xref: /petsc/src/mat/impls/sell/seq/fdsell.c (revision 3d77ad52841f320b3f6ad02ce14f35e73e722480)

#include <../src/mat/impls/sell/seq/sell.h>
#include <../src/mat/impls/aij/seq/aij.h>
#include <petsc/private/isimpl.h>

/*
 MatGetColumnIJ_SeqSELL_Color() and MatRestoreColumnIJ_SeqSELL_Color() are customized from
 MatGetColumnIJ_SeqSELL() and MatRestoreColumnIJ_SeqSELL() by adding an output
 spidx[], index of a->a, to be used in MatTransposeColoringCreate_SeqSELL() and MatFDColoringCreate_SeqSELL()
*/
PetscErrorCode MatGetColumnIJ_SeqSELL_Color(Mat A, PetscInt oshift, PetscBool symmetric, PetscBool inodecompressed, PetscInt *nn, const PetscInt *ia[], const PetscInt *ja[], PetscInt *spidx[], PetscBool *done)
{
  Mat_SeqSELL *a = (Mat_SeqSELL *)A->data;
  PetscInt     i, j, *collengths, *cia, *cja, n = A->cmap->n, totalslices;
  PetscInt     row, col;
  PetscInt    *cspidx;
  PetscBool    isnonzero;

  PetscFunctionBegin;
  PetscCheck(n >= 0, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Expected cmap->n %" PetscInt_FMT " >= 0", n);
  *nn = n;
  if (!ia) PetscFunctionReturn(PETSC_SUCCESS);

  PetscCall(PetscCalloc1(n, &collengths));
  PetscCall(PetscMalloc1(n + 1, &cia));
  PetscCall(PetscMalloc1(a->nz + 1, &cja));
  PetscCall(PetscMalloc1(a->nz + 1, &cspidx));

  totalslices = PetscCeilInt(A->rmap->n, 8);
  for (i = 0; i < totalslices; i++) { /* loop over slices */
    for (j = a->sliidx[i], row = 0; j < a->sliidx[i + 1]; j++, row = ((row + 1) & 0x07)) {
      isnonzero = (PetscBool)((j - a->sliidx[i]) / 8 < a->rlen[8 * i + row]);
      if (isnonzero) collengths[a->colidx[j]]++;
    }
  }

  cia[0] = oshift;
  for (i = 0; i < n; i++) cia[i + 1] = cia[i] + collengths[i];
  PetscCall(PetscArrayzero(collengths, n));

  for (i = 0; i < totalslices; i++) { /* loop over slices */
    for (j = a->sliidx[i], row = 0; j < a->sliidx[i + 1]; j++, row = ((row + 1) & 0x07)) {
      isnonzero = (PetscBool)((j - a->sliidx[i]) / 8 < a->rlen[8 * i + row]);
      if (isnonzero) {
        col                                         = a->colidx[j];
        cspidx[cia[col] + collengths[col] - oshift] = j;                    /* index of a->colidx */
        cja[cia[col] + collengths[col] - oshift]    = 8 * i + row + oshift; /* row index */
        collengths[col]++;
      }
    }
  }

  PetscCall(PetscFree(collengths));
  *ia    = cia;
  *ja    = cja;
  *spidx = cspidx;
  PetscFunctionReturn(PETSC_SUCCESS);
}

PetscErrorCode MatRestoreColumnIJ_SeqSELL_Color(Mat A, PetscInt oshift, PetscBool symmetric, PetscBool inodecompressed, PetscInt *n, const PetscInt *ia[], const PetscInt *ja[], PetscInt *spidx[], PetscBool *done)
{
  PetscFunctionBegin;
  if (!ia) PetscFunctionReturn(PETSC_SUCCESS);
  PetscCall(PetscFree(*ia));
  PetscCall(PetscFree(*ja));
  PetscCall(PetscFree(*spidx));
  PetscFunctionReturn(PETSC_SUCCESS);
}