs)*(dd->Ye-dd->Ys) + k;
     58:         }
     59:       }
     60:     }
     61:   } else SETERRQ1(PetscObjectComm((PetscObject)da),PETSC_ERR_ARG_CORRUPT,"DMDA has invalid dimension %D",dim);

     63:   VecScatterRemap(dd->ltol,idx,NULL);
     64:   PetscFree(idx);
     65:   return(0);
     66: }

     68: /*
     69:    DMLocalToLocalBegin_DA - Maps from a local vector (including ghost points
     70:    that contain irrelevant values) to another local vector where the ghost
     71:    points in the second are set correctly. Must be followed by DMLocalToLocalEnd_DA().

     73:    Neighbor-wise Collective on DMDA and Vec

     75:    Input Parameters:
     76: +  da - the distributed array context
     77: .  g - the original local vector
     78: -  mode - one of INSERT_VALUES or ADD_VALUES

     80:    Output Parameter:
     81: .  l  - the local vector with correct ghost values

     83:    Notes:
     84:    The local vectors used here need not be the same as those
     85:    obtained from DMCreateLocalVector(), BUT they
     86:    must have the same parallel data layout; they could, for example, be
     87:    obtained with VecDuplicate() from the DMDA originating vectors.

     89: */
     90: PetscErrorCode  DMLocalToLocalBegin_DA(DM da,Vec g,InsertMode mode,Vec l)
     91: {
     93:   DM_DA          *dd = (DM_DA*)da->data;

     97:   if (!dd->ltol) {
     98:     DMLocalToLocalCreate_DA(da);
     99:   }
    100:   VecScatterBegin(dd->ltol,g,l,mode,SCATTER_FORWARD);
    101:   return(0);
    102: }

    104: /*
    105:    DMLocalToLocalEnd_DA - Maps from a local vector (including ghost points
    106:    that contain irrelevant values) to another local vector where the ghost
    107:    points in the second are set correctly.  Must be preceeded by
    108:    DMLocalToLocalBegin_DA().

    110:    Neighbor-wise Collective on DMDA and Vec

    112:    Input Parameters:
    113: +  da - the distributed array context
    114: .  g - the original local vector
    115: -  mode - one of INSERT_VALUES or ADD_VALUES

    117:    Output Parameter:
    118: .  l  - the local vector with correct ghost values

    120:    Note:
    121:    The local vectors used here need not be the same as those
    122:    obtained from DMCreateLocalVector(), BUT they
    123:    must have the same parallel data layout; they could, for example, be
    124:    obtained with VecDuplicate() from the DMDA originating vectors.

    126: */
    127: PetscErrorCode  DMLocalToLocalEnd_DA(DM da,Vec g,InsertMode mode,Vec l)
    128: {
    130:   DM_DA          *dd = (DM_DA*)da->data;

    136:   VecScatterEnd(dd->ltol,g,l,mode,SCATTER_FORWARD);
    137:   return(0);
    138: }