1: #include <petsc/private/isimpl.h>
  2: #include <petscviewer.h>

  4: /*@
  5:   ISEqual  - Compares if two index sets have the same set of indices.

  7:   Collective

  9:   Input Parameters:
 10: + is1 - first index set to compare
 11: - is2 - second index set to compare

 13:   Output Parameter:
 14: . flg - output flag, either `PETSC_TRUE` (if both index sets have the
 15:          same indices), or `PETSC_FALSE` if the index sets differ by size
 16:          or by the set of indices)

 18:   Level: intermediate

 20:   Note:
 21:   Unlike `ISEqualUnsorted()`, this routine sorts the contents of the index sets (only within each MPI rank) before
 22:   the comparison is made, so the order of the indices on a processor is immaterial.

 24:   Each processor has to have the same indices in the two sets, for example,
 25: .vb
 26:            Processor
 27:              0      1
 28:     is1 = {0, 1} {2, 3}
 29:     is2 = {2, 3} {0, 1}
 30: .ve
 31:   will return false.

 33: .seealso: [](sec_scatter), `IS`, `ISEqualUnsorted()`
 34: @*/
 35: PetscErrorCode ISEqual(IS is1, IS is2, PetscBool *flg)
 36: {
 37:   PetscInt        sz1, sz2, *a1, *a2;
 38:   const PetscInt *ptr1, *ptr2;
 39:   MPI_Comm        comm;
 40:   PetscMPIInt     mflg;

 42:   PetscFunctionBegin;
 45:   PetscAssertPointer(flg, 3);

 47:   if (is1 == is2) {
 48:     *flg = PETSC_TRUE;
 49:     PetscFunctionReturn(PETSC_SUCCESS);
 50:   }

 52:   PetscCallMPI(MPI_Comm_compare(PetscObjectComm((PetscObject)is1), PetscObjectComm((PetscObject)is2), &mflg));
 53:   if (mflg != MPI_CONGRUENT && mflg != MPI_IDENT) {
 54:     *flg = PETSC_FALSE;
 55:     PetscFunctionReturn(PETSC_SUCCESS);
 56:   }

 58:   PetscCall(ISGetSize(is1, &sz1));
 59:   PetscCall(ISGetSize(is2, &sz2));
 60:   if (sz1 != sz2) *flg = PETSC_FALSE;
 61:   else {
 62:     PetscCall(ISGetLocalSize(is1, &sz1));
 63:     PetscCall(ISGetLocalSize(is2, &sz2));

 65:     if (sz1 != sz2) *flg = PETSC_FALSE;
 66:     else {
 67:       PetscCall(ISGetIndices(is1, &ptr1));
 68:       PetscCall(ISGetIndices(is2, &ptr2));

 70:       PetscCall(PetscMalloc1(sz1, &a1));
 71:       PetscCall(PetscMalloc1(sz2, &a2));

 73:       PetscCall(PetscArraycpy(a1, ptr1, sz1));
 74:       PetscCall(PetscArraycpy(a2, ptr2, sz2));

 76:       PetscCall(PetscIntSortSemiOrdered(sz1, a1));
 77:       PetscCall(PetscIntSortSemiOrdered(sz2, a2));
 78:       PetscCall(PetscArraycmp(a1, a2, sz1, flg));

 80:       PetscCall(ISRestoreIndices(is1, &ptr1));
 81:       PetscCall(ISRestoreIndices(is2, &ptr2));

 83:       PetscCall(PetscFree(a1));
 84:       PetscCall(PetscFree(a2));
 85:     }
 86:     PetscCall(PetscObjectGetComm((PetscObject)is1, &comm));
 87:     PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, flg, 1, MPI_C_BOOL, MPI_LAND, comm));
 88:   }
 89:   PetscFunctionReturn(PETSC_SUCCESS);
 90: }

 92: /*@
 93:   ISEqualUnsorted  - Compares if two index sets have the same indices.

 95:   Collective

 97:   Input Parameters:
 98: + is1 - first index set to compare
 99: - is2 - second index set to compare

101:   Output Parameter:
102: . flg - output flag, either `PETSC_TRUE` (if both index sets have the
103:          same indices), or `PETSC_FALSE` if the index sets differ by size
104:          or by the set of indices)

106:   Level: intermediate

108:   Note:
109:   Unlike `ISEqual()`, this routine does NOT sort the contents of the index sets before
110:   the comparison is made, i.e., the order of indices is important.

112:   Each MPI rank must have the same indices.

114: .seealso: [](sec_scatter), `IS`, `ISEqual()`
115: @*/
116: PetscErrorCode ISEqualUnsorted(IS is1, IS is2, PetscBool *flg)
117: {
118:   PetscInt        sz1, sz2;
119:   const PetscInt *ptr1, *ptr2;
120:   MPI_Comm        comm;
121:   PetscMPIInt     mflg;

123:   PetscFunctionBegin;
126:   PetscAssertPointer(flg, 3);

128:   if (is1 == is2) {
129:     *flg = PETSC_TRUE;
130:     PetscFunctionReturn(PETSC_SUCCESS);
131:   }

133:   PetscCallMPI(MPI_Comm_compare(PetscObjectComm((PetscObject)is1), PetscObjectComm((PetscObject)is2), &mflg));
134:   if (mflg != MPI_CONGRUENT && mflg != MPI_IDENT) {
135:     *flg = PETSC_FALSE;
136:     PetscFunctionReturn(PETSC_SUCCESS);
137:   }

139:   PetscCall(ISGetSize(is1, &sz1));
140:   PetscCall(ISGetSize(is2, &sz2));
141:   if (sz1 != sz2) *flg = PETSC_FALSE;
142:   else {
143:     PetscCall(ISGetLocalSize(is1, &sz1));
144:     PetscCall(ISGetLocalSize(is2, &sz2));

146:     if (sz1 != sz2) *flg = PETSC_FALSE;
147:     else {
148:       PetscCall(ISGetIndices(is1, &ptr1));
149:       PetscCall(ISGetIndices(is2, &ptr2));

151:       PetscCall(PetscArraycmp(ptr1, ptr2, sz1, flg));

153:       PetscCall(ISRestoreIndices(is1, &ptr1));
154:       PetscCall(ISRestoreIndices(is2, &ptr2));
155:     }
156:     PetscCall(PetscObjectGetComm((PetscObject)is1, &comm));
157:     PetscCallMPI(MPIU_Allreduce(MPI_IN_PLACE, flg, 1, MPI_C_BOOL, MPI_LAND, comm));
158:   }
159:   PetscFunctionReturn(PETSC_SUCCESS);
160: }