2: /*
  3:   Code for manipulating distributed regular arrays in parallel.
  4: */

  6: #include <petsc-private/dmdaimpl.h>    /*I   "petscdmda.h"   I*/

 10: /*@C
 11:    DMDAGetGlobalIndices - Returns the global node number of all local nodes,
 12:    including ghost nodes.

 14:    Not Collective

 16:    Input Parameter:
 17: .  da - the distributed array

 19:    Output Parameters:
 20: +  n - the number of local elements, including ghost nodes (or NULL)
 21: -  idx - the global indices

 23:    Level: intermediate

 25:    Note:
 26:    For DMDA_STENCIL_STAR stencils the inactive corner ghost nodes are also included
 27:    in the list of local indices (even though those nodes are not updated
 28:    during calls to DMDAXXXToXXX().

 30:    Essentially the same data is returned in the form of a local-to-global mapping
 31:    with the routine DMDAGetISLocalToGlobalMapping();

 33:    Fortran Note:
 34:    This routine is used differently from Fortran
 35: .vb
 36:         DM          da
 37:         integer     n,da_array(1)
 38:         PetscOffset i_da
 39:         integer     ierr
 40:         call DMDAGetGlobalIndices(da,n,da_array,i_da,ierr)

 42:    C Access first local entry in list
 43:         value = da_array(i_da + 1)
 44: .ve

 46:    See the <A href="../../docs/manual.pdf#nameddest=Chapter 9 PETSc for Fortran Users">Fortran chapter</A> of the users manual for details.

 48: .keywords: distributed array, get, global, indices, local-to-global

 50: .seealso: DMDACreate2d(), DMDAGetGhostCorners(), DMDAGetCorners(), DMLocalToGlobalBegin()
 51:           DMGlobalToLocalBegin(), DMGlobalToLocalEnd(), DMDALocalToLocalBegin(), DMDAGetAO(), DMDAGetGlobalIndicesF90()
 52:           DMDAGetISLocalToGlobalMapping(), DMDACreate3d(), DMDACreate1d(), DMDALocalToLocalEnd(), DMDAGetOwnershipRanges()
 53: @*/
 54: PetscErrorCode  DMDAGetGlobalIndices(DM da,PetscInt *n,PetscInt **idx)
 55: {
 56:   DM_DA *dd = (DM_DA*)da->data;

 60:   if (n) *n = dd->Nl;
 61:   if (idx) *idx = dd->idx;
 62:   return(0);
 63: }

 67: /*
 68:    Gets the natural number for each global number on the process.

 70:    Used by DMDAGetAO() and DMDAGlobalToNatural_Create()
 71: */
 72: PetscErrorCode DMDAGetNatural_Private(DM da,PetscInt *outNlocal,IS *isnatural)
 73: {
 75:   PetscInt       Nlocal,i,j,k,*lidx,lict = 0;
 76:   DM_DA          *dd = (DM_DA*)da->data;

 79:   Nlocal = (dd->xe-dd->xs);
 80:   if (dd->dim > 1) Nlocal *= (dd->ye-dd->ys);
 81:   if (dd->dim > 2) Nlocal *= (dd->ze-dd->zs);

 83:   PetscMalloc(Nlocal*sizeof(PetscInt),&lidx);

 85:   if (dd->dim == 1) {
 86:     for (i=dd->xs; i<dd->xe; i++) {
 87:       /*  global number in natural ordering */
 88:       lidx[lict++] = i;
 89:     }
 90:   } else if (dd->dim == 2) {
 91:     for (j=dd->ys; j<dd->ye; j++) {
 92:       for (i=dd->xs; i<dd->xe; i++) {
 93:         /*  global number in natural ordering */
 94:         lidx[lict++] = i + j*dd->M*dd->w;
 95:       }
 96:     }
 97:   } else if (dd->dim == 3) {
 98:     for (k=dd->zs; k<dd->ze; k++) {
 99:       for (j=dd->ys; j<dd->ye; j++) {
100:         for (i=dd->xs; i<dd->xe; i++) {
101:           lidx[lict++] = i + j*dd->M*dd->w + k*dd->M*dd->N*dd->w;
102:         }
103:       }
104:     }
105:   }
106:   *outNlocal = Nlocal;
107:   ISCreateGeneral(PetscObjectComm((PetscObject)da),Nlocal,lidx,PETSC_OWN_POINTER,isnatural);
108:   return(0);
109: }

113: /*@
114:    DMDAGetAO - Gets the application ordering context for a distributed array.

116:    Collective on DMDA

118:    Input Parameter:
119: .  da - the distributed array

121:    Output Parameters:
122: .  ao - the application ordering context for DMDAs

124:    Level: intermediate

126:    Notes:
127:    In this case, the AO maps to the natural grid ordering that would be used
128:    for the DMDA if only 1 processor were employed (ordering most rapidly in the
129:    x-direction, then y, then z).  Multiple degrees of freedom are numbered
130:    for each node (rather than 1 component for the whole grid, then the next
131:    component, etc.)

133: .keywords: distributed array, get, global, indices, local-to-global

135: .seealso: DMDACreate2d(), DMDAGetGhostCorners(), DMDAGetCorners(), DMDALocalToGlocal()
136:           DMGlobalToLocalBegin(), DMGlobalToLocalEnd(), DMDALocalToLocalBegin(), DMDALocalToLocalEnd(), DMDAGetGlobalIndices(), DMDAGetOwnershipRanges(),
137:           AO, AOPetscToApplication(), AOApplicationToPetsc()
138: @*/
139: PetscErrorCode  DMDAGetAO(DM da,AO *ao)
140: {
141:   DM_DA *dd = (DM_DA*)da->data;


147:   /*
148:      Build the natural ordering to PETSc ordering mappings.
149:   */
150:   if (!dd->ao) {
151:     IS             ispetsc,isnatural;
153:     PetscInt       Nlocal;

155:     DMDAGetNatural_Private(da,&Nlocal,&isnatural);
156:     ISCreateStride(PetscObjectComm((PetscObject)da),Nlocal,dd->base,1,&ispetsc);
157:     AOCreateBasicIS(isnatural,ispetsc,&dd->ao);
158:     PetscLogObjectParent(da,dd->ao);
159:     ISDestroy(&ispetsc);
160:     ISDestroy(&isnatural);
161:   }
162:   *ao = dd->ao;
163:   return(0);
164: }

166: /*MC
167:     DMDAGetGlobalIndicesF90 - Returns a Fortran90 pointer to the list of
168:     global indices (global node number of all local nodes, including
169:     ghost nodes).

171:     Synopsis:
172:     DMDAGetGlobalIndicesF90(DM da,integer n,{integer, pointer :: idx(:)},integer ierr)

174:     Not Collective

176:     Input Parameter:
177: .   da - the distributed array

179:     Output Parameters:
180: +   n - the number of local elements, including ghost nodes (or NULL)
181: .   idx - the Fortran90 pointer to the global indices
182: -   ierr - error code

184:     Level: intermediate

186:     Notes:
187:      Not yet supported for all F90 compilers

189: .keywords: distributed array, get, global, indices, local-to-global, f90

191: .seealso: DMDAGetGlobalIndices()
192: M*/