xref: /petsc/src/ksp/pc/impls/tfs/ivec.c (revision 9371c9d470a9602b6d10a8bf50c9b2280a79e45a)

/**********************************ivec.c**************************************

Author: Henry M. Tufo III

e-mail: hmt@cs.brown.edu

snail-mail:
Division of Applied Mathematics
Brown University
Providence, RI 02912

Last Modification:
6.21.97
***********************************ivec.c*************************************/

#include <../src/ksp/pc/impls/tfs/tfs.h>

/* sorting args ivec.c ivec.c ... */
#define SORT_OPT   6
#define SORT_STACK 50000

/* allocate an address and size stack for sorter(s) */
static void    *offset_stack[2 * SORT_STACK];
static PetscInt size_stack[SORT_STACK];

/***********************************ivec.c*************************************/
PetscInt *PCTFS_ivec_copy(PetscInt *arg1, PetscInt *arg2, PetscInt n) {
  while (n--) *arg1++ = *arg2++;
  return (arg1);
}

/***********************************ivec.c*************************************/
PetscErrorCode PCTFS_ivec_zero(PetscInt *arg1, PetscInt n) {
  PetscFunctionBegin;
  while (n--) *arg1++ = 0;
  PetscFunctionReturn(0);
}

/***********************************ivec.c*************************************/
PetscErrorCode PCTFS_ivec_set(PetscInt *arg1, PetscInt arg2, PetscInt n) {
  PetscFunctionBegin;
  while (n--) *arg1++ = arg2;
  PetscFunctionReturn(0);
}

/***********************************ivec.c*************************************/
PetscErrorCode PCTFS_ivec_max(PetscInt *arg1, PetscInt *arg2, PetscInt n) {
  PetscFunctionBegin;
  while (n--) {
    *arg1 = PetscMax(*arg1, *arg2);
    arg1++;
    arg2++;
  }
  PetscFunctionReturn(0);
}

/***********************************ivec.c*************************************/
PetscErrorCode PCTFS_ivec_min(PetscInt *arg1, PetscInt *arg2, PetscInt n) {
  PetscFunctionBegin;
  while (n--) {
    *(arg1) = PetscMin(*arg1, *arg2);
    arg1++;
    arg2++;
  }
  PetscFunctionReturn(0);
}

/***********************************ivec.c*************************************/
PetscErrorCode PCTFS_ivec_mult(PetscInt *arg1, PetscInt *arg2, PetscInt n) {
  PetscFunctionBegin;
  while (n--) *arg1++ *= *arg2++;
  PetscFunctionReturn(0);
}

/***********************************ivec.c*************************************/
PetscErrorCode PCTFS_ivec_add(PetscInt *arg1, PetscInt *arg2, PetscInt n) {
  PetscFunctionBegin;
  while (n--) *arg1++ += *arg2++;
  PetscFunctionReturn(0);
}

/***********************************ivec.c*************************************/
PetscErrorCode PCTFS_ivec_lxor(PetscInt *arg1, PetscInt *arg2, PetscInt n) {
  PetscFunctionBegin;
  while (n--) {
    *arg1 = ((*arg1 || *arg2) && !(*arg1 && *arg2));
    arg1++;
    arg2++;
  }
  PetscFunctionReturn(0);
}

/***********************************ivec.c*************************************/
PetscErrorCode PCTFS_ivec_xor(PetscInt *arg1, PetscInt *arg2, PetscInt n) {
  PetscFunctionBegin;
  while (n--) *arg1++ ^= *arg2++;
  PetscFunctionReturn(0);
}

/***********************************ivec.c*************************************/
PetscErrorCode PCTFS_ivec_or(PetscInt *arg1, PetscInt *arg2, PetscInt n) {
  PetscFunctionBegin;
  while (n--) *arg1++ |= *arg2++;
  PetscFunctionReturn(0);
}

/***********************************ivec.c*************************************/
PetscErrorCode PCTFS_ivec_lor(PetscInt *arg1, PetscInt *arg2, PetscInt n) {
  PetscFunctionBegin;
  while (n--) {
    *arg1 = (*arg1 || *arg2);
    arg1++;
    arg2++;
  }
  PetscFunctionReturn(0);
}

/***********************************ivec.c*************************************/
PetscErrorCode PCTFS_ivec_and(PetscInt *arg1, PetscInt *arg2, PetscInt n) {
  PetscFunctionBegin;
  while (n--) *arg1++ &= *arg2++;
  PetscFunctionReturn(0);
}

/***********************************ivec.c*************************************/
PetscErrorCode PCTFS_ivec_land(PetscInt *arg1, PetscInt *arg2, PetscInt n) {
  PetscFunctionBegin;
  while (n--) {
    *arg1 = (*arg1 && *arg2);
    arg1++;
    arg2++;
  }
  PetscFunctionReturn(0);
}

/***********************************ivec.c*************************************/
PetscErrorCode PCTFS_ivec_and3(PetscInt *arg1, PetscInt *arg2, PetscInt *arg3, PetscInt n) {
  PetscFunctionBegin;
  while (n--) *arg1++ = (*arg2++ & *arg3++);
  PetscFunctionReturn(0);
}

/***********************************ivec.c*************************************/
PetscInt PCTFS_ivec_sum(PetscInt *arg1, PetscInt n) {
  PetscInt tmp = 0;
  while (n--) tmp += *arg1++;
  return (tmp);
}

/***********************************ivec.c*************************************/
PetscErrorCode PCTFS_ivec_non_uniform(PetscInt *arg1, PetscInt *arg2, PetscInt n, ...) {
  PetscInt  i, j, type;
  PetscInt *arg3;
  va_list   ap;

  PetscFunctionBegin;
  va_start(ap, n);
  arg3 = va_arg(ap, PetscInt *);
  va_end(ap);

  /* LATER: if we're really motivated we can sort and then unsort */
  for (i = 0; i < n;) {
    /* clump 'em for now */
    j    = i + 1;
    type = arg3[i];
    while ((j < n) && (arg3[j] == type)) j++;

    /* how many together */
    j -= i;

    /* call appropriate ivec function */
    if (type == GL_MAX) PCTFS_ivec_max(arg1, arg2, j);
    else if (type == GL_MIN) PCTFS_ivec_min(arg1, arg2, j);
    else if (type == GL_MULT) PCTFS_ivec_mult(arg1, arg2, j);
    else if (type == GL_ADD) PCTFS_ivec_add(arg1, arg2, j);
    else if (type == GL_B_XOR) PCTFS_ivec_xor(arg1, arg2, j);
    else if (type == GL_B_OR) PCTFS_ivec_or(arg1, arg2, j);
    else if (type == GL_B_AND) PCTFS_ivec_and(arg1, arg2, j);
    else if (type == GL_L_XOR) PCTFS_ivec_lxor(arg1, arg2, j);
    else if (type == GL_L_OR) PCTFS_ivec_lor(arg1, arg2, j);
    else if (type == GL_L_AND) PCTFS_ivec_land(arg1, arg2, j);
    else SETERRQ(PETSC_COMM_SELF, PETSC_ERR_PLIB, "unrecognized type passed to PCTFS_ivec_non_uniform()!");

    arg1 += j;
    arg2 += j;
    i += j;
  }
  PetscFunctionReturn(0);
}

/***********************************ivec.c*************************************/
vfp PCTFS_ivec_fct_addr(PetscInt type) {
  if (type == NON_UNIFORM) return ((PetscErrorCode(*)(void *, void *, PetscInt, ...)) & PCTFS_ivec_non_uniform);
  else if (type == GL_MAX) return ((PetscErrorCode(*)(void *, void *, PetscInt, ...)) & PCTFS_ivec_max);
  else if (type == GL_MIN) return ((PetscErrorCode(*)(void *, void *, PetscInt, ...)) & PCTFS_ivec_min);
  else if (type == GL_MULT) return ((PetscErrorCode(*)(void *, void *, PetscInt, ...)) & PCTFS_ivec_mult);
  else if (type == GL_ADD) return ((PetscErrorCode(*)(void *, void *, PetscInt, ...)) & PCTFS_ivec_add);
  else if (type == GL_B_XOR) return ((PetscErrorCode(*)(void *, void *, PetscInt, ...)) & PCTFS_ivec_xor);
  else if (type == GL_B_OR) return ((PetscErrorCode(*)(void *, void *, PetscInt, ...)) & PCTFS_ivec_or);
  else if (type == GL_B_AND) return ((PetscErrorCode(*)(void *, void *, PetscInt, ...)) & PCTFS_ivec_and);
  else if (type == GL_L_XOR) return ((PetscErrorCode(*)(void *, void *, PetscInt, ...)) & PCTFS_ivec_lxor);
  else if (type == GL_L_OR) return ((PetscErrorCode(*)(void *, void *, PetscInt, ...)) & PCTFS_ivec_lor);
  else if (type == GL_L_AND) return ((PetscErrorCode(*)(void *, void *, PetscInt, ...)) & PCTFS_ivec_land);

  /* catch all ... not good if we get here */
  return (NULL);
}

/******************************************************************************/
PetscErrorCode PCTFS_ivec_sort(PetscInt *ar, PetscInt size) {
  PetscInt  *pi, *pj, temp;
  PetscInt **top_a = (PetscInt **)offset_stack;
  PetscInt  *top_s = size_stack, *bottom_s = size_stack;

  PetscFunctionBegin;
  /* we're really interested in the offset of the last element */
  /* ==> length of the list is now size + 1                    */
  size--;

  /* do until we're done ... return when stack is exhausted */
  for (;;) {
    /* if list is large enough use quicksort partition exchange code */
    if (size > SORT_OPT) {
      /* start up pointer at element 1 and down at size     */
      pi = ar + 1;
      pj = ar + size;

      /* find middle element in list and swap w/ element 1 */
      SWAP(*(ar + (size >> 1)), *pi)

      /* order element 0,1,size-1 st {M,L,...,U} w/L<=M<=U */
      /* note ==> pivot_value in index 0                   */
      if (*pi > *pj) { SWAP(*pi, *pj) }
      if (*ar > *pj) {
        SWAP(*ar, *pj)
      } else if (*pi > *ar) {
        SWAP(*(ar), *(ar + 1))
      }

      /* partition about pivot_value ...                              */
      /* note lists of length 2 are not guaranteed to be sorted */
      for (;;) {
        /* walk up ... and down ... swap if equal to pivot! */
        do pi++;
        while (*pi < *ar);
        do pj--;
        while (*pj > *ar);

        /* if we've crossed we're done */
        if (pj < pi) break;

        /* else swap */
        SWAP(*pi, *pj)
      }

      /* place pivot_value in it's correct location */
      SWAP(*ar, *pj)

      /* test stack_size to see if we've exhausted our stack */
      PetscCheck(top_s - bottom_s < SORT_STACK, PETSC_COMM_SELF, PETSC_ERR_PLIB, "PCTFS_ivec_sort() :: STACK EXHAUSTED!!!");

      /* push right hand child iff length > 1 */
      if ((*top_s = size - ((PetscInt)(pi - ar)))) {
        *(top_a++) = pi;
        size -= *top_s + 2;
        top_s++;
      } else if (size -= *top_s + 2)
        ; /* set up for next loop iff there is something to do */
      else { /* might as well pop - note NR_OPT >=2 ==> we're ok! */ ar = *(--top_a);
        size                                                            = *(--top_s);
      }
    } else { /* else sort small list directly then pop another off stack */

      /* insertion sort for bottom */
      for (pj = ar + 1; pj <= ar + size; pj++) {
        temp = *pj;
        for (pi = pj - 1; pi >= ar; pi--) {
          if (*pi <= temp) break;
          *(pi + 1) = *pi;
        }
        *(pi + 1) = temp;
      }

      /* check to see if stack is exhausted ==> DONE */
      if (top_s == bottom_s) PetscFunctionReturn(0);

      /* else pop another list from the stack */
      ar   = *(--top_a);
      size = *(--top_s);
    }
  }
}

/******************************************************************************/
PetscErrorCode PCTFS_ivec_sort_companion(PetscInt *ar, PetscInt *ar2, PetscInt size) {
  PetscInt  *pi, *pj, temp, temp2;
  PetscInt **top_a = (PetscInt **)offset_stack;
  PetscInt  *top_s = size_stack, *bottom_s = size_stack;
  PetscInt  *pi2, *pj2;
  PetscInt   mid;

  PetscFunctionBegin;
  /* we're really interested in the offset of the last element */
  /* ==> length of the list is now size + 1                    */
  size--;

  /* do until we're done ... return when stack is exhausted */
  for (;;) {
    /* if list is large enough use quicksort partition exchange code */
    if (size > SORT_OPT) {
      /* start up pointer at element 1 and down at size     */
      mid = size >> 1;
      pi  = ar + 1;
      pj  = ar + mid;
      pi2 = ar2 + 1;
      pj2 = ar2 + mid;

      /* find middle element in list and swap w/ element 1 */
      SWAP(*pi, *pj)
      SWAP(*pi2, *pj2)

      /* order element 0,1,size-1 st {M,L,...,U} w/L<=M<=U */
      /* note ==> pivot_value in index 0                   */
      pj  = ar + size;
      pj2 = ar2 + size;
      if (*pi > *pj) { SWAP(*pi, *pj) SWAP(*pi2, *pj2) }
      if (*ar > *pj) {
        SWAP(*ar, *pj) SWAP(*ar2, *pj2)
      } else if (*pi > *ar) {
        SWAP(*(ar), *(ar + 1)) SWAP(*(ar2), *(ar2 + 1))
      }

      /* partition about pivot_value ...                              */
      /* note lists of length 2 are not guaranteed to be sorted */
      for (;;) {
        /* walk up ... and down ... swap if equal to pivot! */
        do {
          pi++;
          pi2++;
        } while (*pi < *ar);
        do {
          pj--;
          pj2--;
        } while (*pj > *ar);

        /* if we've crossed we're done */
        if (pj < pi) break;

        /* else swap */
        SWAP(*pi, *pj)
        SWAP(*pi2, *pj2)
      }

      /* place pivot_value in it's correct location */
      SWAP(*ar, *pj)
      SWAP(*ar2, *pj2)

      /* test stack_size to see if we've exhausted our stack */
      PetscCheck(top_s - bottom_s < SORT_STACK, PETSC_COMM_SELF, PETSC_ERR_PLIB, "PCTFS_ivec_sort_companion() :: STACK EXHAUSTED!!!");

      /* push right hand child iff length > 1 */
      if ((*top_s = size - ((PetscInt)(pi - ar)))) {
        *(top_a++) = pi;
        *(top_a++) = pi2;
        size -= *top_s + 2;
        top_s++;
      } else if (size -= *top_s + 2)
        ; /* set up for next loop iff there is something to do */
      else { /* might as well pop - note NR_OPT >=2 ==> we're ok! */ ar2 = *(--top_a);
        ar                                                               = *(--top_a);
        size                                                             = *(--top_s);
      }
    } else { /* else sort small list directly then pop another off stack */

      /* insertion sort for bottom */
      for (pj = ar + 1, pj2 = ar2 + 1; pj <= ar + size; pj++, pj2++) {
        temp  = *pj;
        temp2 = *pj2;
        for (pi = pj - 1, pi2 = pj2 - 1; pi >= ar; pi--, pi2--) {
          if (*pi <= temp) break;
          *(pi + 1)  = *pi;
          *(pi2 + 1) = *pi2;
        }
        *(pi + 1)  = temp;
        *(pi2 + 1) = temp2;
      }

      /* check to see if stack is exhausted ==> DONE */
      if (top_s == bottom_s) PetscFunctionReturn(0);

      /* else pop another list from the stack */
      ar2  = *(--top_a);
      ar   = *(--top_a);
      size = *(--top_s);
    }
  }
}

/******************************************************************************/
PetscErrorCode PCTFS_ivec_sort_companion_hack(PetscInt *ar, PetscInt **ar2, PetscInt size) {
  PetscInt  *pi, *pj, temp, *ptr;
  PetscInt **top_a = (PetscInt **)offset_stack;
  PetscInt  *top_s = size_stack, *bottom_s = size_stack;
  PetscInt **pi2, **pj2;
  PetscInt   mid;

  PetscFunctionBegin;
  /* we're really interested in the offset of the last element */
  /* ==> length of the list is now size + 1                    */
  size--;

  /* do until we're done ... return when stack is exhausted */
  for (;;) {
    /* if list is large enough use quicksort partition exchange code */
    if (size > SORT_OPT) {
      /* start up pointer at element 1 and down at size     */
      mid = size >> 1;
      pi  = ar + 1;
      pj  = ar + mid;
      pi2 = ar2 + 1;
      pj2 = ar2 + mid;

      /* find middle element in list and swap w/ element 1 */
      SWAP(*pi, *pj)
      P_SWAP(*pi2, *pj2)

      /* order element 0,1,size-1 st {M,L,...,U} w/L<=M<=U */
      /* note ==> pivot_value in index 0                   */
      pj  = ar + size;
      pj2 = ar2 + size;
      if (*pi > *pj) { SWAP(*pi, *pj) P_SWAP(*pi2, *pj2) }
      if (*ar > *pj) {
        SWAP(*ar, *pj) P_SWAP(*ar2, *pj2)
      } else if (*pi > *ar) {
        SWAP(*(ar), *(ar + 1)) P_SWAP(*(ar2), *(ar2 + 1))
      }

      /* partition about pivot_value ...                              */
      /* note lists of length 2 are not guaranteed to be sorted */
      for (;;) {
        /* walk up ... and down ... swap if equal to pivot! */
        do {
          pi++;
          pi2++;
        } while (*pi < *ar);
        do {
          pj--;
          pj2--;
        } while (*pj > *ar);

        /* if we've crossed we're done */
        if (pj < pi) break;

        /* else swap */
        SWAP(*pi, *pj)
        P_SWAP(*pi2, *pj2)
      }

      /* place pivot_value in it's correct location */
      SWAP(*ar, *pj)
      P_SWAP(*ar2, *pj2)

      /* test stack_size to see if we've exhausted our stack */
      PetscCheck(top_s - bottom_s < SORT_STACK, PETSC_COMM_SELF, PETSC_ERR_PLIB, "PCTFS_ivec_sort_companion_hack() :: STACK EXHAUSTED!!!");

      /* push right hand child iff length > 1 */
      if ((*top_s = size - ((PetscInt)(pi - ar)))) {
        *(top_a++) = pi;
        *(top_a++) = (PetscInt *)pi2;
        size -= *top_s + 2;
        top_s++;
      } else if (size -= *top_s + 2)
        ; /* set up for next loop iff there is something to do */
      else { /* might as well pop - note NR_OPT >=2 ==> we're ok! */ ar2 = (PetscInt **)*(--top_a);
        ar                                                               = *(--top_a);
        size                                                             = *(--top_s);
      }
    } else { /* else sort small list directly then pop another off stack */
      /* insertion sort for bottom */
      for (pj = ar + 1, pj2 = ar2 + 1; pj <= ar + size; pj++, pj2++) {
        temp = *pj;
        ptr  = *pj2;
        for (pi = pj - 1, pi2 = pj2 - 1; pi >= ar; pi--, pi2--) {
          if (*pi <= temp) break;
          *(pi + 1)  = *pi;
          *(pi2 + 1) = *pi2;
        }
        *(pi + 1)  = temp;
        *(pi2 + 1) = ptr;
      }

      /* check to see if stack is exhausted ==> DONE */
      if (top_s == bottom_s) PetscFunctionReturn(0);

      /* else pop another list from the stack */
      ar2  = (PetscInt **)*(--top_a);
      ar   = *(--top_a);
      size = *(--top_s);
    }
  }
}

/******************************************************************************/
PetscErrorCode PCTFS_SMI_sort(void *ar1, void *ar2, PetscInt size, PetscInt type) {
  PetscFunctionBegin;
  if (type == SORT_INTEGER) {
    if (ar2) PCTFS_ivec_sort_companion((PetscInt *)ar1, (PetscInt *)ar2, size);
    else PCTFS_ivec_sort((PetscInt *)ar1, size);
  } else if (type == SORT_INT_PTR) {
    if (ar2) PCTFS_ivec_sort_companion_hack((PetscInt *)ar1, (PetscInt **)ar2, size);
    else PCTFS_ivec_sort((PetscInt *)ar1, size);
  } else SETERRQ(PETSC_COMM_SELF, PETSC_ERR_PLIB, "PCTFS_SMI_sort only does SORT_INTEGER!");
  PetscFunctionReturn(0);
}

/***********************************ivec.c*************************************/
PetscInt PCTFS_ivec_linear_search(PetscInt item, PetscInt *list, PetscInt n) {
  PetscInt tmp = n - 1;

  while (n--) {
    if (*list++ == item) return (tmp - n);
  }
  return (-1);
}

/***********************************ivec.c*************************************/
PetscInt PCTFS_ivec_binary_search(PetscInt item, PetscInt *list, PetscInt rh) {
  PetscInt mid, lh = 0;

  rh--;
  while (lh <= rh) {
    mid = (lh + rh) >> 1;
    if (*(list + mid) == item) return (mid);
    if (*(list + mid) > item) rh = mid - 1;
    else lh = mid + 1;
  }
  return (-1);
}

/*********************************ivec.c*************************************/
PetscErrorCode PCTFS_rvec_copy(PetscScalar *arg1, PetscScalar *arg2, PetscInt n) {
  PetscFunctionBegin;
  while (n--) *arg1++ = *arg2++;
  PetscFunctionReturn(0);
}

/*********************************ivec.c*************************************/
PetscErrorCode PCTFS_rvec_zero(PetscScalar *arg1, PetscInt n) {
  PetscFunctionBegin;
  while (n--) *arg1++ = 0.0;
  PetscFunctionReturn(0);
}

/***********************************ivec.c*************************************/
PetscErrorCode PCTFS_rvec_one(PetscScalar *arg1, PetscInt n) {
  PetscFunctionBegin;
  while (n--) *arg1++ = 1.0;
  PetscFunctionReturn(0);
}

/***********************************ivec.c*************************************/
PetscErrorCode PCTFS_rvec_set(PetscScalar *arg1, PetscScalar arg2, PetscInt n) {
  PetscFunctionBegin;
  while (n--) *arg1++ = arg2;
  PetscFunctionReturn(0);
}

/***********************************ivec.c*************************************/
PetscErrorCode PCTFS_rvec_scale(PetscScalar *arg1, PetscScalar arg2, PetscInt n) {
  PetscFunctionBegin;
  while (n--) *arg1++ *= arg2;
  PetscFunctionReturn(0);
}

/*********************************ivec.c*************************************/
PetscErrorCode PCTFS_rvec_add(PetscScalar *arg1, PetscScalar *arg2, PetscInt n) {
  PetscFunctionBegin;
  while (n--) *arg1++ += *arg2++;
  PetscFunctionReturn(0);
}

/*********************************ivec.c*************************************/
PetscErrorCode PCTFS_rvec_mult(PetscScalar *arg1, PetscScalar *arg2, PetscInt n) {
  PetscFunctionBegin;
  while (n--) *arg1++ *= *arg2++;
  PetscFunctionReturn(0);
}

/*********************************ivec.c*************************************/
PetscErrorCode PCTFS_rvec_max(PetscScalar *arg1, PetscScalar *arg2, PetscInt n) {
  PetscFunctionBegin;
  while (n--) {
    *arg1 = PetscMax(*arg1, *arg2);
    arg1++;
    arg2++;
  }
  PetscFunctionReturn(0);
}

/*********************************ivec.c*************************************/
PetscErrorCode PCTFS_rvec_max_abs(PetscScalar *arg1, PetscScalar *arg2, PetscInt n) {
  PetscFunctionBegin;
  while (n--) {
    *arg1 = MAX_FABS(*arg1, *arg2);
    arg1++;
    arg2++;
  }
  PetscFunctionReturn(0);
}

/*********************************ivec.c*************************************/
PetscErrorCode PCTFS_rvec_min(PetscScalar *arg1, PetscScalar *arg2, PetscInt n) {
  PetscFunctionBegin;
  while (n--) {
    *arg1 = PetscMin(*arg1, *arg2);
    arg1++;
    arg2++;
  }
  PetscFunctionReturn(0);
}

/*********************************ivec.c*************************************/
PetscErrorCode PCTFS_rvec_min_abs(PetscScalar *arg1, PetscScalar *arg2, PetscInt n) {
  PetscFunctionBegin;
  while (n--) {
    *arg1 = MIN_FABS(*arg1, *arg2);
    arg1++;
    arg2++;
  }
  PetscFunctionReturn(0);
}

/*********************************ivec.c*************************************/
PetscErrorCode PCTFS_rvec_exists(PetscScalar *arg1, PetscScalar *arg2, PetscInt n) {
  PetscFunctionBegin;
  while (n--) {
    *arg1 = EXISTS(*arg1, *arg2);
    arg1++;
    arg2++;
  }
  PetscFunctionReturn(0);
}

/***********************************ivec.c*************************************/
PetscErrorCode PCTFS_rvec_non_uniform(PetscScalar *arg1, PetscScalar *arg2, PetscInt n, PetscInt *arg3) {
  PetscInt i, j, type;

  PetscFunctionBegin;
  /* LATER: if we're really motivated we can sort and then unsort */
  for (i = 0; i < n;) {
    /* clump 'em for now */
    j    = i + 1;
    type = arg3[i];
    while ((j < n) && (arg3[j] == type)) j++;

    /* how many together */
    j -= i;

    /* call appropriate ivec function */
    if (type == GL_MAX) PCTFS_rvec_max(arg1, arg2, j);
    else if (type == GL_MIN) PCTFS_rvec_min(arg1, arg2, j);
    else if (type == GL_MULT) PCTFS_rvec_mult(arg1, arg2, j);
    else if (type == GL_ADD) PCTFS_rvec_add(arg1, arg2, j);
    else if (type == GL_MAX_ABS) PCTFS_rvec_max_abs(arg1, arg2, j);
    else if (type == GL_MIN_ABS) PCTFS_rvec_min_abs(arg1, arg2, j);
    else if (type == GL_EXISTS) PCTFS_rvec_exists(arg1, arg2, j);
    else SETERRQ(PETSC_COMM_SELF, PETSC_ERR_PLIB, "unrecognized type passed to PCTFS_rvec_non_uniform()!");

    arg1 += j;
    arg2 += j;
    i += j;
  }
  PetscFunctionReturn(0);
}

/***********************************ivec.c*************************************/
vfp PCTFS_rvec_fct_addr(PetscInt type) {
  if (type == NON_UNIFORM) return ((PetscErrorCode(*)(void *, void *, PetscInt, ...)) & PCTFS_rvec_non_uniform);
  else if (type == GL_MAX) return ((PetscErrorCode(*)(void *, void *, PetscInt, ...)) & PCTFS_rvec_max);
  else if (type == GL_MIN) return ((PetscErrorCode(*)(void *, void *, PetscInt, ...)) & PCTFS_rvec_min);
  else if (type == GL_MULT) return ((PetscErrorCode(*)(void *, void *, PetscInt, ...)) & PCTFS_rvec_mult);
  else if (type == GL_ADD) return ((PetscErrorCode(*)(void *, void *, PetscInt, ...)) & PCTFS_rvec_add);
  else if (type == GL_MAX_ABS) return ((PetscErrorCode(*)(void *, void *, PetscInt, ...)) & PCTFS_rvec_max_abs);
  else if (type == GL_MIN_ABS) return ((PetscErrorCode(*)(void *, void *, PetscInt, ...)) & PCTFS_rvec_min_abs);
  else if (type == GL_EXISTS) return ((PetscErrorCode(*)(void *, void *, PetscInt, ...)) & PCTFS_rvec_exists);

  /* catch all ... not good if we get here */
  return (NULL);
}