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class TGraphDelaunay: public TNamed

 TGraphDelaunay generates a Delaunay triangulation of a TGraph2D. This
 triangulation code derives from an implementation done by Luke Jones
 (Royal Holloway, University of London) in April 2002 in the PAW context.

 This software cannot be guaranteed to work under all circumstances. They
 were originally written to work with a few hundred points in an XY space
 with similar X and Y ranges.

 Definition of Delaunay triangulation (After B. Delaunay):
 For a set S of points in the Euclidean plane, the unique triangulation DT(S)
 of S such that no point in S is inside the circumcircle of any triangle in
 DT(S). DT(S) is the dual of the Voronoi diagram of S. If n is the number of
 points in S, the Voronoi diagram of S is the partitioning of the plane
 containing S points into n convex polygons such that each polygon contains
 exactly one point and every point in a given polygon is closer to its
 central point than to any other. A Voronoi diagram is sometimes also known
 as a Dirichlet tessellation.

This applet gives a nice practical view of Delaunay triangulation and Voronoi diagram. */

Function Members (Methods)

TGraphDelaunay(TGraph2D* g)
voidTObject::AbstractMethod(const char* method) const
virtual voidTObject::AppendPad(Option_t* option = "")
virtual voidTObject::Browse(TBrowser* b)
static TClass*Class()
virtual const char*TObject::ClassName() const
virtual voidTNamed::Clear(Option_t* option = "")
virtual TObject*TNamed::Clone(const char* newname = "") const
virtual Int_tTNamed::Compare(const TObject* obj) const
Double_tComputeZ(Double_t x, Double_t y)
virtual voidTNamed::Copy(TObject& named) const
virtual voidTObject::Delete(Option_t* option = "")MENU
virtual Int_tTObject::DistancetoPrimitive(Int_t px, Int_t py)
virtual voidTObject::Draw(Option_t* option = "")
virtual voidTObject::DrawClass() constMENU
virtual TObject*TObject::DrawClone(Option_t* option = "") constMENU
virtual voidTObject::Dump() constMENU
virtual voidTObject::Error(const char* method, const char* msgfmt) const
virtual voidTObject::Execute(const char* method, const char* params, Int_t* error = 0)
virtual voidTObject::Execute(TMethod* method, TObjArray* params, Int_t* error = 0)
virtual voidTObject::ExecuteEvent(Int_t event, Int_t px, Int_t py)
virtual voidTObject::Fatal(const char* method, const char* msgfmt) const
virtual voidTNamed::FillBuffer(char*& buffer)
virtual TObject*TObject::FindObject(const char* name) const
virtual TObject*TObject::FindObject(const TObject* obj) const
virtual Option_t*TObject::GetDrawOption() const
static Long_tTObject::GetDtorOnly()
TGraph2D*GetGraph2D() const
virtual const char*TObject::GetIconName() const
Double_tGetMarginBinsContent() const
Int_t*GetMTried() const
virtual const char*TNamed::GetName() const
Int_tGetNdt() const
Int_t*GetNTried() const
virtual char*TObject::GetObjectInfo(Int_t px, Int_t py) const
static Bool_tTObject::GetObjectStat()
virtual Option_t*TObject::GetOption() const
Int_t*GetPTried() const
virtual const char*TNamed::GetTitle() const
virtual UInt_tTObject::GetUniqueID() const
Double_t*GetXN() const
Double_tGetXNmax() const
Double_tGetXNmin() const
Double_t*GetYN() const
Double_tGetYNmax() const
Double_tGetYNmin() const
virtual Bool_tTObject::HandleTimer(TTimer* timer)
virtual ULong_tTNamed::Hash() const
virtual voidTObject::Info(const char* method, const char* msgfmt) const
virtual Bool_tTObject::InheritsFrom(const char* classname) const
virtual Bool_tTObject::InheritsFrom(const TClass* cl) const
virtual voidTObject::Inspect() constMENU
Double_tInterpolate(Double_t x, Double_t y)
voidTObject::InvertBit(UInt_t f)
virtual TClass*IsA() const
virtual Bool_tTObject::IsEqual(const TObject* obj) const
virtual Bool_tTObject::IsFolder() const
Bool_tTObject::IsOnHeap() const
virtual Bool_tTNamed::IsSortable() const
Bool_tTObject::IsZombie() const
virtual voidTNamed::ls(Option_t* option = "") const
voidTObject::MayNotUse(const char* method) const
virtual Bool_tTObject::Notify()
voidTObject::Obsolete(const char* method, const char* asOfVers, const char* removedFromVers) const
static voidTObject::operator delete(void* ptr)
static voidTObject::operator delete(void* ptr, void* vp)
static voidTObject::operator delete[](void* ptr)
static voidTObject::operator delete[](void* ptr, void* vp)
void*TObject::operator new(size_t sz)
void*TObject::operator new(size_t sz, void* vp)
void*TObject::operator new[](size_t sz)
void*TObject::operator new[](size_t sz, void* vp)
virtual voidTObject::Paint(Option_t* option = "")
virtual voidTObject::Pop()
virtual voidTNamed::Print(Option_t* option = "") const
virtual Int_tTObject::Read(const char* name)
virtual voidTObject::RecursiveRemove(TObject* obj)
voidTObject::ResetBit(UInt_t f)
virtual voidTObject::SaveAs(const char* filename = "", Option_t* option = "") constMENU
virtual voidTObject::SavePrimitive(ostream& out, Option_t* option = "")
voidTObject::SetBit(UInt_t f)
voidTObject::SetBit(UInt_t f, Bool_t set)
virtual voidTObject::SetDrawOption(Option_t* option = "")MENU
static voidTObject::SetDtorOnly(void* obj)
voidSetMarginBinsContent(Double_t z = 0.)
voidSetMaxIter(Int_t n = 100000)
virtual voidTNamed::SetName(const char* name)MENU
virtual voidTNamed::SetNameTitle(const char* name, const char* title)
static voidTObject::SetObjectStat(Bool_t stat)
virtual voidTNamed::SetTitle(const char* title = "")MENU
virtual voidTObject::SetUniqueID(UInt_t uid)
virtual voidShowMembers(TMemberInspector& insp)
virtual Int_tTNamed::Sizeof() const
virtual voidStreamer(TBuffer& b)
voidStreamerNVirtual(TBuffer& b)
virtual voidTObject::SysError(const char* method, const char* msgfmt) const
Bool_tTObject::TestBit(UInt_t f) const
Int_tTObject::TestBits(UInt_t f) const
virtual voidTObject::UseCurrentStyle()
virtual voidTObject::Warning(const char* method, const char* msgfmt) const
virtual Int_tTObject::Write(const char* name = 0, Int_t option = 0, Int_t bufsize = 0)
virtual Int_tTObject::Write(const char* name = 0, Int_t option = 0, Int_t bufsize = 0) const
virtual voidTObject::DoError(int level, const char* location, const char* fmt, va_list va) const
Bool_tEnclose(Int_t T1, Int_t T2, Int_t T3, Int_t Ex) const
voidFileIt(Int_t P, Int_t N, Int_t M)
Bool_tInHull(Int_t E, Int_t X) const
Double_tInterpolateOnPlane(Int_t TI1, Int_t TI2, Int_t TI3, Int_t E) const

Data Members

Bool_tfAllTri!True if FindAllTriangles() has been performed on fGraph2D
Double_t*fDist!Array used to order mass points by distance
TGraph2D*fGraph2D!2D graph containing the user data
Int_t*fHullPoints!Hull points of size fNhull
Bool_tfInit!True if CreateTrianglesDataStructure() and FindHull() have been performed
Int_tfMaxIter!Maximum number of iterations to find Delaunay triangles
Int_t*fNTried!Delaunay triangles storage of size fNdt
TStringTNamed::fNameobject identifier
Int_tfNdt!Number of Delaunay triangles found
Int_tfNhull!Number of points in the hull
Int_tfNpoints!Number of data points in fGraph2D
Int_t*fOrder!Array used to order mass points by distance
TStringTNamed::fTitleobject title
Int_tfTriedSize!Real size of the fxTried arrays
Double_t*fX!Pointer to fGraph2D->fX
Double_t*fXN!fGraph2D vectors normalized of size fNpoints
Double_tfXNmax!Maximum value of fXN
Double_tfXNmin!Minimum value of fXN
Double_t*fY!Pointer to fGraph2D->fY
Double_t*fYN!fGraph2D vectors normalized of size fNpoints
Double_tfYNmax!Maximum value of fYN
Double_tfYNmin!Minimum value of fYN
Double_tfYoffset!Parameters used to normalize user data
Double_t*fZ!Pointer to fGraph2D->fZ
Double_tfZout!Histogram bin height for points lying outside the convex hull

Class Charts

Inheritance Inherited Members Includes Libraries
Class Charts

Function documentation

 TGraphDelaunay default constructor
TGraphDelaunay(TGraph2D* g)
 TGraphDelaunay normal constructor
 TGraphDelaunay destructor.
Double_t ComputeZ(Double_t x, Double_t y)
 Return the z value corresponding to the (x,y) point in fGraph2D
void CreateTrianglesDataStructure()
 Function used internally only. It creates the data structures needed to
 compute the Delaunay triangles.
Bool_t Enclose(Int_t T1, Int_t T2, Int_t T3, Int_t Ex) const
 Is point e inside the triangle t1-t2-t3 ?
void FileIt(Int_t P, Int_t N, Int_t M)
 Files the triangle defined by the 3 vertices p, n and m into the
 fxTried arrays. If these arrays are to small they are automatically
void FindAllTriangles()
 Attempt to find all the Delaunay triangles of the point set. It is not
 guaranteed that it will fully succeed, and no check is made that it has
 fully succeeded (such a check would be possible by referencing the points
 that make up the convex hull). The method is to check if each triangle
 shares all three of its sides with other triangles. If not, a point is
 generated just outside the triangle on the side(s) not shared, and a new
 triangle is found for that point. If this method is not working properly
 (many triangles are not being found) it's probably because the new points
 are too far beyond or too close to the non-shared sides. Fiddling with
 the size of the `alittlebit' parameter may help.
void FindHull()
 Finds those points which make up the convex hull of the set. If the xy
 plane were a sheet of wood, and the points were nails hammered into it
 at the respective coordinates, then if an elastic band were stretched
 over all the nails it would form the shape of the convex hull. Those
 nails in contact with it are the points that make up the hull.
Bool_t InHull(Int_t E, Int_t X) const
 Is point e inside the hull defined by all points apart from x ?
Double_t InterpolateOnPlane(Int_t TI1, Int_t TI2, Int_t TI3, Int_t E) const
 Finds the z-value at point e given that it lies
 on the plane defined by t1,t2,t3
Double_t Interpolate(Double_t x, Double_t y)
 Finds the Delaunay triangle that the point (xi,yi) sits in (if any) and
 calculate a z-value for it by linearly interpolating the z-values that
 make up that triangle.
void SetMaxIter(Int_t n = 100000)
 Defines the number of triangles tested for a Delaunay triangle
 (number of iterations) before abandoning the search
void SetMarginBinsContent(Double_t z = 0.)
 Sets the histogram bin height for points lying outside the convex hull ie:
 the bins in the margin.
TGraphDelaunay(const TGraphDelaunay& )
TGraphDelaunay& operator=(const TGraphDelaunay& )
TGraph2D * GetGraph2D() const
{return fGraph2D;}
Double_t GetMarginBinsContent() const
{return fZout;}
Int_t GetNdt() const
{return fNdt;}
Int_t * GetPTried() const
{return fPTried;}
Int_t * GetNTried() const
{return fNTried;}
Int_t * GetMTried() const
{return fMTried;}
Double_t * GetXN() const
{return fXN;}
Double_t * GetYN() const
{return fYN;}
Double_t GetXNmin() const
{return fXNmin;}
Double_t GetXNmax() const
{return fXNmax;}
Double_t GetYNmin() const
{return fYNmin;}
Double_t GetYNmax() const
{return fYNmax;}