Multidimensional histogram.
Use a THn if you really, really have to store more than three dimensions, and if a large fraction of all bins are filled. Better alternatives are
The major problem of THn is the memory use caused by n-dimensional histogramming: a THnD with 8 dimensions and 100 bins per dimension needs more than 2.5GB of RAM!
To construct a THn object you must use one of its templated, derived classes:
THnD (typedef for THnT<Double_t>): bin content held by a Double_t,
THnF (typedef for THnT<Float_t>): bin content held by a Float_t,
THnL (typedef for THnT<Long64_t>): bin content held by a Long64_t,
THnI (typedef for THnT<Int_t>): bin content held by an Int_t,
THnS (typedef for THnT<Short_t>): bin content held by a Short_t,
THnC (typedef for THnT<Char_t>): bin content held by a Char_t,
They take name and title, the number of dimensions, and for each dimension the number of bins, the minimal, and the maximal value on the dimension's axis. A TH2F h("h","h",10, 0., 10., 20, -5., 5.) would correspond to
Int_t bins[2] = {10, 20};
Double_t xmin[2] = {0., -5.};
Double_t xmax[2] = {10., 5.};
THnF hn("hn", "hn", 2, bins, xmin, xmax);
Filling
A THn is filled just like a regular histogram, using THn::Fill(x, weight), where x is a n-dimensional Double_t value. To take errors into account, Sumw2() must be called before filling the histogram. Storage is allocated when the first bin content is stored.
Projections
The dimensionality of a THn can be reduced by projecting it to 1, 2, 3, or n dimensions, which can be represented by a TH1, TH2, TH3, or a THn. See the Projection() members. To only project parts of the histogram, call
hn->GetAxis(12)->SetRange(from_bin, to_bin);
Conversion from other histogram classes
The static factory function THn::CreateHn() can be used to create a THn from a TH1, TH2, TH3, THnSparse and (for copying) even from a THn. The created THn will have compatble storage type, i.e. calling CreateHn() on a TH2F will create a THnF.
Definition at line 30 of file THn.h.
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| | ~THn () override |
| | Destruct a THn.
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| void | AddBinContent (const Int_t *idx, Double_t v=1.) |
| | Forwards to THnBase::SetBinContent().
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| void | AddBinContent (Long64_t bin, Double_t v=1.) override |
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| void | AddBinError2 (Long64_t bin, Double_t e2) override |
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| ROOT::Internal::THnBaseBinIter * | CreateIter (Bool_t respectAxisRange) const override |
| | Create an iterator over all bins. Public interface is THnIter.
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| void | FillBin (Long64_t bin, Double_t w) override |
| | Increment the bin content of "bin" by "w", return the bin index.
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| virtual const TNDArray & | GetArray () const =0 |
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| virtual TNDArray & | GetArray ()=0 |
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| Long64_t | GetBin (const char *name[]) const override |
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| Long64_t | GetBin (const char *name[], Bool_t=kTRUE) override |
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| Long64_t | GetBin (const Double_t *x) const override |
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| Long64_t | GetBin (const Double_t *x, Bool_t=kTRUE) override |
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| Long64_t | GetBin (const Int_t *idx) const override |
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| Long64_t | GetBin (const Int_t *idx, Bool_t=kTRUE) override |
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| Double_t | GetBinContent (const Int_t *idx) const |
| | Forwards to THnBase::GetBinContent() overload.
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| Double_t | GetBinContent (Long64_t bin, Int_t *idx=nullptr) const override |
| | Get the content of bin, and set its index if idx is != 0.
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| Double_t | GetBinError2 (Long64_t linidx) const override |
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| Long64_t | GetNbins () const override |
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| TClass * | IsA () const override |
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| THn * | Projection (Int_t ndim, const Int_t *dim, Option_t *option="") const |
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| TH3D * | Projection (Int_t xDim, Int_t yDim, Int_t zDim, Option_t *option="") const |
| | Forwards to THnBase::Projection().
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| TH1D * | Projection (Int_t xDim, Option_t *option="") const |
| | Forwards to THnBase::Projection().
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| TH2D * | Projection (Int_t yDim, Int_t xDim, Option_t *option="") const |
| | Forwards to THnBase::Projection().
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| THn * | Rebin (const Int_t *group) const |
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| THn * | Rebin (Int_t group) const |
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| void | Reset (Option_t *option="") override |
| | Reset the contents of a THn.
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| void | SetBinContent (const Int_t *idx, Double_t v) |
| | Forwards to THnBase::SetBinContent().
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| void | SetBinContent (Long64_t bin, Double_t v) override |
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| void | SetBinError2 (Long64_t bin, Double_t e2) override |
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| void | Streamer (TBuffer &) override |
| | Stream an object of class TObject.
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| void | StreamerNVirtual (TBuffer &ClassDef_StreamerNVirtual_b) |
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| void | Sumw2 () override |
| | Enable calculation of errors.
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| | ~THnBase () override |
| | Destruct a THnBase.
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| void | Add (const TH1 *hist, Double_t c=1.) |
| | Fill the THnBase with the bins of hist that have content or error != 0.
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| void | Add (const THnBase *h, Double_t c=1.) |
| | Add contents of h scaled by c to this histogram: this = this + c * h Note that if h has Sumw2 set, Sumw2 is automatically called for this if not already set.
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| void | AddBinContent (const Int_t *x, Double_t v=1.) |
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| void | Browse (TBrowser *b) override |
| | Browse a THnSparse: create an entry (ROOT::THnSparseBrowsable) for each dimension.
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| void | CalculateErrors (Bool_t calc=kTRUE) |
| | Calculate errors (or not if "calc" == kFALSE)
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| Double_t | ComputeIntegral () |
| | Compute integral (normalized cumulative sum of bins) w/o under/overflows The result is stored in fIntegral and used by the GetRandom functions.
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| void | Divide (const THnBase *h) |
| | Divide this histogram by h this = this/(h) Note that if h has Sumw2 set, Sumw2 is automatically called for this if not already set.
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| void | Divide (const THnBase *h1, const THnBase *h2, Double_t c1=1., Double_t c2=1., Option_t *option="") |
| | Replace contents of this histogram by multiplication of h1 by h2 this = (c1*h1)/(c2*h2) Note that if h1 or h2 have Sumw2 set, Sumw2 is automatically called for this if not already set.
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| Long64_t | Fill (const char *name[], Double_t w=1.) |
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| Long64_t | Fill (const Double_t *x, Double_t w=1.) |
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| template<typename... MoreTypes> |
| Long64_t | Fill (Double_t firstval, MoreTypes... morevals) |
| | Fill with the provided variadic arguments.
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| TFitResultPtr | Fit (TF1 *f1, Option_t *option="", Option_t *goption="") |
| | Fit a THnSparse with function f.
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| TAxis * | GetAxis (Int_t dim) const |
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| Double_t | GetBinContent (const Int_t *idx) const |
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| Double_t | GetBinError (const Int_t *idx) const |
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| Double_t | GetBinError (Long64_t linidx) const |
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| Bool_t | GetCalculateErrors () const |
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| Double_t | GetEntries () const |
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| TObjArray * | GetListOfAxes () |
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| const TObjArray * | GetListOfAxes () const |
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| TList * | GetListOfFunctions () |
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| Int_t | GetNdimensions () const |
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| void | GetRandom (Double_t *rand, Bool_t subBinRandom=kTRUE) |
| | Generate an n-dimensional random tuple based on the histogrammed distribution.
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| Double_t | GetSumw () const |
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| Double_t | GetSumw2 () const |
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| Double_t | GetSumwx (Int_t dim) const |
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| Double_t | GetSumwx2 (Int_t dim) const |
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| Double_t | GetWeightSum () const |
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| TClass * | IsA () const override |
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| Bool_t | IsFolder () const override |
| | Returns kTRUE in case object contains browsable objects (like containers or lists of other objects).
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| Bool_t | IsInRange (Int_t *coord) const |
| | Check whether bin coord is in range, as defined by TAxis::SetRange().
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| Long64_t | Merge (TCollection *list) |
| | Merge this with a list of THnBase's.
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| void | Multiply (const THnBase *h) |
| | Multiply this histogram by histogram h this = this * h Note that if h has Sumw2 set, Sumw2 is automatically called for this if not already set.
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| void | Multiply (TF1 *f, Double_t c=1.) |
| | Performs the operation: this = this*c*f1 if errors are defined, errors are also recalculated.
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| void | Print (Option_t *option="") const override |
| | Print a THnBase.
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| void | PrintBin (Int_t *coord, Option_t *options) const |
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| void | PrintBin (Long64_t idx, Option_t *options) const |
| | Print bin with linex index "idx".
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| void | PrintEntries (Long64_t from=0, Long64_t howmany=-1, Option_t *options=nullptr) const |
| | Print "howmany" entries starting at "from".
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| TH3D * | Projection (Int_t xDim, Int_t yDim, Int_t zDim, Option_t *option="") const |
| | Project all bins into a 3-dimensional histogram, keeping only axes "xDim", "yDim", and "zDim".
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| TH1D * | Projection (Int_t xDim, Option_t *option="") const |
| | Project all bins into a 1-dimensional histogram, keeping only axis "xDim".
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| TH2D * | Projection (Int_t yDim, Int_t xDim, Option_t *option="") const |
| | Project all bins into a 2-dimensional histogram, keeping only axes "xDim" and "yDim".
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| THnBase * | ProjectionND (Int_t ndim, const Int_t *dim, Option_t *option="") const |
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| void | RebinnedAdd (const THnBase *h, Double_t c=1.) |
| | Add contents of h scaled by c to this histogram: this = this + c * h Note that if h has Sumw2 set, Sumw2 is automatically called for this if not already set.
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| void | Scale (Double_t c) |
| | Scale contents and errors of this histogram by c: this = this * c It does not modify the histogram's number of entries.
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| void | SetBinContent (const Int_t *idx, Double_t v) |
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| void | SetBinEdges (Int_t idim, const Double_t *bins) |
| | Set the axis # of bins and bin limits on dimension idim.
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| void | SetBinError (const Int_t *idx, Double_t e) |
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| void | SetBinError (Long64_t bin, Double_t e) |
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| void | SetEntries (Double_t entries) |
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| void | SetTitle (const char *title) override |
| | Change (i.e.
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| void | Streamer (TBuffer &) override |
| | Stream an object of class TObject.
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| void | StreamerNVirtual (TBuffer &ClassDef_StreamerNVirtual_b) |
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| | TNamed () |
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| | TNamed (const char *name, const char *title) |
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| | TNamed (const TNamed &named) |
| | TNamed copy ctor.
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| | TNamed (const TString &name, const TString &title) |
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| virtual | ~TNamed () |
| | TNamed destructor.
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| void | Clear (Option_t *option="") override |
| | Set name and title to empty strings ("").
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| TObject * | Clone (const char *newname="") const override |
| | Make a clone of an object using the Streamer facility.
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| Int_t | Compare (const TObject *obj) const override |
| | Compare two TNamed objects.
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| void | Copy (TObject &named) const override |
| | Copy this to obj.
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| virtual void | FillBuffer (char *&buffer) |
| | Encode TNamed into output buffer.
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| const char * | GetName () const override |
| | Returns name of object.
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| const char * | GetTitle () const override |
| | Returns title of object.
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| ULong_t | Hash () const override |
| | Return hash value for this object.
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| TClass * | IsA () const override |
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| Bool_t | IsSortable () const override |
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| void | ls (Option_t *option="") const override |
| | List TNamed name and title.
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| TNamed & | operator= (const TNamed &rhs) |
| | TNamed assignment operator.
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| void | Print (Option_t *option="") const override |
| | Print TNamed name and title.
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| virtual void | SetName (const char *name) |
| | Set the name of the TNamed.
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| virtual void | SetNameTitle (const char *name, const char *title) |
| | Set all the TNamed parameters (name and title).
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| virtual Int_t | Sizeof () const |
| | Return size of the TNamed part of the TObject.
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| void | Streamer (TBuffer &) override |
| | Stream an object of class TObject.
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| void | StreamerNVirtual (TBuffer &ClassDef_StreamerNVirtual_b) |
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| | TObject () |
| | TObject constructor.
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| | TObject (const TObject &object) |
| | TObject copy ctor.
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| virtual | ~TObject () |
| | TObject destructor.
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| void | AbstractMethod (const char *method) const |
| | Use this method to implement an "abstract" method that you don't want to leave purely abstract.
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| virtual void | AppendPad (Option_t *option="") |
| | Append graphics object to current pad.
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| ULong_t | CheckedHash () |
| | Check and record whether this class has a consistent Hash/RecursiveRemove setup (*) and then return the regular Hash value for this object.
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| virtual const char * | ClassName () const |
| | Returns name of class to which the object belongs.
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| virtual void | Delete (Option_t *option="") |
| | Delete this object.
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| virtual Int_t | DistancetoPrimitive (Int_t px, Int_t py) |
| | Computes distance from point (px,py) to the object.
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| virtual void | Draw (Option_t *option="") |
| | Default Draw method for all objects.
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| virtual void | DrawClass () const |
| | Draw class inheritance tree of the class to which this object belongs.
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| virtual TObject * | DrawClone (Option_t *option="") const |
| | Draw a clone of this object in the current selected pad with: gROOT->SetSelectedPad(c1).
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| virtual void | Dump () const |
| | Dump contents of object on stdout.
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| virtual void | Error (const char *method, const char *msgfmt,...) const |
| | Issue error message.
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| virtual void | Execute (const char *method, const char *params, Int_t *error=nullptr) |
| | Execute method on this object with the given parameter string, e.g.
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| virtual void | Execute (TMethod *method, TObjArray *params, Int_t *error=nullptr) |
| | Execute method on this object with parameters stored in the TObjArray.
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| virtual void | ExecuteEvent (Int_t event, Int_t px, Int_t py) |
| | Execute action corresponding to an event at (px,py).
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| virtual void | Fatal (const char *method, const char *msgfmt,...) const |
| | Issue fatal error message.
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| virtual TObject * | FindObject (const char *name) const |
| | Must be redefined in derived classes.
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| virtual TObject * | FindObject (const TObject *obj) const |
| | Must be redefined in derived classes.
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| virtual Option_t * | GetDrawOption () const |
| | Get option used by the graphics system to draw this object.
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| virtual const char * | GetIconName () const |
| | Returns mime type name of object.
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| virtual char * | GetObjectInfo (Int_t px, Int_t py) const |
| | Returns string containing info about the object at position (px,py).
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| virtual Option_t * | GetOption () const |
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| virtual UInt_t | GetUniqueID () const |
| | Return the unique object id.
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| virtual Bool_t | HandleTimer (TTimer *timer) |
| | Execute action in response of a timer timing out.
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| Bool_t | HasInconsistentHash () const |
| | Return true is the type of this object is known to have an inconsistent setup for Hash and RecursiveRemove (i.e.
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| |
| virtual void | Info (const char *method, const char *msgfmt,...) const |
| | Issue info message.
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| |
| virtual Bool_t | InheritsFrom (const char *classname) const |
| | Returns kTRUE if object inherits from class "classname".
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| virtual Bool_t | InheritsFrom (const TClass *cl) const |
| | Returns kTRUE if object inherits from TClass cl.
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| virtual void | Inspect () const |
| | Dump contents of this object in a graphics canvas.
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| void | InvertBit (UInt_t f) |
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| Bool_t | IsDestructed () const |
| | IsDestructed.
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| |
| virtual Bool_t | IsEqual (const TObject *obj) const |
| | Default equal comparison (objects are equal if they have the same address in memory).
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| R__ALWAYS_INLINE Bool_t | IsOnHeap () const |
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| R__ALWAYS_INLINE Bool_t | IsZombie () const |
| |
| void | MayNotUse (const char *method) const |
| | Use this method to signal that a method (defined in a base class) may not be called in a derived class (in principle against good design since a child class should not provide less functionality than its parent, however, sometimes it is necessary).
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| virtual Bool_t | Notify () |
| | This method must be overridden to handle object notification (the base implementation is no-op).
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| void | Obsolete (const char *method, const char *asOfVers, const char *removedFromVers) const |
| | Use this method to declare a method obsolete.
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| void | operator delete (void *ptr) |
| | Operator delete.
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| |
| void | operator delete (void *ptr, void *vp) |
| | Only called by placement new when throwing an exception.
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| void | operator delete[] (void *ptr) |
| | Operator delete [].
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| |
| void | operator delete[] (void *ptr, void *vp) |
| | Only called by placement new[] when throwing an exception.
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| void * | operator new (size_t sz) |
| |
| void * | operator new (size_t sz, void *vp) |
| |
| void * | operator new[] (size_t sz) |
| |
| void * | operator new[] (size_t sz, void *vp) |
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| TObject & | operator= (const TObject &rhs) |
| | TObject assignment operator.
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| virtual void | Paint (Option_t *option="") |
| | This method must be overridden if a class wants to paint itself.
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| virtual void | Pop () |
| | Pop on object drawn in a pad to the top of the display list.
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| virtual Int_t | Read (const char *name) |
| | Read contents of object with specified name from the current directory.
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| virtual void | RecursiveRemove (TObject *obj) |
| | Recursively remove this object from a list.
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| void | ResetBit (UInt_t f) |
| |
| virtual void | SaveAs (const char *filename="", Option_t *option="") const |
| | Save this object in the file specified by filename.
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| virtual void | SavePrimitive (std::ostream &out, Option_t *option="") |
| | Save a primitive as a C++ statement(s) on output stream "out".
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| void | SetBit (UInt_t f) |
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| void | SetBit (UInt_t f, Bool_t set) |
| | Set or unset the user status bits as specified in f.
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| |
| virtual void | SetDrawOption (Option_t *option="") |
| | Set drawing option for object.
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| |
| virtual void | SetUniqueID (UInt_t uid) |
| | Set the unique object id.
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| |
| void | StreamerNVirtual (TBuffer &ClassDef_StreamerNVirtual_b) |
| |
| virtual void | SysError (const char *method, const char *msgfmt,...) const |
| | Issue system error message.
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| |
| R__ALWAYS_INLINE Bool_t | TestBit (UInt_t f) const |
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| Int_t | TestBits (UInt_t f) const |
| |
| virtual void | UseCurrentStyle () |
| | Set current style settings in this object This function is called when either TCanvas::UseCurrentStyle or TROOT::ForceStyle have been invoked.
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| |
| virtual void | Warning (const char *method, const char *msgfmt,...) const |
| | Issue warning message.
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| |
| virtual Int_t | Write (const char *name=nullptr, Int_t option=0, Int_t bufsize=0) |
| | Write this object to the current directory.
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| |
| virtual Int_t | Write (const char *name=nullptr, Int_t option=0, Int_t bufsize=0) const |
| | Write this object to the current directory.
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| |
|
| | THn ()=default |
| |
| | THn (const char *name, const char *title, Int_t dim, const Int_t *nbins, const Double_t *xmin, const Double_t *xmax) |
| | Construct a THn.
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| | THn (const char *name, const char *title, Int_t dim, const Int_t *nbins, const std::vector< std::vector< double > > &xbins) |
| |
| void | AllocCoordBuf () const |
| | Create the coordinate buffer.
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| |
| void | InitStorage (Int_t *nbins, Int_t chunkSize) override |
| | Initialize the storage of a histogram created via Init()
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| |
| | THnBase () |
| |
| | THnBase (const char *name, const char *title, Int_t dim, const Int_t *nbins, const Double_t *xmin, const Double_t *xmax) |
| | Construct a THnBase with "dim" dimensions, "nbins" holds the number of bins for each dimension; "xmin" and "xmax" the minimal and maximal value for each dimension.
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| | THnBase (const char *name, const char *title, Int_t dim, const Int_t *nbins, const std::vector< std::vector< double > > &xbins) |
| |
| | THnBase (const THnBase &other) |
| |
| | THnBase (THnBase &&other) |
| |
| void | AddInternal (const THnBase *h, Double_t c, Bool_t rebinned) |
| | Add() implementation for both rebinned histograms and those with identical binning.
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| |
| Bool_t | CheckConsistency (const THnBase *h, const char *tag) const |
| | Consistency check on (some of) the parameters of two histograms (for operations).
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| |
| THnBase * | CloneEmpty (const char *name, const char *title, const TObjArray *axes, Bool_t keepTargetAxis) const |
| | Create a new THnBase object that is of the same type as *this, but with dimensions and bins given by axes.
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| |
| TH1 * | CreateHist (const char *name, const char *title, const TObjArray *axes, Bool_t keepTargetAxis) const |
| | Create an empty histogram with name and title with a given set of axes.
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| |
| void | FillBinBase (Double_t w) |
| | Increment the statistics due to filled weight "w",.
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| |
| void | Init (const char *name, const char *title, const TObjArray *axes, Bool_t keepTargetAxis, Int_t chunkSize=1024 *16) |
| | Initialize axes and name.
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| |
| THnBase & | operator= (const THnBase &other) |
| |
| THnBase & | operator= (THnBase &&other) |
| |
| Bool_t | PrintBin (Long64_t idx, Int_t *coord, Option_t *options) const |
| | Print one bin.
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| |
| TObject * | ProjectionAny (Int_t ndim, const Int_t *dim, Bool_t wantNDim, Option_t *option="") const |
| | Project all bins into a ndim-dimensional THn / THnSparse (whatever *this is) or if (ndim < 4 and !wantNDim) a TH1/2/3 histogram, keeping only axes in dim (specifying ndim dimensions).
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| |
| THnBase * | RebinBase (const Int_t *group) const |
| | Combine the content of "group" neighboring bins for each dimension into a new bin and return the resulting THnBase.
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| |
| THnBase * | RebinBase (Int_t group) const |
| | Combine the content of "group" neighboring bins into a new bin and return the resulting THnBase.
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| |
| virtual void | Reserve (Long64_t) |
| |
| void | ResetBase (Option_t *option="") |
| | Clear the histogram.
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| |
| virtual void | SetFilledBins (Long64_t) |
| |
| void | UpdateXStat (const Double_t *x, Double_t w=1.) |
| |
| virtual void | DoError (int level, const char *location, const char *fmt, va_list va) const |
| | Interface to ErrorHandler (protected).
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| |
| void | MakeZombie () |
| |
Public Member Functions inherited from THnBase
