groebnerCone Class Reference

#include <groebnerCone.h>

Public Member Functions
	groebnerCone ()
	groebnerCone (const ideal I, const ring r, const tropicalStrategy &currentCase)
	groebnerCone (const ideal I, const ring r, const gfan::ZVector &w, const tropicalStrategy &currentCase)
	groebnerCone (const ideal I, const ring r, const gfan::ZVector &u, const gfan::ZVector &w, const tropicalStrategy &currentCase)
	groebnerCone (const ideal I, const ideal inI, const ring r, const tropicalStrategy &currentCase)
	groebnerCone (const groebnerCone &sigma)
	~groebnerCone ()
groebnerCone &	operator= (const groebnerCone &sigma)
void	deletePolynomialData ()
ideal	getPolynomialIdeal () const
ring	getPolynomialRing () const
gfan::ZCone	getPolyhedralCone () const
gfan::ZVector	getInteriorPoint () const
const tropicalStrategy *	getTropicalStrategy () const
bool	isTrivial () const
bool	contains (const gfan::ZVector &w) const
	Returns true if Groebner cone contains w, false otherwise. More...
gfan::ZVector	tropicalPoint () const
	Returns a point in the tropical variety, if the groebnerCone contains one. More...
groebnerCone	flipCone (const gfan::ZVector &interiorPoint, const gfan::ZVector &facetNormal) const
	Given an interior point on the facet and the outer normal factor on the facet, returns the adjacent groebnerCone sharing that facet. More...
groebnerCones	groebnerNeighbours () const
	Returns a complete list of neighboring Groebner cones. More...
groebnerCones	tropicalNeighbours () const
	Returns a complete list of neighboring Groebner cones in the tropical variety. More...
bool	pointsOutwards (const gfan::ZVector w) const
	Return 1 if w points is in the dual of the polyhedral cone, 0 otherwise. More...
bool	checkFlipConeInput (const gfan::ZVector interiorPoint, const gfan::ZVector facetNormal) const
	Debug tools. More...

Private Attributes
ideal	polynomialIdeal
	ideal to which this Groebner cone belongs to More...
ring	polynomialRing
	ring in which the ideal exists More...
gfan::ZCone	polyhedralCone
gfan::ZVector	interiorPoint
const tropicalStrategy *	currentStrategy

Friends
struct	groebnerCone_compare

Detailed Description

Definition at line 27 of file groebnerCone.h.

Constructor & Destructor Documentation

groebnerCone() [1/6]

groebnerCone::groebnerCone

(

)

Definition at line 69 of file groebnerCone.cc.

                          :
  polynomialIdeal(NULL),
  polynomialRing(NULL),
  polyhedralCone(gfan::ZCone(0)),
  interiorPoint(gfan::ZVector(0)),
  currentStrategy(NULL)
{
}

groebnerCone() [2/6]

groebnerCone::groebnerCone	(	const ideal	I,
		const ring	r,
		const tropicalStrategy &	currentCase
	)

Definition at line 78 of file groebnerCone.cc.

                                                                                          :
  polynomialIdeal(NULL),
  polynomialRing(NULL),
  currentStrategy(&currentCase)
{
  assume(checkPolynomialInput(I,r));
  if (r) polynomialRing = rCopy(r);
  if (I)
  {
    polynomialIdeal = id_Copy(I,r);
    currentCase.pReduce(polynomialIdeal,polynomialRing);
    currentCase.reduce(polynomialIdeal,polynomialRing);
  }
 
  int n = rVar(polynomialRing);
  poly g = NULL;
  int* leadexpv = (int*) omAlloc((n+1)*sizeof(int));
  int* tailexpv = (int*) omAlloc((n+1)*sizeof(int));
  gfan::ZVector leadexpw = gfan::ZVector(n);
  gfan::ZVector tailexpw = gfan::ZVector(n);
  gfan::ZMatrix inequalities = gfan::ZMatrix(0,n);
  for (int i=0; i<IDELEMS(polynomialIdeal); i++)
  {
    g = polynomialIdeal->m[i];
    if (g)
    {
      p_GetExpV(g,leadexpv,r);
      leadexpw = expvToZVector(n, leadexpv);
      pIter(g);
      while (g)
      {
        p_GetExpV(g,tailexpv,r);
        tailexpw = expvToZVector(n, tailexpv);
        inequalities.appendRow(leadexpw-tailexpw);
        pIter(g);
      }
    }
  }
  omFreeSize(leadexpv,(n+1)*sizeof(int));
  omFreeSize(tailexpv,(n+1)*sizeof(int));
  // if (currentStrategy->restrictToLowerHalfSpace())
  // {
  //   gfan::ZVector lowerHalfSpaceCondition = gfan::ZVector(n);
  //   lowerHalfSpaceCondition[0] = -1;
  //   inequalities.appendRow(lowerHalfSpaceCondition);
  // }
 
  polyhedralCone = gfan::ZCone(inequalities,gfan::ZMatrix(0, inequalities.getWidth()));
  polyhedralCone.canonicalize();
  interiorPoint = polyhedralCone.getRelativeInteriorPoint();
  assume(checkOrderingAndCone(polynomialRing,polyhedralCone));
}

groebnerCone() [3/6]

groebnerCone::groebnerCone	(	const ideal	I,
		const ring	r,
		const gfan::ZVector &	w,
		const tropicalStrategy &	currentCase
	)

Definition at line 131 of file groebnerCone.cc.

                                                                                                                :
  polynomialIdeal(NULL),
  polynomialRing(NULL),
  currentStrategy(&currentCase)
{
  assume(checkPolynomialInput(I,r));
  if (r) polynomialRing = rCopy(r);
  if (I)
  {
    polynomialIdeal = id_Copy(I,r);
    currentCase.pReduce(polynomialIdeal,polynomialRing);
    currentCase.reduce(polynomialIdeal,polynomialRing);
  }
 
  int n = rVar(polynomialRing);
  gfan::ZMatrix inequalities = gfan::ZMatrix(0,n);
  gfan::ZMatrix equations = gfan::ZMatrix(0,n);
  int* expv = (int*) omAlloc((n+1)*sizeof(int));
  for (int i=0; i<IDELEMS(polynomialIdeal); i++)
  {
    poly g = polynomialIdeal->m[i];
    if (g)
    {
      p_GetExpV(g,expv,polynomialRing);
      gfan::ZVector leadexpv = intStar2ZVector(n,expv);
      long d = wDeg(g,polynomialRing,w);
      for (pIter(g); g; pIter(g))
      {
        p_GetExpV(g,expv,polynomialRing);
        gfan::ZVector tailexpv = intStar2ZVector(n,expv);
        if (wDeg(g,polynomialRing,w)==d)
          equations.appendRow(leadexpv-tailexpv);
        else
        {
          assume(wDeg(g,polynomialRing,w)<d);
          inequalities.appendRow(leadexpv-tailexpv);
        }
      }
    }
  }
  omFreeSize(expv,(n+1)*sizeof(int));
  // if (currentStrategy->restrictToLowerHalfSpace())
  // {
  //   gfan::ZVector lowerHalfSpaceCondition = gfan::ZVector(n);
  //   lowerHalfSpaceCondition[0] = -1;
  //   inequalities.appendRow(lowerHalfSpaceCondition);
  // }
 
  polyhedralCone = gfan::ZCone(inequalities,equations);
  polyhedralCone.canonicalize();
  interiorPoint = polyhedralCone.getRelativeInteriorPoint();
  assume(checkOrderingAndCone(polynomialRing,polyhedralCone));
}

groebnerCone() [4/6]

groebnerCone::groebnerCone	(	const ideal	I,
		const ring	r,
		const gfan::ZVector &	u,
		const gfan::ZVector &	w,
		const tropicalStrategy &	currentCase
	)

Definition at line 189 of file groebnerCone.cc.

                                                                                                                                      :
  polynomialIdeal(NULL),
  polynomialRing(NULL),
  currentStrategy(&currentCase)
{
  assume(checkWeightVector(I,r,u));
  assume(checkPolynomialInput(I,r));
  if (r) polynomialRing = rCopy(r);
  if (I)
  {
    polynomialIdeal = id_Copy(I,r);
    currentCase.pReduce(polynomialIdeal,polynomialRing);
    currentCase.reduce(polynomialIdeal,polynomialRing);
  }
 
  int n = rVar(polynomialRing);
  gfan::ZMatrix inequalities = gfan::ZMatrix(0,n);
  gfan::ZMatrix equations = gfan::ZMatrix(0,n);
  int* expv = (int*) omAlloc((n+1)*sizeof(int));
  for (int i=0; i<IDELEMS(polynomialIdeal); i++)
  {
    poly g = polynomialIdeal->m[i];
    if (g)
    {
      p_GetExpV(g,expv,polynomialRing);
      gfan::ZVector leadexpv = intStar2ZVector(n,expv);
      long d1 = wDeg(g,polynomialRing,u);
      long d2 = wDeg(g,polynomialRing,w);
      for (pIter(g); g; pIter(g))
      {
        p_GetExpV(g,expv,polynomialRing);
        gfan::ZVector tailexpv = intStar2ZVector(n,expv);
        if (wDeg(g,polynomialRing,u)==d1 && wDeg(g,polynomialRing,w)==d2)
          equations.appendRow(leadexpv-tailexpv);
        else
        {
          assume(wDeg(g,polynomialRing,u)<d1 || wDeg(g,polynomialRing,w)<d2);
          inequalities.appendRow(leadexpv-tailexpv);
        }
      }
    }
  }
  omFreeSize(expv,(n+1)*sizeof(int));
  // if (currentStrategy->restrictToLowerHalfSpace())
  // {
  //   gfan::ZVector lowerHalfSpaceCondition = gfan::ZVector(n);
  //   lowerHalfSpaceCondition[0] = -1;
  //   inequalities.appendRow(lowerHalfSpaceCondition);
  // }
 
  polyhedralCone = gfan::ZCone(inequalities,equations);
  polyhedralCone.canonicalize();
  interiorPoint = polyhedralCone.getRelativeInteriorPoint();
  assume(checkOrderingAndCone(polynomialRing,polyhedralCone));
}

groebnerCone() [5/6]

groebnerCone::groebnerCone	(	const ideal	I,
		const ideal	inI,
		const ring	r,
		const tropicalStrategy &	currentCase
	)

Definition at line 246 of file groebnerCone.cc.

                                                                                                           :
  polynomialIdeal(id_Copy(I,r)),
  polynomialRing(rCopy(r)),
  currentStrategy(&currentCase)
{
  assume(checkPolynomialInput(I,r));
  assume(checkPolynomialInput(inI,r));
 
  currentCase.pReduce(polynomialIdeal,polynomialRing);
  currentCase.reduce(polynomialIdeal,polynomialRing);
 
  int n = rVar(r);
  gfan::ZMatrix equations = gfan::ZMatrix(0,n);
  int* expv = (int*) omAlloc((n+1)*sizeof(int));
  for (int i=0; i<IDELEMS(inI); i++)
  {
    poly g = inI->m[i];
    if (g)
    {
      p_GetExpV(g,expv,r);
      gfan::ZVector leadexpv = intStar2ZVector(n,expv);
      for (pIter(g); g; pIter(g))
      {
        p_GetExpV(g,expv,r);
        gfan::ZVector tailexpv = intStar2ZVector(n,expv);
        equations.appendRow(leadexpv-tailexpv);
      }
    }
  }
  gfan::ZMatrix inequalities = gfan::ZMatrix(0,n);
  for (int i=0; i<IDELEMS(polynomialIdeal); i++)
  {
    poly g = polynomialIdeal->m[i];
    if (g)
    {
      p_GetExpV(g,expv,r);
      gfan::ZVector leadexpv = intStar2ZVector(n,expv);
      for (pIter(g); g; pIter(g))
      {
        p_GetExpV(g,expv,r);
        gfan::ZVector tailexpv = intStar2ZVector(n,expv);
        inequalities.appendRow(leadexpv-tailexpv);
      }
    }
  }
  omFreeSize(expv,(n+1)*sizeof(int));
  if (currentStrategy->restrictToLowerHalfSpace())
  {
    gfan::ZVector lowerHalfSpaceCondition = gfan::ZVector(n);
    lowerHalfSpaceCondition[0] = -1;
    inequalities.appendRow(lowerHalfSpaceCondition);
  }
 
  polyhedralCone = gfan::ZCone(inequalities,equations);
  polyhedralCone.canonicalize();
  interiorPoint = polyhedralCone.getRelativeInteriorPoint();
  assume(checkOrderingAndCone(polynomialRing,polyhedralCone));
}

groebnerCone() [6/6]

groebnerCone::groebnerCone

(

const groebnerCone &

sigma

)

Definition at line 305 of file groebnerCone.cc.

                                                   :
  polynomialIdeal(NULL),
  polynomialRing(NULL),
  polyhedralCone(gfan::ZCone(sigma.getPolyhedralCone())),
  interiorPoint(gfan::ZVector(sigma.getInteriorPoint())),
  currentStrategy(sigma.getTropicalStrategy())
{
  assume(checkPolynomialInput(sigma.getPolynomialIdeal(),sigma.getPolynomialRing()));
  assume(checkOrderingAndCone(sigma.getPolynomialRing(),sigma.getPolyhedralCone()));
  assume(checkPolyhedralInput(sigma.getPolyhedralCone(),sigma.getInteriorPoint()));
  if (sigma.getPolynomialIdeal()) polynomialIdeal = id_Copy(sigma.getPolynomialIdeal(),sigma.getPolynomialRing());
  if (sigma.getPolynomialRing()) polynomialRing = rCopy(sigma.getPolynomialRing());
}

~groebnerCone()

groebnerCone::~groebnerCone

(

)

Definition at line 319 of file groebnerCone.cc.

{
  assume(checkPolynomialInput(polynomialIdeal,polynomialRing));
  assume(checkOrderingAndCone(polynomialRing,polyhedralCone));
  assume(checkPolyhedralInput(polyhedralCone,interiorPoint));
  if (polynomialIdeal) id_Delete(&polynomialIdeal,polynomialRing);
  if (polynomialRing) rDelete(polynomialRing);
}

Member Function Documentation

checkFlipConeInput()

bool groebnerCone::checkFlipConeInput	(	const gfan::ZVector	interiorPoint,
		const gfan::ZVector	facetNormal
	)		const

Debug tools.

Definition at line 23 of file groebnerCone.cc.

{
  /* check first whether interiorPoint lies on the boundary of the cone */
  if (!polyhedralCone.contains(interiorPoint))
  {
    std::cout << "ERROR: interiorPoint is not contained in the Groebner cone!" << std::endl
              << "cone: " << std::endl
              << toString(&polyhedralCone)
              << "interiorPoint:" << std::endl
              << interiorPoint << std::endl;
    return false;
  }
  if (polyhedralCone.containsRelatively(interiorPoint))
  {
    std::cout << "ERROR: interiorPoint is contained in the interior of the maximal Groebner cone!" << std::endl
              << "cone: " << std::endl
              << toString(&polyhedralCone)
              << "interiorPoint:" << std::endl
              << interiorPoint << std::endl;
    return false;
  }
  gfan::ZCone hopefullyAFacet = polyhedralCone.faceContaining(interiorPoint);
  if (hopefullyAFacet.dimension()!=(polyhedralCone.dimension()-1))
  {
    std::cout << "ERROR: interiorPoint is not contained in the interior of a facet!" << std::endl
              << "cone: " << std::endl
              << toString(&polyhedralCone)
              << "interiorPoint:" << std::endl
              << interiorPoint << std::endl;
    return false;
  }
  /* check whether facet normal points outwards */
  gfan::ZCone dual = polyhedralCone.dualCone();
  if(dual.containsRelatively(facetNormal))
  {
    std::cout << "ERROR: facetNormal is not pointing outwards!" << std::endl
              << "cone: " << std::endl
              << toString(&polyhedralCone)
              << "facetNormal:" << std::endl
              << facetNormal << std::endl;
    return false;
  }
  return true;
}

contains()

bool groebnerCone::contains

(

const gfan::ZVector &

w

)

const

Returns true if Groebner cone contains w, false otherwise.

Definition at line 344 of file groebnerCone.cc.

{
  return polyhedralCone.contains(w);
}

deletePolynomialData()

void groebnerCone::deletePolynomialData ( )

inline

Definition at line 53 of file groebnerCone.h.

  {
    assume ((!polynomialIdeal) || (polynomialIdeal && polynomialRing));
    if (polynomialIdeal) id_Delete(&polynomialIdeal,polynomialRing);
    if (polynomialRing) rDelete(polynomialRing);
    polynomialIdeal = NULL;
    polynomialRing = NULL;
  }

flipCone()

groebnerCone groebnerCone::flipCone	(	const gfan::ZVector &	interiorPoint,
		const gfan::ZVector &	facetNormal
	)		const

Given an interior point on the facet and the outer normal factor on the facet, returns the adjacent groebnerCone sharing that facet.

Definition at line 383 of file groebnerCone.cc.

{
  assume(this->checkFlipConeInput(interiorPoint,facetNormal));
  assume(checkWeightVector(polynomialIdeal,polynomialRing,interiorPoint));
  /* Note: the polynomial ring created will have a weighted ordering with respect to interiorPoint
   *   and with a weighted ordering with respect to facetNormal as tiebreaker.
   *   Hence it is sufficient to compute the initial form with respect to facetNormal,
   *   to obtain an initial form with respect to interiorPoint+e*facetNormal,
   *   for e>0 sufficiently small */
  std::pair<ideal,ring> flipped = currentStrategy->computeFlip(polynomialIdeal,polynomialRing,interiorPoint,facetNormal);
  assume(checkPolynomialInput(flipped.first,flipped.second));
  groebnerCone flippedCone(flipped.first, flipped.second, interiorPoint, facetNormal, *currentStrategy);
  id_Delete(&flipped.first,flipped.second);
  rDelete(flipped.second);
  return flippedCone;
}

getInteriorPoint()

gfan::ZVector groebnerCone::getInteriorPoint ( ) const

inline

Definition at line 65 of file groebnerCone.h.

{ return interiorPoint; };

getPolyhedralCone()

gfan::ZCone groebnerCone::getPolyhedralCone ( ) const

inline

Definition at line 64 of file groebnerCone.h.

{ return polyhedralCone; };

getPolynomialIdeal()

ideal groebnerCone::getPolynomialIdeal ( ) const

inline

Definition at line 62 of file groebnerCone.h.

{ return polynomialIdeal; };

getPolynomialRing()

ring groebnerCone::getPolynomialRing ( ) const

inline

Definition at line 63 of file groebnerCone.h.

{ return polynomialRing; };

getTropicalStrategy()

const tropicalStrategy * groebnerCone::getTropicalStrategy ( ) const

inline

Definition at line 66 of file groebnerCone.h.

{ return currentStrategy; };

groebnerNeighbours()

groebnerCones groebnerCone::groebnerNeighbours

(

)

const

Returns a complete list of neighboring Groebner cones.

Definition at line 404 of file groebnerCone.cc.

{
  std::pair<gfan::ZMatrix, gfan::ZMatrix> facetsData = interiorPointsAndNormalsOfFacets(polyhedralCone);
 
  gfan::ZMatrix interiorPoints = facetsData.first;
  gfan::ZMatrix facetNormals = facetsData.second;
 
  groebnerCones neighbours;
  for (int i=0; i<interiorPoints.getHeight(); i++)
  {
    gfan::ZVector w = interiorPoints[i];
    gfan::ZVector v = facetNormals[i];
    if (currentStrategy->restrictToLowerHalfSpace())
    {
      assume(w[0].sign()<=0);
      if (w[0].sign()==0 && v[0].sign()>0)
        continue;
    }
    neighbours.insert(flipCone(w,v));
  }
  return neighbours;
}

isTrivial()

bool groebnerCone::isTrivial ( ) const

inline

Definition at line 69 of file groebnerCone.h.

  {
    bool b = (polynomialRing==NULL);
    return b;
  }

operator=()

groebnerCone & groebnerCone::operator=

(

const groebnerCone &

sigma

)

Definition at line 328 of file groebnerCone.cc.

{
  assume(checkPolynomialInput(sigma.getPolynomialIdeal(),sigma.getPolynomialRing()));
  assume(checkOrderingAndCone(sigma.getPolynomialRing(),sigma.getPolyhedralCone()));
  assume(checkPolyhedralInput(sigma.getPolyhedralCone(),sigma.getInteriorPoint()));
  if (sigma.getPolynomialIdeal()) polynomialIdeal = id_Copy(sigma.getPolynomialIdeal(),sigma.getPolynomialRing());
  if (sigma.getPolynomialRing()) polynomialRing = rCopy(sigma.getPolynomialRing());
  polyhedralCone = sigma.getPolyhedralCone();
  interiorPoint = sigma.getInteriorPoint();
  currentStrategy = sigma.getTropicalStrategy();
  return *this;
}

pointsOutwards()

bool groebnerCone::pointsOutwards

(

const gfan::ZVector

w

)

const

Return 1 if w points is in the dual of the polyhedral cone, 0 otherwise.

Definition at line 428 of file groebnerCone.cc.

{
  gfan::ZCone dual = polyhedralCone.dualCone();
  return (!dual.contains(w));
}

tropicalNeighbours()

groebnerCones groebnerCone::tropicalNeighbours

(

)

const

Returns a complete list of neighboring Groebner cones in the tropical variety.

Definition at line 438 of file groebnerCone.cc.

{
  gfan::ZMatrix interiorPoints = interiorPointsOfFacets(polyhedralCone);
  groebnerCones neighbours;
  for (int i=0; i<interiorPoints.getHeight(); i++)
  {
    if (!(currentStrategy->restrictToLowerHalfSpace() && interiorPoints[i][0].sign()==0))
    {
      ideal initialIdeal = initial(polynomialIdeal,polynomialRing,interiorPoints[i]);
      gfan::ZMatrix ray = raysOfTropicalStar(initialIdeal,polynomialRing,interiorPoints[i],currentStrategy);
      for (int j=0; j<ray.getHeight(); j++)
        if (pointsOutwards(ray[j]))
        {
          groebnerCone neighbour = flipCone(interiorPoints[i],ray[j]);
          neighbours.insert(neighbour);
        }
      id_Delete(&initialIdeal,polynomialRing);
    }
  }
  return neighbours;
}

tropicalPoint()

gfan::ZVector groebnerCone::tropicalPoint

(

)

const

Returns a point in the tropical variety, if the groebnerCone contains one.

Returns an empty vector otherwise.

Definition at line 354 of file groebnerCone.cc.

{
  assume(checkOrderingAndCone(polynomialRing,polyhedralCone));
  ideal I = polynomialIdeal;
  ring r = polynomialRing;
 
  gfan::ZCone coneToCheck = polyhedralCone;
  gfan::ZMatrix R = coneToCheck.extremeRays();
  for (int i=0; i<R.getHeight(); i++)
  {
    assume(!currentStrategy->restrictToLowerHalfSpace() || R[i][0].sign()<=0);
    if (currentStrategy->restrictToLowerHalfSpace() && R[i][0].sign()==0)
      continue;
    std::pair<poly,int> s = currentStrategy->checkInitialIdealForMonomial(I,r,R[i]);
    if (s.first==NULL)
    {
      if (s.second<0)
        // if monomial was initialized, delete it
        p_Delete(&s.first,r);
      return R[i];
    }
  }
  return gfan::ZVector();
}

Friends And Related Function Documentation

groebnerCone_compare

friend struct groebnerCone_compare

friend

Definition at line 67 of file groebnerCone.h.

Field Documentation

currentStrategy

const tropicalStrategy* groebnerCone::currentStrategy

private

Definition at line 41 of file groebnerCone.h.

interiorPoint

gfan::ZVector groebnerCone::interiorPoint

private

Definition at line 40 of file groebnerCone.h.

polyhedralCone

gfan::ZCone groebnerCone::polyhedralCone

private

Definition at line 39 of file groebnerCone.h.

polynomialIdeal

ideal groebnerCone::polynomialIdeal

private

ideal to which this Groebner cone belongs to

Definition at line 34 of file groebnerCone.h.

polynomialRing

ring groebnerCone::polynomialRing

private

ring in which the ideal exists

Definition at line 38 of file groebnerCone.h.

---

The documentation for this class was generated from the following files:

• Singular/dyn_modules/gfanlib/groebnerCone.h
• Singular/dyn_modules/gfanlib/groebnerCone.cc