update docs to introduction of CloogScattering and CloogScatteringList

[cloog.git] / source / polylib / domain.c

   /**-------------------------------------------------------------------**
    **                               CLooG                               **
    **-------------------------------------------------------------------**
    **                             domain.c                              **
    **-------------------------------------------------------------------**
    **                   First version: october 28th 2001                **
    **-------------------------------------------------------------------**/


/******************************************************************************
 *               CLooG : the Chunky Loop Generator (experimental)             *
 ******************************************************************************
 *                                                                            *
 * Copyright (C) 2001-2005 Cedric Bastoul                                     *
 *                                                                            *
 * This is free software; you can redistribute it and/or modify it under the  *
 * terms of the GNU General Public License as published by the Free Software  *
 * Foundation; either version 2 of the License, or (at your option) any later *
 * version.                                                                   *
 *                                                                            *
 * This software is distributed in the hope that it will be useful, but       *
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY *
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License   *
 * for more details.                                                          *
 *                                                                            *
 * You should have received a copy of the GNU General Public License along    *
 * with software; if not, write to the Free Software Foundation, Inc.,        *
 * 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA                     *
 *                                                                            *
 * CLooG, the Chunky Loop Generator                                           *
 * Written by Cedric Bastoul, Cedric.Bastoul@inria.fr                         *
 *                                                                            *
 ******************************************************************************/
/* CAUTION: the english used for comments is probably the worst you ever read,
 *          please feel free to correct and improve it !
 */


# include <stdlib.h>
# include <stdio.h>
# include <ctype.h>
#include <cloog/polylib/cloog.h>


/**
 * The maximal number of rays allowed to be allocated by PolyLib. In fact since
 * version 5.20, PolyLib automatically tune the number of rays by multiplying
 * by 2 this number each time the maximum is reached. For unknown reasons
 * PolyLib makes a segmentation fault if this number is too small. If this
 * number is too small, performances will be reduced, if it is too high, memory
 * will be saturated. Note that the option "-rays X" set this number to X.
 */
int MAX_RAYS = 50 ;


/******************************************************************************
 *                             Memory leaks hunting                           *
 ******************************************************************************/


/**
 * These functions and global variables are devoted to memory leaks hunting: we
 * want to know at each moment how many Polyhedron structures had been allocated
 * (cloog_domain_allocated) and how many had been freed (cloog_domain_freed).
 * Each time a Polyhedron structure is allocated, a call to the function
 * cloog_domain_leak_up() must be carried out, and respectively
 * cloog_domain_leak_down() when a Polyhedron structure is freed. The special
 * variable cloog_domain_max gives the maximal number of Polyhedron structures
 * simultaneously alive (i.e. allocated and non-freed) in memory.
 * - July 3rd->11th 2003: first version (memory leaks hunt and correction).
 */


int cloog_domain_allocated = 0 ;
int cloog_domain_freed = 0 ;
int cloog_domain_max = 0 ;


static void cloog_domain_leak_up()
{ cloog_domain_allocated ++ ;
  if ((cloog_domain_allocated-cloog_domain_freed) > cloog_domain_max)
  cloog_domain_max = cloog_domain_allocated - cloog_domain_freed ;
}


static void cloog_domain_leak_down()
{ cloog_domain_freed ++ ;
}


/******************************************************************************
 *                              PolyLib interface                             *
 ******************************************************************************/


/* CLooG makes an intensive use of polyhedral operations and the PolyLib do
 * the job. Here are the interfaces to all the PolyLib calls (CLooG uses 19
 * PolyLib functions), with or without some adaptations. If another polyhedral
 * library can be used, only these functions have to be changed.
 * - April 16th 2005: Since PolyLib 5.20, compacting is no more useful and have
 *                    been removed. The direct use of the PolyLib's Polyhedron
 *                    data structure is also replaced with the CloogDomain data
 *                    structure that includes the Polyhedron and an additional
 *                    counter on how many pointers point on this structure.
 *                    This allows to save memory (cloog_domain_copy now only
 *                    increment the counter) while memory leaks are avoided (the
 *                    function cloog_domain_free decrements the counter and
 *                    actually frees the data structure only when its value
 *                    is 0).
 */

/**
 * Returns true if each scattering dimension is defined in terms
 * of the original iterators.
 */
int cloog_scattering_fully_specified(CloogScattering *scattering,
                                      CloogDomain *domain)
{
        int scattering_dim = cloog_domain_dimension(scattering) -
                                cloog_domain_dimension(domain);
        return scattering->polyhedron->NbEq >= scattering_dim;
}

/**
 * cloog_domain_matrix2domain function:
 * Given a matrix of constraints (matrix), this function constructs and returns
 * the corresponding domain (i.e. the CloogDomain structure including the
 * polyhedron with its double representation: constraint matrix and the set of
 * rays).
 */ 
CloogDomain * cloog_domain_matrix2domain(CloogMatrix * matrix)
{ return (cloog_domain_alloc(Constraints2Polyhedron(matrix,MAX_RAYS))) ;
}


/**
 * cloog_domain_domain2matrix function:
 * Given a polyhedron (in domain), this function returns its corresponding
 * matrix of constraints.
 */
CloogMatrix * cloog_domain_domain2matrix(CloogDomain * domain)
{
  return cloog_matrix_matrix(Polyhedron2Constraints(domain->polyhedron));
}

CloogConstraintSet *cloog_domain_constraints(CloogDomain *domain)
{
        return cloog_domain_domain2matrix(domain);
}


/**
 * cloog_domain_print function:
 * This function prints the content of a CloogDomain structure (domain) into
 * a file (foo, possibly stdout).
 */
void cloog_domain_print(FILE * foo, CloogDomain * domain)
{ Polyhedron_Print(foo,P_VALUE_FMT,domain->polyhedron) ;
  fprintf(foo,"Number of active references: %d\n",domain->references) ;
}

void cloog_domain_print_constraints(FILE *foo, CloogDomain *domain,
                                        int print_number)
{
  Polyhedron *polyhedron;
  CloogMatrix *matrix;

  if (print_number) {
    int j = 0;
    /* Number of polyhedron inside the union of disjoint polyhedra. */
    for (polyhedron = cloog_domain_polyhedron(domain); polyhedron;
                                                polyhedron = polyhedron->next)
      ++j;
    fprintf(foo, "%d\n", j);
  }

  /* The polyhedra themselves. */
  for (polyhedron = cloog_domain_polyhedron(domain); polyhedron;
                                              polyhedron = polyhedron->next) {
    matrix = cloog_matrix_matrix(Polyhedron2Constraints(polyhedron));
    cloog_matrix_print(foo,matrix);
    cloog_matrix_free(matrix);
  }
}

/**
 * cloog_polyhedron_print function:
 * This function prints the content of a Polyhedron structure (polyhedron) into
 * a file (foo, possibly stdout). Just there as a development facility.
 */
void cloog_polyhedron_print(FILE * foo, Polyhedron * polyhedron)
{ Polyhedron_Print(foo,P_VALUE_FMT,polyhedron) ;
}


/**
 * cloog_domain_free function:
 * This function frees the allocated memory for a CloogDomain structure
 * (domain). It decrements the number of active references to this structure,
 * if there are no more references on the structure, it frees it (with the
 * included list of polyhedra).
 */
void cloog_domain_free(CloogDomain * domain)
{ if (domain != NULL)
  { domain->references -- ;
    
    if (domain->references == 0)
    { if (domain->polyhedron != NULL)
      { cloog_domain_leak_down() ;
        Domain_Free(domain->polyhedron) ;
      }
      free(domain) ;
    }
  }
}

void cloog_scattering_free(CloogDomain * domain)
{
    cloog_domain_free(domain);
}


/**
 * cloog_domain_copy function:
 * This function returns a copy of a CloogDomain structure (domain). To save
 * memory this is not a memory copy but we increment a counter of active
 * references inside the structure, then return a pointer to that structure.
 */ 
CloogDomain * cloog_domain_copy(CloogDomain * domain)
{ domain->references ++ ;
  return domain ;
}


/**
 * cloog_domain_image function:
 * This function returns a CloogDomain structure such that the included
 * polyhedral domain is computed from the former one into another
 * domain according to a given affine mapping function (mapping). 
 */
CloogDomain * cloog_domain_image(CloogDomain * domain, CloogMatrix * mapping)
{ return (cloog_domain_alloc(DomainImage(domain->polyhedron,mapping,MAX_RAYS)));
}


/**
 * cloog_domain_preimage function:
 * Given a polyhedral domain (polyhedron) inside a CloogDomain structure and a
 * mapping function (mapping), this function returns a new CloogDomain structure
 * with a polyhedral domain which when transformed by mapping function (mapping)
 * gives (polyhedron).
 */
CloogDomain * cloog_domain_preimage(CloogDomain * domain, CloogMatrix * mapping)
{ return (cloog_domain_alloc(DomainPreimage(domain->polyhedron,
                                            mapping,MAX_RAYS))) ;
}


/**
 * cloog_domain_convex function:
 * Given a polyhedral domain (polyhedron), this function concatenates the lists
 * of rays and lines of the two (or more) polyhedra in the domain into one
 * combined list, and  find the set of constraints which tightly bound all of
 * those objects. It returns the corresponding polyhedron.
 */ 
CloogDomain * cloog_domain_convex(CloogDomain * domain)
{ return (cloog_domain_alloc(DomainConvex(domain->polyhedron,MAX_RAYS)));
}


/**
 * cloog_domain_simplified_hull:
 * Given a list (union) of polyhedra, this function returns a single
 * polyhedron that contains this union and uses only contraints that
 * appear in one or more of the polyhedra in the list.
 * 
 * We simply iterate over all constraints of all polyhedra and test
 * whether all rays of the other polyhedra satisfy/saturate the constraint.
 */
static CloogDomain *cloog_domain_simplified_hull(CloogDomain * domain)
{
  int dim = cloog_domain_dimension(domain);
  int i, j, k, l;
  int nb_pol = 0, nb_constraints = 0;
  Polyhedron *P;
  CloogMatrix **rays, *matrix;
  Value tmp;
  CloogDomain *bounds;

  value_init(tmp);
  for (P = domain->polyhedron; P; P = P->next) {
    ++nb_pol;
    nb_constraints += P->NbConstraints;
  }
  matrix = cloog_matrix_alloc(nb_constraints, 1 + dim + 1);
  nb_constraints = 0;
  rays = (CloogMatrix **)malloc(nb_pol * sizeof(CloogMatrix*));
  for (P = domain->polyhedron, i = 0; P; P = P->next, ++i)
    rays[i] = Polyhedron2Rays(P);

  for (P = domain->polyhedron, i = 0; P; P = P->next, ++i) {
    CloogMatrix *constraints = Polyhedron2Constraints(P);
    for (j = 0; j < constraints->NbRows; ++j) {
      for (k = 0; k < nb_pol; ++k) {
        if (i == k)
          continue;
        for (l = 0; l < rays[k]->NbRows; ++l) {
          Inner_Product(constraints->p[j]+1, rays[k]->p[l]+1, dim+1, &tmp);
          if (value_neg_p(tmp))
            break;
          if ((value_zero_p(constraints->p[j][0]) || 
               value_zero_p(rays[k]->p[l][0])) && value_pos_p(tmp))
            break;
        }
        if (l < rays[k]->NbRows)
          break;
      }
      if (k == nb_pol)
        Vector_Copy(constraints->p[j], matrix->p[nb_constraints++], 1+dim+1);
    }
    Matrix_Free(constraints);
  }

  for (P = domain->polyhedron, i = 0; P; P = P->next, ++i)
    Matrix_Free(rays[i]);
  free(rays);
  value_clear(tmp);

  matrix->NbRows = nb_constraints;
  bounds = cloog_domain_matrix2domain(matrix);
  cloog_matrix_free(matrix);

  return bounds;
}


/**
 * cloog_domain_simple_convex:
 * Given a list (union) of polyhedra, this function returns a "simple"
 * convex hull of this union.  In particular, the constraints of the
 * the returned polyhedron consist of (parametric) lower and upper
 * bounds on individual variables and constraints that appear in the
 * original polyhedra.
 *
 * nb_par is the number of parameters of the domain.
 */
CloogDomain * cloog_domain_simple_convex(CloogDomain * domain, int nb_par)
{
  int i;
  int dim = cloog_domain_dimension(domain) - nb_par;
  CloogDomain *convex = NULL;

  if (cloog_domain_isconvex(domain))
    return cloog_domain_copy(domain);

  for (i = 0; i < dim; ++i) {
    CloogDomain *bounds = cloog_domain_bounds(domain, i, nb_par);

    if (!convex)
      convex = bounds;
    else {
      CloogDomain *temp = cloog_domain_intersection(convex, bounds);
      cloog_domain_free(bounds);
      cloog_domain_free(convex);
      convex = temp;
    }
  }
  if (dim > 1) {
    CloogDomain *temp, *bounds;

    bounds = cloog_domain_simplified_hull(domain);
    temp = cloog_domain_intersection(convex, bounds);
    cloog_domain_free(bounds);
    cloog_domain_free(convex);
    convex = temp;
  }

  return convex;
}


/**
 * cloog_domain_simplify function:
 * Given two polyhedral domains (pol1) and (pol2) inside two CloogDomain
 * structures, this function finds the largest domain set (or the smallest list
 * of non-redundant constraints), that when intersected with polyhedral
 * domain (pol2) equals (Pol1)intersect(Pol2). The output is a new CloogDomain
 * structure with a polyhedral domain with the "redundant" constraints removed.
 * NB: this function do not work as expected with unions of polyhedra...
 */ 
CloogDomain * cloog_domain_simplify(CloogDomain * dom1, CloogDomain * dom2)
{
  CloogMatrix *M, *M2;
  CloogDomain *dom;
  Polyhedron *P = dom1->polyhedron;

  /* DomainSimplify doesn't remove all redundant equalities,
   * so we remove them here first in case both dom1 and dom2
   * are single polyhedra (i.e., not unions of polyhedra).
   */
  if (!dom1->polyhedron->next && !dom2->polyhedron->next &&
      P->NbEq && dom2->polyhedron->NbEq) {
    int i, row;
    int rows = P->NbEq + dom2->polyhedron->NbEq;
    int cols = P->Dimension+2;
    int rank;
    M = cloog_matrix_alloc(rows, cols);
    M2 = cloog_matrix_alloc(P->NbConstraints, cols);
    Vector_Copy(dom2->polyhedron->Constraint[0], M->p[0], 
                dom2->polyhedron->NbEq * cols);
    rank = dom2->polyhedron->NbEq;
    row = 0;
    for (i = 0; i < P->NbEq; ++i) {
      Vector_Copy(P->Constraint[i], M->p[rank], cols);
      if (Gauss(M, rank+1, cols-1) > rank) {
        Vector_Copy(P->Constraint[i], M2->p[row++], cols);
        rank++;
      }
    }
    if (row < P->NbEq) {
      if (P->NbConstraints > P->NbEq)
        Vector_Copy(P->Constraint[P->NbEq], M2->p[row], 
                    (P->NbConstraints - P->NbEq) * cols);
      P = Constraints2Polyhedron(M2, MAX_RAYS);
    }
    cloog_matrix_free(M2);
    cloog_matrix_free(M);
  }
  dom = cloog_domain_alloc(DomainSimplify(P, dom2->polyhedron,MAX_RAYS));
  if (P != dom1->polyhedron)
    Polyhedron_Free(P);
  return dom;
}


/**
 * cloog_domain_union function:
 * This function returns a new CloogDomain structure including a polyhedral
 * domain which is the union of two polyhedral domains (pol1) U (pol2) inside
 * two CloogDomain structures.
 */
CloogDomain * cloog_domain_union(CloogDomain * dom1, CloogDomain * dom2)
{ return (cloog_domain_alloc(DomainUnion(dom1->polyhedron,
                                         dom2->polyhedron,MAX_RAYS))) ;
}


/**
 * cloog_domain_intersection function:
 * This function returns a new CloogDomain structure including a polyhedral
 * domain which is the intersection of two polyhedral domains (pol1)inter(pol2)
 * inside two CloogDomain structures.
 */ 
CloogDomain * cloog_domain_intersection(CloogDomain * dom1, CloogDomain * dom2)
{ return (cloog_domain_alloc(DomainIntersection(dom1->polyhedron,
                                                dom2->polyhedron,MAX_RAYS))) ;
}


/**
 * cloog_domain_difference function:
 * This function returns a new CloogDomain structure including a polyhedral
 * domain which is the difference of two polyhedral domains domain \ minus
 * inside two CloogDomain structures.
 * - November 8th 2001: first version.
 */ 
CloogDomain * cloog_domain_difference(CloogDomain * domain, CloogDomain * minus)
{ if (cloog_domain_isempty(minus))
  return(cloog_domain_copy(domain)) ;
  else
  return (cloog_domain_alloc(DomainDifference(domain->polyhedron,
                                              minus->polyhedron,MAX_RAYS))) ;
}


/**
 * cloog_domain_addconstraints function :
 * This function adds source's polyhedron constraints to target polyhedron: for
 * each element of the polyhedron inside 'target' (i.e. element of the union
 * of polyhedra) it adds the constraints of the corresponding element in
 * 'source'.
 * - August 10th 2002: first version.
 * Nota bene for future : it is possible that source and target don't have the
 * same number of elements (try iftest2 without non-shared constraint
 * elimination in cloog_loop_separate !). This function is yet another part
 * of the DomainSimplify patching problem...
 */
CloogDomain * cloog_domain_addconstraints(domain_source, domain_target)
CloogDomain * domain_source, * domain_target ;
{ unsigned nb_constraint ;
  Value * constraints ;
  Polyhedron * source, * target, * new, * next, * last ;

  source = domain_source->polyhedron ;
  target = domain_target->polyhedron ;
  
  constraints = source->p_Init ;
  nb_constraint = source->NbConstraints ;
  source = source->next ;
  new = AddConstraints(constraints,nb_constraint,target,MAX_RAYS) ;
  last = new ;
  next = target->next ;

  while (next != NULL)
  { /* BUG !!! This is actually a bug. I don't know yet how to cleanly avoid
     * the situation where source and target do not have the same number of
     * elements. So this 'if' is an awful trick, waiting for better.
     */
    if (source != NULL)
    { constraints = source->p_Init ;
      nb_constraint = source->NbConstraints ;
      source = source->next ;
    }
    last->next = AddConstraints(constraints,nb_constraint,next,MAX_RAYS) ;
    last = last->next ;
    next = next->next ;
  }

  return (cloog_domain_alloc(new)) ;
}


/**
 * cloog_domain_sort function:
 * This function topologically sorts (nb_pols) polyhedra. Here (pols) is a an
 * array of pointers to polyhedra, (nb_pols) is the number of polyhedra,
 * (level) is the level to consider for partial ordering (nb_par) is the
 * parameter space dimension, (permut) if not NULL, is an array of (nb_pols)
 * integers that contains a permutation specification after call in order to
 * apply the topological sorting. 
 */
void cloog_domain_sort(CloogDomain **doms, unsigned nb_doms, unsigned level,
                        unsigned nb_par, int *permut)
{
  int i, *time;
  Polyhedron **pols = (Polyhedron **) malloc(nb_doms * sizeof(Polyhedron *));

  for (i = 0; i < nb_doms; i++)
    pols[i] = cloog_domain_polyhedron(doms[i]);
  
  /* time is an array of (nb_doms) integers to store logical time values. We
   * do not use it, but it is compulsory for PolyhedronTSort.
   */
  time = (int *)malloc(nb_doms * sizeof(int));

  /* PolyhedronTSort will fill up permut (and time). */
  PolyhedronTSort(pols, nb_doms, level, nb_par, time, permut, MAX_RAYS);
    
  free(pols);
  free(time) ;
}


/**
 * cloog_domain_empty function:
 * This function allocates the memory space for a CloogDomain structure and
 * sets its polyhedron to an empty polyhedron with the same dimensions
 * as template
 * Then it returns a pointer to the allocated space.
 * - June 10th 2005: first version.
 */
CloogDomain * cloog_domain_empty(CloogDomain *template)
{ return cloog_domain_alloc(Empty_Polyhedron(cloog_domain_dimension(template))) ;
}


/******************************************************************************
 *                          Structure display function                        *
 ******************************************************************************/


static void print_structure_prefix(FILE *file, int level)
{
  int i;

  for(i = 0; i < level; i++)
    fprintf(file, "|\t");
}


/**
 * cloog_domain_print_structure :
 * this function is a more human-friendly way to display the CloogDomain data
 * structure, it only shows the constraint system and includes an indentation
 * level (level) in order to work with others print_structure functions.
 * Written by Olivier Chorier, Luc Marchaud, Pierre Martin and Romain Tartiere.
 * - April 24th 2005: Initial version.
 * - May   26th 2005: Memory leak hunt.
 * - June  16th 2005: (Ced) Integration in domain.c.
 */
void cloog_domain_print_structure(FILE *file, CloogDomain *domain, int level,
                                  const char *name)
{
  Polyhedron *P;
  CloogMatrix * matrix ;

  print_structure_prefix(file, level);
  
  if (domain != NULL)
  { fprintf(file,"+-- %s\n", name);
  
    /* Print the matrix. */
    for (P = domain->polyhedron; P; P = P->next) {
      matrix = Polyhedron2Constraints(P);
      cloog_matrix_print_structure(file, matrix, level);
      cloog_matrix_free(matrix);

      /* A blank line. */
      print_structure_prefix(file, level+1);
      fprintf(file,"\n");
    }
  }
  else
  fprintf(file,"+-- Null CloogDomain\n") ;

}


/**
 * cloog_scattering_list_print function:
 * This function prints the content of a CloogScatteringList structure into a
 * file (foo, possibly stdout).
 * - November 6th 2001: first version.
 */
void cloog_scattering_list_print(FILE * foo, CloogScatteringList * list)
{ while (list != NULL)
  { cloog_domain_print(foo, list->scatt);
    list = list->next ;
  }
}


/******************************************************************************
 *                         Memory deallocation function                       *
 ******************************************************************************/


/**
 * cloog_scattering_list_free function:
 * This function frees the allocated memory for a CloogScatteringList structure.
 * - November 6th 2001: first version.
 */
void cloog_scattering_list_free(CloogScatteringList * list)
{ CloogScatteringList * temp ;
  
  while (list != NULL)
  { temp = list->next ;
    cloog_scattering_free(list->scatt);
    free(list) ;
    list = temp ;
  }
}


/******************************************************************************
 *                               Reading function                             *
 ******************************************************************************/


/**
 * cloog_domain_read function:
 * Adaptation from the PolyLib. This function reads a matrix into a file (foo,
 * posibly stdin) and returns a pointer to a polyhedron containing the read
 * information. 
 * - October 18th 2001: first version.
 */
CloogDomain * cloog_domain_read(FILE * foo, int nb_parameters,
                                CloogOptions *options)
{ CloogMatrix * matrix ;
  CloogDomain * domain ;
  
  matrix = cloog_matrix_read(foo) ;
  domain = cloog_domain_matrix2domain(matrix) ;
  cloog_matrix_free(matrix) ;
  
  return(domain) ;
}


/**
 * cloog_domain_read_context:
 * Read parameter domain.  For the PolyLib backend, a parameter domain
 * is indistinguishable from a parametric domain.
 */
CloogDomain *cloog_domain_read_context(FILE * foo, CloogOptions *options)
{
  return cloog_domain_read(foo, 0, options);
}


/**
 * cloog_domain_from_context
 * Reinterpret context by turning parameters into variables.
 * For the PolyLib backend, this has no effect.
 */
CloogDomain *cloog_domain_from_context(CloogDomain *context)
{
  return context;
}


/**
 * cloog_domain_union_read function:
 * This function reads a union of polyhedra into a file (foo, posibly stdin) and
 * returns a pointer to a Polyhedron containing the read information. 
 * - September 9th 2002: first version.
 * - October  29th 2005: (debug) removal of a leak counting "correction" that
 *                       was just false since ages.
 */
CloogDomain * cloog_domain_union_read(FILE * foo, int nb_parameters,
                                        CloogOptions *options)
{ int i, nb_components ;
  char s[MAX_STRING] ;
  CloogDomain * domain, * temp, * old ;

  /* domain reading: nb_components (constraint matrices). */
  while (fgets(s,MAX_STRING,foo) == 0) ;
  while ((*s=='#' || *s=='\n') || (sscanf(s," %d",&nb_components)<1))
  fgets(s,MAX_STRING,foo) ;
  
  if (nb_components > 0)
  { /* 1. first part of the polyhedra union, */
    domain = cloog_domain_read(foo, nb_parameters, options);
    /* 2. and the nexts. */
    for (i=1;i<nb_components;i++)
    { /* Leak counting is OK since next allocated domain is freed here. */
      temp = cloog_domain_read(foo, nb_parameters, options);
      old = domain ;
      domain = cloog_domain_union(temp,old) ;
      cloog_domain_free(temp) ;
      cloog_domain_free(old) ;
    }    
    return domain ;
  }
  else
  return NULL ;
}


/**
 * cloog_scattering_read function:
 * This function reads in a scattering function fro the file foo.
 */
CloogScattering *cloog_scattering_read(FILE *foo,
                                    CloogDomain *domain, CloogOptions *options)
{
    /* The PolyLib backend doesn't need to know the number of parameters. */
    return cloog_domain_read(foo, -1, options);
}


/******************************************************************************
 *                            Processing functions                            *
 ******************************************************************************/


/**
 * cloog_domain_malloc function:
 * This function allocates the memory space for a CloogDomain structure and
 * sets its fields with default values. Then it returns a pointer to the
 * allocated space.
 * - November 21th 2005: first version.
 */
CloogDomain * cloog_domain_malloc()
{ CloogDomain * domain ;
  
  domain = (CloogDomain *)malloc(sizeof(CloogDomain)) ;
  if (domain == NULL) 
    cloog_die("memory overflow.\n");
  cloog_domain_leak_up() ;
  
  /* We set the various fields with default values. */
  domain->polyhedron = NULL ;
  domain->references = 1 ;
  
  return domain ;
}


/**
 * cloog_domain_alloc function:
 * This function allocates the memory space for a CloogDomain structure and
 * sets its fields with those given as input. Then it returns a pointer to the
 * allocated space.
 * - April    19th 2005: first version.
 * - November 21th 2005: cloog_domain_malloc use.
 */
CloogDomain * cloog_domain_alloc(Polyhedron * polyhedron)
{ CloogDomain * domain ;
  
  if (polyhedron == NULL)
  return NULL ;
  else
  { domain = cloog_domain_malloc() ;
    domain->polyhedron = polyhedron ;
    
    return domain ;
  }
}


/**
 * cloog_domain_isempty function:
 * This function returns 1 if the polyhedron given as input is empty, 0
 * otherwise.
 * - October 28th 2001: first version.
 */ 
int cloog_domain_isempty(CloogDomain * domain)
{ if (!domain || domain->polyhedron == NULL)
  return 1 ;

  if (domain->polyhedron->next)
  return(0) ;
  return((domain->polyhedron->Dimension < domain->polyhedron->NbEq) ? 1 : 0) ;
}


/**
 * cloog_domain_universe function:
 * This function returns the complete dim-dimensional space.
 */
CloogDomain *cloog_domain_universe(unsigned dim, CloogOptions *options)
{
  return cloog_domain_alloc(Universe_Polyhedron(dim));
}


/**
 * cloog_domain_project function:
 * From Quillere's LoopGen 0.4. This function returns the projection of
 * (domain) on the (level) first dimensions (i.e. outer loops). It returns a
 * pointer to the projected Polyhedron.
 * - nb_par is the number of parameters.
 **
 * - October 27th 2001: first version.
 * - June 21rd 2005: Adaptation for GMP (based on S. Verdoolaege's version of
 *                   CLooG 0.12.1).
 */ 
CloogDomain * cloog_domain_project(CloogDomain * domain, int level, int nb_par)
{ int row, column, nb_rows, nb_columns, difference ;
  CloogDomain * projected_domain ;
  CloogMatrix * matrix ;

  nb_rows = level + nb_par + 1 ;
  nb_columns = domain->polyhedron->Dimension + 1 ;
  difference = nb_columns - nb_rows ;
  
  if (difference == 0)
  return(cloog_domain_copy(domain)) ;
  
  matrix = cloog_matrix_alloc(nb_rows,nb_columns) ;
     
  for (row=0;row<level;row++)
  for (column=0;column<nb_columns; column++)
  value_set_si(matrix->p[row][column],(row == column ? 1 : 0)) ;

  for (;row<nb_rows;row++)
  for (column=0;column<nb_columns;column++)
  value_set_si(matrix->p[row][column],(row+difference == column ? 1 : 0)) ;
  
  projected_domain = cloog_domain_image(domain,matrix) ;
  cloog_matrix_free(matrix) ;

  return(projected_domain) ;
}  


/**
 * cloog_domain_bounds:
 * Given a list (union) of polyhedra "domain", this function returns a single
 * polyhedron with constraints that reflect the (parametric) lower and
 * upper bound on dimension "dim".
 *
 * nb_par is the number of parameters of the domain.
 */
CloogDomain * cloog_domain_bounds(CloogDomain * domain, int dim, int nb_par)
{
  int row, nb_rows, nb_columns, difference;
  CloogDomain * projected_domain, *extended_domain, *bounds;
  CloogMatrix * matrix ;

  nb_rows = 1 + nb_par + 1;
  nb_columns = domain->polyhedron->Dimension + 1 ;
  difference = nb_columns - nb_rows ;
  
  if (difference == 0)
    return(cloog_domain_convex(domain));
  
  matrix = cloog_matrix_alloc(nb_rows, nb_columns);
     
  value_set_si(matrix->p[0][dim], 1);
  for (row = 1; row < nb_rows; row++)
    value_set_si(matrix->p[row][row+difference], 1);
  
  projected_domain = cloog_domain_image(domain,matrix) ;
  extended_domain = cloog_domain_preimage(projected_domain, matrix);
  cloog_domain_free(projected_domain);
  cloog_matrix_free(matrix) ;
  bounds = cloog_domain_convex(extended_domain);
  cloog_domain_free(extended_domain);

  return bounds;
}  


/**
 * cloog_domain_extend function:
 * From Quillere's LoopGen 0.4. This function returns the (domain) given as
 * input with (dim)+(nb_par) dimensions. The new dimensions are added before
 * the (nb_par) parameters. This function does not free (domain), and returns
 * a new polyhedron.
 * - nb_par is the number of parameters.
 **
 * - October 27th 2001: first version.
 * - June 21rd 2005: Adaptation for GMP (based on S. Verdoolaege's version of
 *                 CLooG 0.12.1).
 */ 
CloogDomain * cloog_domain_extend(CloogDomain * domain, int dim, int nb_par)
{ int row, column, nb_rows, nb_columns, difference ;
  CloogDomain * extended_domain ;
  CloogMatrix * matrix ;
  
  nb_rows = 1 + domain->polyhedron->Dimension ;
  nb_columns = dim + nb_par + 1 ;
  difference = nb_columns - nb_rows ;
  
  if (difference == 0)
  return(cloog_domain_copy(domain)) ;
  
  matrix = cloog_matrix_alloc(nb_rows,nb_columns) ;
    
  for (row=0;row<domain->polyhedron->Dimension-nb_par;row++)
  for (column=0;column<nb_columns;column++)
  value_set_si(matrix->p[row][column],(row == column ? 1 : 0)) ;
  
  for (;row<=domain->polyhedron->Dimension;row++)
  for (column=0;column<nb_columns;column++)
  value_set_si(matrix->p[row][column],(row+difference == column ? 1 : 0)) ;
  
  extended_domain = cloog_domain_preimage(domain,matrix) ;
  cloog_matrix_free(matrix) ;

  return(extended_domain) ;
}


/**
 * cloog_domain_never_integral function:
 * For us, an equality like 3*i -4 = 0 is always false since 4%3 != 0. This
 * function returns a boolean set to 1 if there is this kind of 'never true'
 * constraint inside a polyhedron, 0 otherwise.
 * - domain is the polyhedron to check,
 **
 * - November 28th 2001: first version. 
 * - June 26th 2003: for iterators, more 'never true' constraints are found
 *                   (compare cholesky2 and vivien with a previous version),
 *                   checking for the parameters created (compare using vivien).
 * - June 28th 2003: Previously in loop.c and called
 *                   cloog_loop_simplify_nevertrue, now here !
 * - June 21rd 2005: Adaptation for GMP (based on S. Verdoolaege's version of
 *                   CLooG 0.12.1).
 * - October 14th 2005: Complete rewriting, not faster but code quite shorter.
 */
int cloog_domain_never_integral(CloogDomain * domain)
{ int i, dimension ;
  Value gcd, modulo ;
  Polyhedron * polyhedron ;

  if ((domain == NULL) || (domain->polyhedron == NULL))
  return 1 ;
  
  value_init_c(gcd) ;
  value_init_c(modulo) ;
  polyhedron = domain->polyhedron ;
  dimension = polyhedron->Dimension + 2  ;
  
  /* For each constraint... */
  for (i=0; i<polyhedron->NbConstraints; i++)  
  { /* If we have an equality and the scalar part is not zero... */
    if (value_zero_p(polyhedron->Constraint[i][0]) && 
        value_notzero_p(polyhedron->Constraint[i][dimension-1]))
    { /* Then we check whether the scalar can be divided by the gcd of the
       * unknown vector (including iterators and parameters) or not. If not,
       * there is no integer point in the polyhedron and we return 1.
       */
      Vector_Gcd(&(polyhedron->Constraint[i][1]),dimension-2,&gcd) ;
      value_modulus(modulo,polyhedron->Constraint[i][dimension-1],gcd) ;
      
      if (value_notzero_p(modulo))
      { value_clear_c(gcd) ;
        value_clear_c(modulo) ;
        return 1 ;
      }
    }
  }
  
  value_clear_c(gcd) ;
  value_clear_c(modulo) ;
  return(0) ;
}


/**
 * cloog_domain_stride function:
 * This function finds the stride imposed to unknown with the column number
 * 'strided_level' in order to be integral. For instance, if we have a
 * constraint like -i - 2j + 2k = 0, and we consider k, then k can be integral
 * only if (i + 2j)%2 = 0. Then only if i%2 = 0. Then k imposes a stride 2 to
 * the unknown i. The function returns the imposed stride in a parameter field.
 * - domain is the set of constraint we have to consider,
 * - strided_level is the column number of the unknown for which a stride have
 *   to be found,
 * - looking_level is the column number of the unknown that impose a stride to
 *   the first unknown.
 * - stride is the stride that is returned back as a function parameter. 
 * - offset is the value of the constant c if the condition is of the shape
 *   (i + c)%s = 0, s being the stride.
 **
 * - June 28th 2003: first version.
 * - July 14th 2003: can now look for multiple striding constraints and returns
 *                   the GCD of the strides and the common offset.
 * - June 21rd 2005: Adaptation for GMP (based on S. Verdoolaege's version of
 *                   CLooG 0.12.1).
 */
void cloog_domain_stride(domain, strided_level, nb_par, stride, offset)
CloogDomain * domain ;
int strided_level, nb_par ;
Value  * stride, * offset;
{ int i, dimension;
  Polyhedron * polyhedron ;
  int n_col, n_row, rank;
  CloogMatrix *M;
  Matrix *U;
  Vector *V;

  polyhedron = domain->polyhedron ;
  dimension = polyhedron->Dimension ;

  /* Look at all equalities involving strided_level and the inner
   * iterators.  We can ignore the outer iterators and the parameters
   * here because the lower bound on strided_level is assumed to
   * be a constant.
   */
  n_col = (1+dimension-nb_par) - strided_level;
  for (i=0, n_row=0; i < polyhedron->NbEq; i++)
    if (First_Non_Zero(polyhedron->Constraint[i]+strided_level, n_col) != -1)
      ++n_row;

  M = cloog_matrix_alloc(n_row+1, n_col+1);
  for (i=0, n_row = 0; i < polyhedron->NbEq; i++) {
    if (First_Non_Zero(polyhedron->Constraint[i]+strided_level, n_col) == -1)
      continue;
    Vector_Copy(polyhedron->Constraint[i]+strided_level, M->p[n_row], n_col);
    value_assign(M->p[n_row][n_col], polyhedron->Constraint[i][1+dimension]);
    ++n_row;
  }
  value_set_si(M->p[n_row][n_col], 1);

  /* Then look at the general solution to the above equalities. */
  rank = SolveDiophantine(M, &U, &V);
  cloog_matrix_free(M);

  if (rank == -1) {
    /* There is no solution, so the body of this loop will
     * never execute.  We just leave the constraints alone here so
     * that they will ensure the body will not be executed.
     * We should probably propagate this information up so that
     * the loop can be removed entirely.
     */ 
    value_set_si(*offset, 0);
    value_set_si(*stride, 1);
  } else {
    /* Compute the gcd of the coefficients defining strided_level. */
    Vector_Gcd(U->p[0], U->NbColumns, stride);
    value_oppose(*offset, V->p[0]);
    value_pmodulus(*offset, *offset, *stride);
  }
  Matrix_Free(U);
  Vector_Free(V);

  return ;
}


/**
 * cloog_domain_integral_lowerbound function:
 * This function returns 1 if the lower bound of an iterator (such as its
 * column rank in the constraint set 'domain' is 'level') is integral,
 * 0 otherwise. If the lower bound is actually integral, the function fills
 * the 'lower' field with the lower bound value.
 * - June 29th 2003: first version.
 * - June 21rd 2005: Adaptation for GMP (based on S. Verdoolaege's version of
 *                   CLooG 0.12.1).
 */
int cloog_domain_integral_lowerbound(domain, level, lower)
CloogDomain * domain ;
int level ;
Value * lower ;
{ int i, first_lower=1, dimension, lower_constraint=-1 ;
  Value iterator, constant, tmp;
  Polyhedron * polyhedron ;
 
  polyhedron = domain->polyhedron ;
  dimension = polyhedron->Dimension ;
  
  /* We want one and only one lower bound (e.g. no equality, no maximum
   * calculation...).
   */
  for (i=0; i<polyhedron->NbConstraints; i++)  
  if (value_zero_p(polyhedron->Constraint[i][0]) && 
      value_notzero_p(polyhedron->Constraint[i][level]))
  return 0 ;

  for (i=0; i<polyhedron->NbConstraints; i++)  
  if (value_pos_p(polyhedron->Constraint[i][level]))
  { if (first_lower)
    { first_lower = 0 ;
      lower_constraint = i ;
    }
    else
    return 0 ;
  }
  if (first_lower)
  return 0 ;
  
  /* We want an integral lower bound: no other non-zero entry except the
   * iterator coefficient and the constant.
   */
  for (i=1; i<level; i++)  
  if (value_notzero_p(polyhedron->Constraint[lower_constraint][i]))
  return 0 ;
  for (i=level+1; i<=polyhedron->Dimension; i++)  
  if (value_notzero_p(polyhedron->Constraint[lower_constraint][i]))
  return 0 ;

  value_init_c(iterator) ;
  value_init_c(constant) ;
  value_init_c(tmp) ;

  /* If all is passed, then find the lower bound and return 1. */
  value_assign(iterator, polyhedron->Constraint[lower_constraint][level]) ;
  value_oppose(constant, polyhedron->Constraint[lower_constraint][dimension+1]);

  value_modulus(tmp, constant, iterator) ;
  value_division(*lower, constant, iterator) ;

  if (!(value_zero_p(tmp) || value_neg_p(constant)))
  value_increment(*lower, *lower) ;
  
  value_clear_c(iterator) ;
  value_clear_c(constant) ;
  value_clear_c(tmp) ;

  return 1 ;
}


/**
 * cloog_domain_lowerbound_update function:
 * This function updates the integral lower bound of an iterator (such as its
 * column rank in the constraint set 'domain' is 'level') into  'lower'
 * and returns the updated domain.
 * - Jun  29th 2003: first version.
 * - June 21rd 2005: Adaptation for GMP (based on S. Verdoolaege's version of
 *                   CLooG 0.12.1).
 */
CloogDomain *cloog_domain_lowerbound_update(CloogDomain *domain, int level,
                                                cloog_int_t lower)
{ int i ;
  Polyhedron * polyhedron ;
 
  polyhedron = domain->polyhedron ;
 
  /* There is only one lower bound, the first one is the good one. */
  for (i=0; i<polyhedron->NbConstraints; i++)  
  if (value_pos_p(polyhedron->Constraint[i][level]))
  { value_set_si(polyhedron->Constraint[i][level], 1) ;
    value_oppose(polyhedron->Constraint[i][polyhedron->Dimension+1], lower) ;
    break ;
  }
  return domain;
}


/**
 * cloog_domain_lazy_equal function:
 * This function returns 1 if the domains given as input are the same, 0 if it
 * is unable to decide. This function makes an entry-to-entry comparison between
 * the constraint systems, if all the entries are the same, the domains are
 * obviously the same and it returns 1, at the first difference, it returns 0.
 * This is a very fast way to verify this property. It has been shown (with the
 * CLooG benchmarks) that operations on equal domains are 17% of all the
 * polyhedral computations. For 75% of the actually identical domains, this
 * function answer that they are the same and allow to give immediately the
 * trivial solution instead of calling the heavy general functions of PolyLib.
 * - August 22th 2003: first version.
 * - June 21rd 2005: Adaptation for GMP (based on S. Verdoolaege's version of
 *                   CLooG 0.12.1).
 */
int cloog_domain_lazy_equal(CloogDomain * d1, CloogDomain * d2)
{ int i, nb_elements ;
  Polyhedron * p1, * p2 ;
 
  p1 = d1->polyhedron ;
  p2 = d2->polyhedron ;

  while ((p1 != NULL) && (p2 != NULL))
  { if ((p1->NbConstraints != p2->NbConstraints) ||
        (p1->Dimension != p2->Dimension))
    return 0 ;
  
    nb_elements = p1->NbConstraints * (p1->Dimension + 2) ;
  
    for (i=0;i<nb_elements;i++)
    if (value_ne(p1->p_Init[i], p2->p_Init[i]))
    return 0 ;
    
    p1 = p1->next ;
    p2 = p2->next ;
  }
  
  if ((p1 != NULL) || (p2 != NULL))
  return 0 ;
  
  return 1 ;
}


/**
 * cloog_scattering_lazy_block function:
 * This function returns 1 if the two domains d1 and d2 given as input are the
 * same (possibly except for a dimension equal to a constant where we accept
 * a difference of 1) AND if we are sure that there are no other domain in
 * the code generation problem that may put integral points between those of
 * d1 and d2 (0 otherwise). In fact this function answers the question "can I
 * safely consider the two domains as only one with two statements (a block) ?".
 * The original implementation had a problem and has therefore been
 * (temporarily) replaced by the safest possible implementation: always
 * assume that we cannot block the two statements.
 * - d1 and d2 are the two domains to check for blocking,
 * - scattering is the linked list of all domains,
 * - scattdims is the total number of scattering dimentions.
 */
int cloog_scattering_lazy_block(CloogScattering *d1, CloogScattering *d2,
                            CloogScatteringList *scattering, int scattdims)
{
  return 0;
}


/**
 * cloog_domain_lazy_disjoint function:
 * This function returns 1 if the domains given as input are disjoint, 0 if it
 * is unable to decide. This function finds the unknown with fixed values in
 * both domains (on a given constraint, their column entry is not zero and
 * only the constant coefficient can be different from zero) and verify that
 * their values are the same. If not, the domains are obviously disjoint and
 * it returns 1, if there is not such case it returns 0.  This is a very fast
 * way to verify this property. It has been shown (with the CLooG benchmarks)
 * that operations on disjoint domains are 36% of all the polyhedral
 * computations. For 94% of the actually identical domains, this
 * function answer that they are disjoint and allow to give immediately the
 * trivial solution instead of calling the heavy general functions of PolyLib.
 * - August 22th 2003: first version.
 * - June   21rd 2005: Adaptation for GMP (based on S. Verdoolaege's version of
 *                     CLooG 0.12.1).
 */
int cloog_domain_lazy_disjoint(CloogDomain * d1, CloogDomain * d2)
{ int i1, j1, i2, j2, scat_dim ;
  Value scat_val ;
  Polyhedron * p1, * p2 ;
 
  p1 = d1->polyhedron ;
  p2 = d2->polyhedron ;

  if ((p1->next != NULL) || (p2->next != NULL))
  return 0 ;
  
  value_init_c(scat_val) ;
  
  for (i1=0; i1<p1->NbConstraints; i1++)
  { if (value_notzero_p(p1->Constraint[i1][0]))
    continue ;
    
    scat_dim = 1 ;
    while (value_zero_p(p1->Constraint[i1][scat_dim]) &&
           (scat_dim < p1->Dimension))
    scat_dim ++ ;
    
    if (value_notone_p(p1->Constraint[i1][scat_dim]))
    continue ;
    else
    { for (j1=scat_dim+1; j1<=p1->Dimension; j1++)
      if (value_notzero_p(p1->Constraint[i1][j1]))
      break ;
      
      if (j1 != p1->Dimension+1)
      continue ;
      
      value_assign(scat_val,p1->Constraint[i1][p1->Dimension+1]) ;
            
      for (i2=0; i2<p2->NbConstraints; i2++)
      { for (j2=0;j2<scat_dim;j2++)
        if (value_notzero_p(p2->Constraint[i2][j2]))
        break ;
       
        if ((j2 != scat_dim) || value_notone_p(p2->Constraint[i2][scat_dim]))
        continue ;
       
        for (j2=scat_dim+1; j2<=p2->Dimension; j2++)
        if (value_notzero_p(p2->Constraint[i2][j2]))
        break ;
       
        if (j2 != p2->Dimension+1)
        continue ;
       
        if (value_ne(p2->Constraint[i2][p2->Dimension+1],scat_val)) 
        { value_clear_c(scat_val) ;
          return 1 ;
        }
      }
    }
  }

  value_clear_c(scat_val) ;
  return 0 ;
} 
 
 
/**
 * cloog_scattering_list_lazy_same function:
 * This function returns 1 if two domains in the list are the same, 0 if it
 * is unable to decide.
 * - February 9th 2004: first version.
 */
int cloog_scattering_list_lazy_same(CloogScatteringList * list)
{ /*int i=1, j=1 ;*/
  CloogScatteringList * current, * next ;

  current = list ;
  while (current != NULL)
  { next = current->next ;
    /*j=i+1;*/
    while (next != NULL)
    { if (cloog_domain_lazy_equal(current->scatt, next->scatt))
      { /*printf("Same domains: %d and %d\n",i,j) ;*/
        return 1 ;
      }
      /*j++ ;*/
      next = next->next ;
    }
    /*i++ ;*/
    current = current->next ;
  }
  
  return 0 ;
}


/**
 * Those functions are provided for "object encapsulation", to separate as much
 * as possible the inside of the CloogDomain structure from the rest of the
 * program, in order to ease the change of polyhedral library. For efficiency
 * reasons, they are defined and used as macros in domain.h.
 * - April 20th 2005: setting.
 *
Polyhedron * cloog_domain_polyhedron(CloogDomain * domain)
{ return domain->polyhedron ;
}

int cloog_domain_nbconstraints(CloogDomain * domain)
{ return domain->polyhedron->NbConstraints ;
}
 */

int cloog_domain_dimension(CloogDomain * domain)
{ return domain->polyhedron->Dimension ;
}

int cloog_scattering_dimension(CloogScattering *scatt, CloogDomain *domain)
{
    return cloog_domain_dimension(scatt) - cloog_domain_dimension(domain);
}

int cloog_domain_isconvex(CloogDomain * domain)
{ return (domain->polyhedron->next == NULL)? 1 : 0 ;
}


/**
 * cloog_domain_cut_first function:
 * This function splits off and returns the first convex set in the
 * union "domain".  The remainder of the union is returned in rest.
 * The original "domain" itself is destroyed and may not be used
 * after a call to this function.
 */
CloogDomain *cloog_domain_cut_first(CloogDomain *domain, CloogDomain **rest)
{
  if (!domain || !domain->polyhedron || cloog_domain_isconvex(domain)) {
    *rest = NULL;
    return domain;
  }

  if (domain->references == 1) {
    *rest = cloog_domain_alloc(domain->polyhedron->next);
    domain->polyhedron->next = NULL ;
    return domain;
  }

  cloog_domain_free(domain);
  *rest = cloog_domain_alloc(Domain_Copy(domain->polyhedron->next));
  return cloog_domain_alloc(Polyhedron_Copy(domain->polyhedron));
}


/**
 * Given a union domain, try to find a simpler representation
 * using fewer sets in the union.
 * Since PolyLib does not have a proper implementation for this
 * functionality, we compute
 *      convex(domain) \ (convex(domain) \ domain)
 * which usually approximates what we want.
 * The original "domain" itself is destroyed and may not be used
 * after a call to this function.
 */
CloogDomain *cloog_domain_simplify_union(CloogDomain *domain)
{
    CloogDomain *convex, *temp;

    convex = cloog_domain_convex(domain);
    temp = cloog_domain_difference(convex, domain);
    cloog_domain_free(domain);
    domain = cloog_domain_difference(convex, temp);
    cloog_domain_free(convex);
    cloog_domain_free(temp);

    return domain;
}


static int polyhedron_lazy_isconstant(Polyhedron *polyhedron, int dimension,
                                        cloog_int_t *value)
{
  int i, j;

  /* For each constraint... */
  for (i=0;i<polyhedron->NbConstraints;i++)
  { /* ...if it is concerned by the potentially scalar dimension... */
    if (value_notzero_p(polyhedron->Constraint[i][dimension+1]))
    { /* ...check that the constraint has the shape "dimension + scalar = 0". */
      for (j=0;j<=dimension;j++)
      if (value_notzero_p(polyhedron->Constraint[i][j]))
      return 0 ;
  
      if (value_notone_p(polyhedron->Constraint[i][dimension+1]))
      return 0 ;
  
      for (j=dimension+2;j<(polyhedron->Dimension + 1);j++)
      if (value_notzero_p(polyhedron->Constraint[i][j]))
      return 0 ;

      if (value) {
        value_assign(*value,polyhedron->Constraint[i][polyhedron->Dimension+1]);
        value_oppose(*value,*value);
      }
      return 1;
    }
  }
  
  return 0;
}


/**
 * cloog_scattering_lazy_isscalar function:
 * this function returns 1 if the dimension 'dimension' in the domain 'domain'
 * is scalar, this means that the only constraint on this dimension must have
 * the shape "x.dimension + scalar = 0" with x an integral variable. This
 * function is lazy since we only accept x=1 (further calculations are easier
 * in this way).
 * If value is not NULL, then it is set to the constant value of dimension.
 * - June 14th 2005: first version.
 * - June 21rd 2005: Adaptation for GMP.
 */
int cloog_scattering_lazy_isscalar(CloogScattering *domain, int dimension,
                                        cloog_int_t *value)
{
  return polyhedron_lazy_isconstant(domain->polyhedron, dimension, value);
}


/**
 * cloog_domain_lazy_isconstant function:
 * this function returns 1 if the dimension 'dimension' in the
 * domain 'domain' is constant.
 * If value is not NULL, then it is set to the constant value of dimension.
 */
int cloog_domain_lazy_isconstant(CloogDomain *domain, int dimension)
{
  return polyhedron_lazy_isconstant(domain->polyhedron, dimension, NULL);
}


/**
 * cloog_scattering_erase_dimension function:
 * this function returns a CloogDomain structure builds from 'domain' where
 * we removed the dimension 'dimension' and every constraint considering this
 * dimension. This is not a projection ! Every data concerning the
 * considered dimension is simply erased.
 * - June 14th 2005: first version.
 * - June 21rd 2005: Adaptation for GMP.
 */
CloogDomain *cloog_scattering_erase_dimension(CloogScattering *domain,
                                                int dimension)
{ int i, j, mi, nb_dim ;
  CloogMatrix * matrix ;
  CloogDomain * erased ;
  Polyhedron * polyhedron ;
 
  polyhedron = domain->polyhedron ;
  nb_dim = polyhedron->Dimension ;
  
  /* The matrix is one column less and at least one constraint less. */
  matrix = cloog_matrix_alloc(polyhedron->NbConstraints-1,nb_dim+1) ;
 
  /* mi is the constraint counter for the matrix. */
  mi = 0 ;
  for (i=0;i<polyhedron->NbConstraints;i++)
  if (value_zero_p(polyhedron->Constraint[i][dimension+1]))
  { for (j=0;j<=dimension;j++)
    value_assign(matrix->p[mi][j],polyhedron->Constraint[i][j]) ;
    
    for (j=dimension+2;j<nb_dim+2;j++)
    value_assign(matrix->p[mi][j-1],polyhedron->Constraint[i][j]) ;

    mi ++ ;
  }
  
  erased = cloog_domain_matrix2domain(matrix) ;
  cloog_matrix_free(matrix) ;

  return erased ;
}


/**
 * cloog_domain_cube:
 * Construct and return a dim-dimensional cube, with values ranging
 * between min and max in each dimension.
 */
CloogDomain *cloog_domain_cube(int dim, cloog_int_t min, cloog_int_t max,
                                CloogOptions *options)
{
  int i;
  Matrix *M;
  Polyhedron *P;

  M = Matrix_Alloc(2*dim, 2+dim);
  for (i = 0; i < dim; ++i) {
    value_set_si(M->p[2*i][0], 1);
    value_set_si(M->p[2*i][1+i], 1);
    value_oppose(M->p[2*i][1+dim], min);
    value_set_si(M->p[2*i+1][0], 1);
    value_set_si(M->p[2*i+1][1+i], -1);
    value_assign(M->p[2*i+1][1+dim], max);
  }
  P = Constraints2Polyhedron(M, MAX_RAYS);
  Matrix_Free(M);
  return cloog_domain_alloc(P);
}

/**
 * cloog_domain_scatter function:
 * This function add the scattering (scheduling) informations in a domain.
 */
CloogDomain *cloog_domain_scatter(CloogDomain *domain, CloogScattering *scatt)
{ int scatt_dim ;
  CloogDomain *ext, *newdom, *newpart, *temp;
  
  newdom = NULL ;
  scatt_dim = cloog_scattering_dimension(scatt, domain);
  
  /* For each polyhedron of domain (it can be an union of polyhedra). */
  while (domain != NULL)
  { /* Extend the domain by adding the scattering dimensions as the new
     * first domain dimensions.
     */
    ext = cloog_domain_extend(domain,scatt_dim,cloog_domain_dimension(domain)) ;
    /* Then add the scattering constraints. */
    newpart = cloog_domain_addconstraints(scatt,ext) ;
    cloog_domain_free(ext) ;

    if (newdom != NULL)
    { temp = newdom ;
      newdom = cloog_domain_union(newdom,newpart) ;
      cloog_domain_free(temp) ;
      cloog_domain_free(newpart) ;
    }
    else
    newdom = newpart ;
    
    /* We don't want to free the rest of the list. */
    temp = cloog_domain_cut_first(domain, &domain);
    cloog_domain_free(temp) ;
  }
  
  return newdom;
}