gitfan.cc File Reference

#include "kernel/mod2.h"
#include "Singular/dyn_modules/gfanlib/callgfanlib_conversion.h"
#include "Singular/dyn_modules/gfanlib/bbcone.h"
#include "Singular/dyn_modules/gfanlib/bbfan.h"
#include "Singular/mod_lib.h"
#include "gitfan.h"

Go to the source code of this file.

Namespaces
namespace	gitfan

Functions
void	gitfan::mergeFacets (facets &F, const facets &newFacets)
static gfan::ZCone	subcone (const lists &cones, const gfan::ZVector &point)
static gitfan::facets	interiorFacets (const gfan::ZCone &zc, const gfan::ZCone &bound)
BOOLEAN	refineCones (leftv res, leftv args)
static int	binomial (int n, int k)
intvec *	intToAface (unsigned int v0, int n, int k)
BOOLEAN	listOfAfacesToCheck (leftv res, leftv args)
BOOLEAN	nextAfaceToCheck (leftv res, leftv args)
BOOLEAN	checkSigns (leftv res, leftv args)
BOOLEAN	binaryToBigint (leftv res, leftv args)
BOOLEAN	composeIntvecs (leftv res, leftv args)
BOOLEAN	findPlaceToInsert (leftv res, leftv args)
int SI_MOD_INIT()	gitfan (SModulFunctions *p)

Function Documentation

binaryToBigint()

BOOLEAN binaryToBigint	(	leftv	res,
		leftv	args
	)

Definition at line 417 of file gitfan.cc.

{
  leftv u = args;
  if ((u != NULL) && (u->Typ() == INTVEC_CMD) && (u->next == NULL))
  {
    intvec* iv = (intvec*) u->Data();
    const int l = (iv->rows())*(iv->cols());
    number base = n_Init(2,coeffs_BIGINT);
    number endResult;
    n_Power(base,(*iv)[0]-1,&endResult,coeffs_BIGINT);
    for (int i=1; i<l; i++)
    {
      number endResultCache;
      number currentBit;
      n_Power(base,(*iv)[i]-1,&currentBit,coeffs_BIGINT);
      endResultCache = n_Add(endResult,currentBit,coeffs_BIGINT);
      n_Delete(&endResult,coeffs_BIGINT);
      n_Delete(&currentBit,coeffs_BIGINT);
      endResult = endResultCache;
      endResultCache = NULL;
    }
    n_Delete(&base,coeffs_BIGINT);
    res->rtyp = BIGINT_CMD;
    res->data = (void*) endResult;
    return FALSE;
  }
  WerrorS("binaryToBigint: unexpected parameter");
  return TRUE;
}

binomial()

static int binomial ( int  n, int  k  )

static

Definition at line 262 of file gitfan.cc.

{
  if (n<k)
    return(0);
  gfan::Integer num = 1;
  gfan::Integer den = 1;
  for (int i=1; i<=k; i++)
    den = den*i;
  for (int j=n-k+1; j<=n; j++)
    num = num*j;
  gfan::Integer bin = num/den;
  return(bin.toInt());
}

checkSigns()

BOOLEAN checkSigns	(	leftv	res,
		leftv	args
	)

Definition at line 368 of file gitfan.cc.

{
  leftv u = args;
  if ((u != NULL) && (u->Typ()==BIGINTMAT_CMD || u->Typ()==INTMAT_CMD))
  {
    leftv v = u->next;
    if ((v != NULL) && (v->Typ() == INTVEC_CMD) && (v->next == NULL))
    {
      bigintmat* interiorPoint = NULL;
      if (u->Typ() == INTMAT_CMD)
      {
        intvec* p0 = (intvec*) u->Data();
        interiorPoint = iv2bim(p0,coeffs_BIGINT);
      }
      else
        interiorPoint = (bigintmat*) u->Data();
      intvec* hash = (intvec*) v->Data();
      res->rtyp = INT_CMD;
      for (int i=0; i<hash->length(); i++)
      {
        if ( (*hash)[i]<0 && n_GreaterZero((*interiorPoint)[i],interiorPoint->basecoeffs()) )
        {
          res->data = (void*) (long) 0;
          return FALSE;
        }
        if ( (*hash)[i]>0 && !n_IsZero((*interiorPoint)[i],interiorPoint->basecoeffs()) )
        {
          number neg = n_Copy((*interiorPoint)[i],interiorPoint->basecoeffs());
          neg = n_InpNeg(neg,interiorPoint->basecoeffs());
          if (n_GreaterZero(neg,interiorPoint->basecoeffs()))
          {
            n_Delete(&neg,interiorPoint->basecoeffs());
            res->data = (void*) (long) 0;
            return FALSE;
          }
          n_Delete(&neg,interiorPoint->basecoeffs());
        }
      }
      res->data = (void*) (long) 1;
      if (v->Typ() == INTMAT_CMD)
        delete interiorPoint;
      return FALSE;
    }
  }
  WerrorS("checkSigns: unexpected parameter");
  return TRUE;
}

composeIntvecs()

BOOLEAN composeIntvecs	(	leftv	res,
		leftv	args
	)

Definition at line 448 of file gitfan.cc.

{
  leftv u = args;
  if ((u!=NULL) && (u->Typ()==INTVEC_CMD))
  {
    leftv v = u->next;
    if ((v!=NULL) && (v->Typ()==INTVEC_CMD) && (v->next==NULL))
    {
      intvec* iv1 = (intvec*) u->Data();
      intvec* iv2 = (intvec*) v->Data();
      int k = iv2->length();
      intvec* composedIntvec = new intvec(k);
      for (int i=0; i<k; i++)
        (*composedIntvec)[i] = (*iv1)[(*iv2)[i]-1];
      res->rtyp = INTVEC_CMD;
      res->data = (void*) composedIntvec;
      return FALSE;
    }
  }
  WerrorS("composeIntvecs: unexpected parameter");
  return TRUE;
}

findPlaceToInsert()

BOOLEAN findPlaceToInsert	(	leftv	res,
		leftv	args
	)

Definition at line 472 of file gitfan.cc.

{
  leftv u = args;
  if ((u!=NULL) && (u->Typ()==LIST_CMD))
  {
    leftv v = u->next;
    if ((v!=NULL) && (v->Typ()==BIGINT_CMD) && (v->next==NULL))
    {
      lists listOfNumbers = (lists) u->Data();
      number numberToInsert = (number) v->Data();
      int lowerBound = 0;
      int upperBound = lSize(listOfNumbers);
      if (upperBound<0)
      {
        res->rtyp = INT_CMD;
        res->data = (void*) (long) (lowerBound+1);
        return FALSE;
      }
 
      number lowerNumber = (number) listOfNumbers->m[lowerBound].Data();
      if (n_Equal(lowerNumber,numberToInsert,coeffs_BIGINT))
      {
        res->rtyp = INT_CMD;
        res->data = (void*) (long) (-1);
        return FALSE;
      }
      if (n_Greater(lowerNumber,numberToInsert,coeffs_BIGINT))
      {
        res->rtyp = INT_CMD;
        res->data = (void*) (long) (lowerBound+1);
        return FALSE;
      }
 
      number upperNumber = (number) listOfNumbers->m[upperBound].Data();
      if (n_Equal(numberToInsert,upperNumber,coeffs_BIGINT))
      {
        res->rtyp = INT_CMD;
        res->data = (void*) (long) (-1);
        return FALSE;
      }
      if (n_Greater(numberToInsert,upperNumber,coeffs_BIGINT))
      {
        res->rtyp = INT_CMD;
        res->data = (void*) (long) (upperBound+2);
        return FALSE;
      }
 
      while (lowerBound+1<upperBound)
      {
        int middle = lowerBound + (upperBound-lowerBound) / 2;
        number lowerNumber = (number) listOfNumbers->m[lowerBound].Data();
        number upperNumber = (number) listOfNumbers->m[upperBound].Data();
        number middleNumber = (number) listOfNumbers->m[middle].Data();
        if ((n_Equal(lowerNumber,numberToInsert,coeffs_BIGINT)) ||
            (n_Equal(middleNumber,numberToInsert,coeffs_BIGINT)) ||
            (n_Equal(upperNumber,numberToInsert,coeffs_BIGINT)))
        {
          res->rtyp = INT_CMD;
          res->data = (void*) (long) -1;
          return FALSE;
        }
        if (n_Greater(numberToInsert,middleNumber,coeffs_BIGINT))
          lowerBound = middle;
        if (n_Greater(middleNumber,numberToInsert,coeffs_BIGINT))
          upperBound = middle;
      }
 
      res->rtyp = INT_CMD;
      res->data = (void*) (long) (upperBound+1);
      return FALSE;
    }
  }
  WerrorS("findPlaceToInsert: unexpected parameter");
  return TRUE;
}

gitfan()

int SI_MOD_INIT() gitfan

(

SModulFunctions *

p

)

Definition at line 549 of file gitfan.cc.

{
  gfan::initializeCddlibIfRequired();
  p->iiAddCproc("gitfan.lib","refineCones",FALSE,refineCones);
  p->iiAddCproc("gitfan.lib","listOfAfacesToCheck",FALSE,listOfAfacesToCheck);
  p->iiAddCproc("gitfan.lib","nextAfaceToCheck",FALSE,nextAfaceToCheck);
  p->iiAddCproc("gitfan.lib","checkSigns",FALSE,checkSigns);
  p->iiAddCproc("gitfan.lib","binaryToBigint",FALSE,binaryToBigint);
  p->iiAddCproc("gitfan.lib","composeIntvecs",FALSE,composeIntvecs);
  p->iiAddCproc("gitfan.lib","findPlaceToInsert",FALSE,findPlaceToInsert);
  return (MAX_TOK);
}

interiorFacets()

static gitfan::facets interiorFacets ( const gfan::ZCone &  zc, const gfan::ZCone &  bound  )

static

Definition at line 104 of file gitfan.cc.

{
  gfan::ZMatrix inequalities = zc.getFacets();
  gfan::ZMatrix equations = zc.getImpliedEquations();
  int r = inequalities.getHeight();
  int c = inequalities.getWidth();
  gitfan::facets F;
  if (r*c == 0)
    /***
     * this is the trivial case where either we are in a zerodimensional ambient space,
     * or the cone has no facets.
     **/
    return F;
 
  // int index = 0;
  /* next we iterate over each of the r facets, build the respective cone and add it to the list */
  /* this is the i=0 case */
  gfan::ZMatrix newInequalities = inequalities.submatrix(1,0,r,c);
  gfan::ZMatrix newEquations = equations;
  newEquations.appendRow(inequalities[0]);
  gfan::ZCone eta = gfan::ZCone(newInequalities,newEquations);
  eta.canonicalize();
  gfan::ZVector v = eta.getRelativeInteriorPoint();
  gfan::ZVector w = inequalities[0];
 
  if (bound.containsRelatively(v))
    F.insert(gitfan::facet(eta,v,w));
 
  /* these are the cases i=1,...,r-2 */
  for (int i=1; i<r-1; i++)
  {
    newInequalities = inequalities.submatrix(0,0,i,c);
    newInequalities.append(inequalities.submatrix(i+1,0,r,c));
    newEquations = equations;
    newEquations.appendRow(inequalities[i]);
    eta = gfan::ZCone(newInequalities,newEquations);
    eta.canonicalize();
    v = eta.getRelativeInteriorPoint();
    w = inequalities[i];
    if (bound.containsRelatively(v))
      F.insert(gitfan::facet(eta,v,w));
  }
 
  /* this is the i=r-1 case */
  newInequalities = inequalities.submatrix(0,0,r-1,c);
  newEquations = equations;
  newEquations.appendRow(inequalities[r-1]);
  eta = gfan::ZCone(newInequalities,newEquations);
  eta.canonicalize();
 
  v = eta.getRelativeInteriorPoint();
  w = inequalities[r-1];
  if (bound.containsRelatively(v))
    F.insert(gitfan::facet(eta,v,w));
 
  return F;
}

intToAface()

intvec * intToAface	(	unsigned int	v0,
		int	n,
		int	k
	)

Definition at line 277 of file gitfan.cc.

{
  intvec* v = new intvec(k);
  int j = 0;
  for (int i=0; i<n; i++)
  {
    if (v0 & (1<<i))
      (*v)[j++] = i+1;
  }
  return v;
}

listOfAfacesToCheck()

BOOLEAN listOfAfacesToCheck	(	leftv	res,
		leftv	args
	)

Definition at line 290 of file gitfan.cc.

{
  leftv u = args;
  if ((u != NULL) && (u->Typ() == INT_CMD))
  {
    leftv v = u->next;
    if ((v != NULL) && (v->Typ() == INT_CMD))
    {
      int n = (int)(long) u->Data();
      int k = (int)(long) v->Data();
      unsigned int v = 0;
      for (int i=0; i<k; i++)
        v |= 1<<i;  // sets the first k bits of v as 1
 
      lists L = (lists)omAllocBin(slists_bin);
      int count = (int) binomial(n,k); L->Init(count);
      unsigned int t;
      while (!(v & (1<<n)))
      {
        L->m[--count].rtyp = INTVEC_CMD;
        L->m[count].data = (void*) intToAface(v,n,k);
 
        // t gets v's least significant 0 bits set to 1
        t = v | (v - 1);
        // Next set to 1 the most significant bit to change,
        // set to 0 the least significant ones, and add the necessary 1 bits.
        v = (t + 1) | (((~t & -~t) - 1) >> (__builtin_ctz(v) + 1));
      }
      res->rtyp = LIST_CMD;
      res->data = (void*) L;
      return FALSE;
    }
  }
  WerrorS("listOfAfacesToCheck: unexpected parameter");
  return TRUE;
}

nextAfaceToCheck()

BOOLEAN nextAfaceToCheck	(	leftv	res,
		leftv	args
	)

Definition at line 328 of file gitfan.cc.

{
  leftv u = args;
  if ((u != NULL) && (u->Typ() == INTVEC_CMD))
  {
    leftv v = u->next;
    if ((v != NULL) && (v->Typ() == INT_CMD))
    {
      leftv w = v->next;
      if ((w != NULL) && (w->Typ() == INT_CMD))
      {
        intvec* aface = (intvec*) u->Data();
        int ambientDimension = (int)(long) v->Data();
        int dimension = (int)(long) w->Data();
 
        unsigned int af = 0;
        for (int i=0; i<aface->length(); i++)
          af |= 1<<((*aface)[i]-1);
 
        unsigned int t = af | (af - 1);
        af = (t + 1) | (((~t & -~t) - 1) >> (__builtin_ctz(af) + 1));
 
        if (af & (1<<ambientDimension))
        {
          res->rtyp = INTVEC_CMD;
          res->data = (void*) new intvec(1);
          return FALSE;
        }
 
        res->rtyp = INTVEC_CMD;
        res->data = (void*) intToAface(af,ambientDimension,dimension);
        return FALSE;
      }
    }
  }
  WerrorS("nextAfaceToCheck: unexpected parameter");
  return TRUE;
}

refineCones()

BOOLEAN refineCones	(	leftv	res,
		leftv	args
	)

Definition at line 162 of file gitfan.cc.

{
  leftv u=args;
  if ((u != NULL) && (u->Typ() == LIST_CMD))
  {
    leftv v=u->next;
    if ((v != NULL) && (v->Typ() == BIGINTMAT_CMD))
    {
      lists cones = (lists) u->Data();
      bigintmat* bim = (bigintmat*) v->Data();
      gfan::ZMatrix* zm = bigintmatToZMatrix(bim->transpose());
      gfan::ZCone support = gfan::ZCone::givenByRays(*zm, gfan::ZMatrix(0, zm->getWidth()));
      delete zm;
 
      /***
       * Randomly compute a first full-dimensional cone and insert it into the fan.
       * Compute a list of facets and relative interior points.
       * The relative interior points are unique, assuming the cone is stored in canonical form,
       * which is the case in our algorithm, as we supply no redundant inequalities.
       * Hence we can decide whether a facet need to be traversed by crosschecking
       * its relative interior point with this list.
       **/
      gfan::ZCone lambda; gfan::ZVector point;
      do
      {
        point = randomPoint(&support);
        lambda = subcone(cones, point);
      }
      while (lambda.dimension() < lambda.ambientDimension());
      int iterationNumber = 1;
      std::cout << "cones found: " << iterationNumber++ << std::endl;
 
      lambda.canonicalize();
      gfan::ZFan* Sigma = new gfan::ZFan(lambda.ambientDimension());
      Sigma->insert(lambda);
      gitfan::facets F = interiorFacets(lambda, support);
      if (F.empty())
      {
        res->rtyp = fanID;
        res->data = (void*) Sigma;
        return FALSE;
      }
      int mu = 1024;
 
      gitfan::facet f;
      gfan::ZCone eta;
      gfan::ZVector interiorPoint;
      gfan::ZVector facetNormal;
      gitfan::facets newFacets;
      while (!F.empty())
      {
        /***
         * Extract a facet to traverse and its relative interior point.
         **/
        f = *(F.begin());
        eta = f.getEta();
        interiorPoint = f.getInteriorPoint();
        facetNormal = f.getFacetNormal();
 
        /***
         * construct a point, which lies on the other side of the facet.
         * make sure it lies in the known support of our fan
         * and that the cone around the point is maximal, containing eta.
         **/
        point = mu * interiorPoint - facetNormal;
        while (!support.containsRelatively(point))
        {
          mu = mu * 16;
          point = mu * interiorPoint - facetNormal;
        }
 
        lambda = subcone(cones,point);
        while ((lambda.dimension() < lambda.ambientDimension()) && !(lambda.contains(interiorPoint)))
        {
          mu = mu * 16;
          point = mu * interiorPoint - facetNormal;
          lambda = subcone(cones,point);
        }
        std::cout << "cones found: " << iterationNumber++ << std::endl;
 
        /***
         * insert lambda into Sigma, and create a list of facets of lambda.
         * merge the two lists of facets
         **/
        lambda.canonicalize();
        Sigma->insert(lambda);
        newFacets = interiorFacets(lambda, support);
        mergeFacets(F,newFacets);
        newFacets.clear();
      }
      res->rtyp = fanID;
      res->data = (void*) Sigma;
      return FALSE;
    }
  }
  WerrorS("refineCones: unexpected parameters");
  return TRUE;
}

subcone()

static gfan::ZCone subcone ( const lists &  cones, const gfan::ZVector &  point  )

static

Definition at line 91 of file gitfan.cc.

{
  gfan::ZCone sigma = gfan::ZCone(gfan::ZMatrix(1,point.size()), gfan::ZMatrix(1,point.size()));
  gfan::ZCone* zc;
  for (int i=0; i<=cones->nr; i++)
  {
    zc = (gfan::ZCone*) cones->m[i].Data();
    if (zc->contains(point))
      sigma = gfan::intersection(sigma,*zc);
  }
  return(sigma);
}