[u/mrichter/AliRoot.git] / TPC / AliTPCHuffman.cxx

/**************************************************************************
 * Copyright(c) 1998-2003, ALICE Experiment at CERN, All rights reserved. *
 *                                                                        *
 * Author: The ALICE Off-line Project.                                    *
 * Contributors are mentioned in the code where appropriate.              *
 *                                                                        *
 * Permission to use, copy, modify and distribute this software and its   *
 * documentation strictly for non-commercial purposes is hereby granted   *
 * without fee, provided that the above copyright notice appears in all   *
 * copies and that both the copyright notice and this permission notice   *
 * appear in the supporting documentation. The authors make no claims     *
 * about the suitability of this software for any purpose. It is          *
 * provided "as is" without express or implied warranty.                  *
 **************************************************************************/
/* $Id:*/
////////////////////////////////////////////////
//  Huffman classes for set:TPC               //
////////////////////////////////////////////////
//This file contains two classes and it implements 
//the Huffman algorithm for creating tables
//used in the compression phase.
//The class AliTPCHNode represents a node of the Huffman tree, while
//the class AliTPCHTable represents a compression table

#include <TObjArray.h>
#include <Riostream.h>
#include <TMath.h>
#include "AliTPCBuffer160.h"
#include "AliTPCHuffman.h"

ClassImp(AliTPCHNode)

AliTPCHNode::AliTPCHNode(){
  //Constructor
  fLeft=0;
  fRight=0;
}

//////////////////////////////////////////////////////////////////////////////

AliTPCHNode::AliTPCHNode(Int_t sym, Double_t freq){
  //Standard constructor
  fSymbol=sym;
  fFrequency=freq;
  fLeft=0;
  fRight=0;
}

//////////////////////////////////////////////////////////////////////////////

AliTPCHNode::AliTPCHNode(const AliTPCHNode &source){
  //Copy Constructor 
  if(&source == this) return;
  this->fSymbol = source.fSymbol;
  this->fFrequency = source.fFrequency;
  this->fLeft = source.fLeft;
  this->fRight = source.fRight;
  return;
}

//////////////////////////////////////////////////////////////////////////////

AliTPCHNode& AliTPCHNode::operator=(const AliTPCHNode &source){
  //Assignment operator
  if(&source == this) return *this;
  this->fSymbol = source.fSymbol;
  this->fFrequency = source.fFrequency;
  this->fLeft = source.fLeft;
  this->fRight = source.fRight;
  return *this;
}

//////////////////////////////////////////////////////////////////////////////

Int_t AliTPCHNode::Compare(const TObject *obj)const{
  //Function called by Sort method of TObjArray
  AliTPCHNode *node=(AliTPCHNode *)obj;
  Double_t f=fFrequency;
  Double_t fo=node->fFrequency;
  if (f<fo) return 1;
  else if (f>fo) return -1;
  else return 0;
}

//////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////

ClassImp(AliTPCHTable)
  
AliTPCHTable::AliTPCHTable(){
  //Constructor
  fCodeLen=0;
  fCode=0;
  fHNodes=0;
  fNnodes=0;
  fNum=0;
  fVerbose=0;
}

//////////////////////////////////////////////////////////////////////////////

AliTPCHTable::AliTPCHTable(Int_t size){
  //Initialization
  fSize=size;
  fCodeLen = new UChar_t[fSize]; 
  fCode = new Double_t[fSize]; 
  fHNodes = new TObjArray;
  fNnodes=0;
  fNum=0;
  fVerbose=0;
  fSym= new Short_t[fSize];
  for (Short_t i=0;i<fSize;i++) {
    fSym[i]=i;
  }//end for
  ClearTable(); 
}

//////////////////////////////////////////////////////////////////////////////

AliTPCHTable::AliTPCHTable(const AliTPCHTable &source){
  //Copy Constructor 
  if(&source == this) return;
  this->fSize = source.fSize;
  this->fCodeLen = source.fCodeLen;
  this->fCode = source.fCode;
  this->fSym = source.fSym;
  this->fHNodes = source.fHNodes;
  this->fNnodes = source.fNnodes;
  this->fNum=source.fNum;
  this->fVerbose=source.fVerbose;
  return;
}

//////////////////////////////////////////////////////////////////////////////

AliTPCHTable& AliTPCHTable::operator=(const AliTPCHTable &source) {
  //Assignment operator
  if(&source == this) return *this;
  this->fSize = source.fSize;
  this->fCodeLen = source.fCodeLen;
  this->fCode = source.fCode;
  this->fSym = source.fSym;
  this->fHNodes = source.fHNodes;
  this->fNnodes = source.fNnodes;
  this->fNum=source.fNum;
  this->fVerbose=source.fVerbose;
  return *this;
}

//////////////////////////////////////////////////////////////////////////////

AliTPCHTable::~AliTPCHTable(){
  //HTable destructor
  if(fVerbose)
    cout<<"HTable destructor !\n";
  if (fCodeLen) delete[] fCodeLen;
  if (fCode) delete [] fCode;
  if (fHNodes) {
    fHNodes->Delete(); //Clear out the collection and deletes the removed objects
    delete fHNodes;
  }//end if
}

//////////////////////////////////////////////////////////////////////////////

void AliTPCHTable::SetCodeLen(UChar_t len,Int_t val){
  //Sets codelength of "val" to the variable "len"
  fCodeLen[val]=len;
  return;
}

//////////////////////////////////////////////////////////////////////////////

void AliTPCHTable::SetCode(Double_t code,Int_t val){
  //Sets the binary code of the variable "val"
  fCode[val]=code;
  return;
}

//////////////////////////////////////////////////////////////////////////////

void AliTPCHTable::PrintTable()const{
  //This method prints a table
  cout<<"Table for Huffman coding\n";
  cout<<"  Symbol|   Code   |   Length \n";
  for (Int_t i=0;i<fSize;i++){
    if (fCodeLen[i]){
      cout.width(6);cout<<fSym[i];
      cout.width(3);cout<<"|";
      cout.width(6);cout<<hex<<(ULong_t)fCode[i]<<dec;
      cout.width(5);cout<<"|";
      cout.width(6);cout<<(ULong_t)fCodeLen[i]<<endl;  
    }//end if
  }//end for
}

//////////////////////////////////////////////////////////////////////////////

Bool_t AliTPCHTable::SpanTree(AliTPCHNode *start, ULong_t code, UChar_t len){
  //Hoffman codes are generated spanning the Huffman tree
  //In an Huffman tree any internal node has always two children
  AliTPCHNode * visited;
  visited = start;
  Int_t idx=visited->GetSymbol();
  if (!visited->GetLeft()) {
    fCode[idx] = code; 
    fCodeLen[idx] = len;
    return kTRUE;
  }//end if
  SpanTree(visited->GetLeft(), code << 1, len + 1);
  SpanTree(visited->GetRight(), code << 1 | 0x0001, len + 1);
  return kTRUE;
}

//////////////////////////////////////////////////////////////////////////////

void AliTPCHTable::ResetHNodes(){
  //Reset number of HNodes and the HNodes array 
  if (fHNodes)  fHNodes->Clear();
  if (fNnodes)  fNnodes=0;
}

//////////////////////////////////////////////////////////////////////////////

void AliTPCHTable::ClearTable(){
  //Clear the table
  memset(fCodeLen,0,sizeof(UChar_t)*fSize);
  memset(fCode,0,sizeof(Double_t)*fSize);
}

//////////////////////////////////////////////////////////////////////////////

Int_t  AliTPCHTable::GetFrequencies(const char *fname){
  //It fills the "fCode" array with the frequencies of the symbols read from the file
  AliTPCBuffer160 buff(fname,0);
  ULong_t numberOfWords=0;
  Int_t val;
  while((val=buff.GetNext())!=-1){
    fCode[val]++;
    fNum++;
    numberOfWords++;
  }
  cout<<"Total number of words: "<<numberOfWords<<endl;
  //Print out the frequencies 
  /*
    for (Int_t i=0;i<fSize;i++){
    if (fCode[i])cout<<"Symbol: "<<i<<" Freq: "<<fCode[i]<<endl;
    }
    cout<<endl;
  */
  return 0;
}

Int_t AliTPCHTable::SetValFrequency(const Int_t Val,Double_t Value){
  //This method sets to "Value" the frequency of the symbol "Val"
  fCode[Val]=Value;
  fNum=1;
  return 0;
}

//////////////////////////////////////////////////////////////////////////////

Int_t AliTPCHTable::SetFrequency(const Int_t Val){
  //It increments by one the frequency of the symbol "Val" whose frequency is 
  //stored in the fCode array
  fCode[Val]++;
  fNum++;
  return 0;
}

//////////////////////////////////////////////////////////////////////////////

Int_t AliTPCHTable::NormalizeFrequencies(){
  //This method normalized the frequencies
  //Frequencies normalization
  Double_t sum=0.;
  for (Int_t i=0; i< fSize; i++) {
    sum+=fCode[i];
  }//end for 
  if (fVerbose){
    cout<<"Frequency sum: "<<sum<<endl;
  }//end if
  if(sum!=0.){
    for (Int_t i=0; i< fSize; i++) {
      fCode[i]/=sum;
      if ((fCode[i]!=0.) && (fCode[i]<10e-20))cout<<"Frequency value very small !!! "<<fCode[i]<<endl;
    }//end for 
  }
  return 0;
}
//////////////////////////////////////////////////////////////////////////////
Int_t AliTPCHTable::StoreFrequencies(const char *fname)const{
  //It stores the frequencies in a text file
  ofstream ftxt(fname);  
  for (Int_t i=0;i<fSize;i++){
    ftxt<<fCode[i]<<endl;
  }
  ftxt.close();
  return 0;
}

//////////////////////////////////////////////////////////////////////////////

void AliTPCHTable::CompleteTable(Int_t k){
  //According to the kind of table (0..4) it associates a dummy frequency (1) to 
  //every symbols whose real frequency is zero, in a given range 0..max
  Int_t max;
  ULong_t val;
  switch(k){
  case 0:
    max=fSize;
    val=1;
    break;
  case 1:
    max=445;
    val=1;
    break;
  default:
    max=fSize;
    val=1;
    break;
  }//end switch

  for(Int_t i=0;i<max;i++){
    if(fCode[i]==0.0)fCode[i]=val;
  }
  return;
}

//////////////////////////////////////////////////////////////////////////////

Double_t  AliTPCHTable::GetEntropy()const{
  //This method calculates the value of the entropy 
  Double_t entropy=0;
  Double_t prob=0;
  for (Int_t i=0;i<fSize;i++){
    if (fCode[i]){
      prob=fCode[i]/(Double_t)fNum;
      entropy+=prob*(TMath::Log2(prob));
    }
  }
  return -entropy;
}

//////////////////////////////////////////////////////////////////////////////

Int_t AliTPCHTable::BuildHTable(){
  //It builds a Huffman tree 
  if(GetWordsNumber()){
    for (Int_t i=0; i< fSize; i++) {
      if (fCode[i] > 0.){
	fNnodes++;
	//cout<< "Symbol:"<<i<<" Freq:"<<fCode[i]<<endl;
	fHNodes->Add(new AliTPCHNode(i,fCode[i]));
      }//end if
    }//end for
    Int_t nentries=fHNodes->GetEntriesFast();  
    //cout<<"Number of symbols: "<<nentries<<endl;
    Int_t nindex=nentries-1;  
    while (nindex > 0){
      fHNodes->Sort(nindex+1);
      AliTPCHNode *aux = new AliTPCHNode(0,0);
      AliTPCHNode *node= (AliTPCHNode*)fHNodes->UncheckedAt(nindex-1);
      AliTPCHNode *node1= (AliTPCHNode*)fHNodes->UncheckedAt(nindex);
      
      aux->SetLeft(node);
      aux->SetRight(node1);
      aux->SetFrequency(node->GetFrequency() + node1->GetFrequency());
      fHNodes->RemoveAt(nindex-1);
      fHNodes->AddAt(aux,nindex-1);
      nindex--;
    }//end while
    ClearTable();  
    AliTPCHNode *start= (AliTPCHNode*)fHNodes->UncheckedAt(0);
    SpanTree(start,0,0);
  }//end if
  else{
    cout<<"Table contains 0 elements\n";
  }//end else
  return 0;
}
//////////////////////////////////////////////////////////////////////////////
Commit	Line	Data
2e9f335b	1	/**************************************************************************
	2	* Copyright(c) 1998-2003, ALICE Experiment at CERN, All rights reserved. *
	3	* *
	4	* Author: The ALICE Off-line Project. *
	5	* Contributors are mentioned in the code where appropriate. *
	6	* *
	7	* Permission to use, copy, modify and distribute this software and its *
	8	* documentation strictly for non-commercial purposes is hereby granted *
	9	* without fee, provided that the above copyright notice appears in all *
	10	* copies and that both the copyright notice and this permission notice *
	11	* appear in the supporting documentation. The authors make no claims *
	12	* about the suitability of this software for any purpose. It is *
	13	* provided "as is" without express or implied warranty. *
	14	**************************************************************************/
a79660fb	15	/* $Id:*/
2e9f335b	16	////////////////////////////////////////////////
	17	// Huffman classes for set:TPC //
	18	////////////////////////////////////////////////
a79660fb	19	//This file contains two classes and it implements
	20	//the Huffman algorithm for creating tables
	21	//used in the compression phase.
	22	//The class AliTPCHNode represents a node of the Huffman tree, while
	23	//the class AliTPCHTable represents a compression table
	24
2e9f335b	25	#include <TObjArray.h>
b62e2a95	26	#include <Riostream.h>
b62e2a95	27	#include <TMath.h>
2e9f335b	28	#include "AliTPCBuffer160.h"
b62e2a95	29	#include "AliTPCHuffman.h"
2e9f335b	30
	31	ClassImp(AliTPCHNode)
	32
	33	AliTPCHNode::AliTPCHNode(){
a79660fb	34	//Constructor
2e9f335b	35	fLeft=0;
	36	fRight=0;
	37	}
	38
	39	//////////////////////////////////////////////////////////////////////////////
	40
	41	AliTPCHNode::AliTPCHNode(Int_t sym, Double_t freq){
a79660fb	42	//Standard constructor
2e9f335b	43	fSymbol=sym;
	44	fFrequency=freq;
	45	fLeft=0;
	46	fRight=0;
	47	}
	48
	49	//////////////////////////////////////////////////////////////////////////////
	50
	51	AliTPCHNode::AliTPCHNode(const AliTPCHNode &source){
a79660fb	52	//Copy Constructor
2e9f335b	53	if(&source == this) return;
	54	this->fSymbol = source.fSymbol;
	55	this->fFrequency = source.fFrequency;
	56	this->fLeft = source.fLeft;
	57	this->fRight = source.fRight;
	58	return;
	59	}
	60
	61	//////////////////////////////////////////////////////////////////////////////
	62
	63	AliTPCHNode& AliTPCHNode::operator=(const AliTPCHNode &source){
a79660fb	64	//Assignment operator
2e9f335b	65	if(&source == this) return *this;
	66	this->fSymbol = source.fSymbol;
	67	this->fFrequency = source.fFrequency;
	68	this->fLeft = source.fLeft;
	69	this->fRight = source.fRight;
	70	return *this;
	71	}
	72
	73	//////////////////////////////////////////////////////////////////////////////
	74
	75	Int_t AliTPCHNode::Compare(const TObject *obj)const{
a79660fb	76	//Function called by Sort method of TObjArray
2e9f335b	77	AliTPCHNode node=(AliTPCHNode )obj;
	78	Double_t f=fFrequency;
	79	Double_t fo=node->fFrequency;
	80	if (f<fo) return 1;
	81	else if (f>fo) return -1;
	82	else return 0;
	83	}
	84
	85	//////////////////////////////////////////////////////////////////////////////
	86	//////////////////////////////////////////////////////////////////////////////
	87	//////////////////////////////////////////////////////////////////////////////
	88
	89	ClassImp(AliTPCHTable)
	90
	91	AliTPCHTable::AliTPCHTable(){
a79660fb	92	//Constructor
2e9f335b	93	fCodeLen=0;
	94	fCode=0;
	95	fHNodes=0;
	96	fNnodes=0;
	97	fNum=0;
	98	fVerbose=0;
	99	}
	100
	101	//////////////////////////////////////////////////////////////////////////////
	102
	103	AliTPCHTable::AliTPCHTable(Int_t size){
a79660fb	104	//Initialization
2e9f335b	105	fSize=size;
	106	fCodeLen = new UChar_t[fSize];
	107	fCode = new Double_t[fSize];
	108	fHNodes = new TObjArray;
	109	fNnodes=0;
	110	fNum=0;
	111	fVerbose=0;
	112	fSym= new Short_t[fSize];
	113	for (Short_t i=0;i<fSize;i++) {
	114	fSym[i]=i;
	115	}//end for
	116	ClearTable();
	117	}
	118
	119	//////////////////////////////////////////////////////////////////////////////
	120
	121	AliTPCHTable::AliTPCHTable(const AliTPCHTable &source){
a79660fb	122	//Copy Constructor
2e9f335b	123	if(&source == this) return;
	124	this->fSize = source.fSize;
	125	this->fCodeLen = source.fCodeLen;
	126	this->fCode = source.fCode;
	127	this->fSym = source.fSym;
	128	this->fHNodes = source.fHNodes;
	129	this->fNnodes = source.fNnodes;
	130	this->fNum=source.fNum;
	131	this->fVerbose=source.fVerbose;
	132	return;
	133	}
	134
	135	//////////////////////////////////////////////////////////////////////////////
	136
	137	AliTPCHTable& AliTPCHTable::operator=(const AliTPCHTable &source) {
a79660fb	138	//Assignment operator
2e9f335b	139	if(&source == this) return *this;
	140	this->fSize = source.fSize;
	141	this->fCodeLen = source.fCodeLen;
	142	this->fCode = source.fCode;
	143	this->fSym = source.fSym;
	144	this->fHNodes = source.fHNodes;
	145	this->fNnodes = source.fNnodes;
	146	this->fNum=source.fNum;
	147	this->fVerbose=source.fVerbose;
	148	return *this;
	149	}
	150
	151	//////////////////////////////////////////////////////////////////////////////
	152
	153	AliTPCHTable::~AliTPCHTable(){
a79660fb	154	//HTable destructor
2e9f335b	155	if(fVerbose)
	156	cout<<"HTable destructor !\n";
	157	if (fCodeLen) delete[] fCodeLen;
	158	if (fCode) delete [] fCode;
	159	if (fHNodes) {
	160	fHNodes->Delete(); //Clear out the collection and deletes the removed objects
	161	delete fHNodes;
	162	}//end if
	163	}
	164
	165	//////////////////////////////////////////////////////////////////////////////
	166
	167	void AliTPCHTable::SetCodeLen(UChar_t len,Int_t val){
a79660fb	168	//Sets codelength of "val" to the variable "len"
2e9f335b	169	fCodeLen[val]=len;
	170	return;
	171	}
	172
	173	//////////////////////////////////////////////////////////////////////////////
	174
	175	void AliTPCHTable::SetCode(Double_t code,Int_t val){
a79660fb	176	//Sets the binary code of the variable "val"
2e9f335b	177	fCode[val]=code;
	178	return;
	179	}
	180
	181	//////////////////////////////////////////////////////////////////////////////
	182
	183	void AliTPCHTable::PrintTable()const{
a79660fb	184	//This method prints a table
2e9f335b	185	cout<<"Table for Huffman coding\n";
	186	cout<<" Symbol\| Code \| Length \n";
	187	for (Int_t i=0;i<fSize;i++){
	188	if (fCodeLen[i]){
	189	cout.width(6);cout<<fSym[i];
	190	cout.width(3);cout<<"\|";
	191	cout.width(6);cout<<hex<<(ULong_t)fCode[i]<<dec;
	192	cout.width(5);cout<<"\|";
	193	cout.width(6);cout<<(ULong_t)fCodeLen[i]<<endl;
	194	}//end if
	195	}//end for
	196	}
	197
	198	//////////////////////////////////////////////////////////////////////////////
	199
	200	Bool_t AliTPCHTable::SpanTree(AliTPCHNode *start, ULong_t code, UChar_t len){
a79660fb	201	//Hoffman codes are generated spanning the Huffman tree
2e9f335b	202	//In an Huffman tree any internal node has always two children
	203	AliTPCHNode * visited;
	204	visited = start;
	205	Int_t idx=visited->GetSymbol();
	206	if (!visited->GetLeft()) {
	207	fCode[idx] = code;
	208	fCodeLen[idx] = len;
	209	return kTRUE;
	210	}//end if
	211	SpanTree(visited->GetLeft(), code << 1, len + 1);
	212	SpanTree(visited->GetRight(), code << 1 \| 0x0001, len + 1);
	213	return kTRUE;
	214	}
	215
	216	//////////////////////////////////////////////////////////////////////////////
	217
	218	void AliTPCHTable::ResetHNodes(){
a79660fb	219	//Reset number of HNodes and the HNodes array
2e9f335b	220	if (fHNodes) fHNodes->Clear();
	221	if (fNnodes) fNnodes=0;
	222	}
	223
	224	//////////////////////////////////////////////////////////////////////////////
	225
	226	void AliTPCHTable::ClearTable(){
a79660fb	227	//Clear the table
2e9f335b	228	memset(fCodeLen,0,sizeof(UChar_t)*fSize);
	229	memset(fCode,0,sizeof(Double_t)*fSize);
	230	}
	231
	232	//////////////////////////////////////////////////////////////////////////////
	233
	234	Int_t AliTPCHTable::GetFrequencies(const char *fname){
a79660fb	235	//It fills the "fCode" array with the frequencies of the symbols read from the file
2e9f335b	236	AliTPCBuffer160 buff(fname,0);
a79660fb	237	ULong_t numberOfWords=0;
	238	Int_t val;
	239	while((val=buff.GetNext())!=-1){
	240	fCode[val]++;
2e9f335b	241	fNum++;
a79660fb	242	numberOfWords++;
2e9f335b	243	}
a79660fb	244	cout<<"Total number of words: "<<numberOfWords<<endl;
2e9f335b	245	//Print out the frequencies
	246	/*
	247	for (Int_t i=0;i<fSize;i++){
	248	if (fCode[i])cout<<"Symbol: "<<i<<" Freq: "<<fCode[i]<<endl;
	249	}
	250	cout<<endl;
	251	*/
	252	return 0;
	253	}
	254
	255	Int_t AliTPCHTable::SetValFrequency(const Int_t Val,Double_t Value){
a79660fb	256	//This method sets to "Value" the frequency of the symbol "Val"
2e9f335b	257	fCode[Val]=Value;
	258	fNum=1;
	259	return 0;
	260	}
	261
	262	//////////////////////////////////////////////////////////////////////////////
	263
	264	Int_t AliTPCHTable::SetFrequency(const Int_t Val){
a79660fb	265	//It increments by one the frequency of the symbol "Val" whose frequency is
a79660fb	266	//stored in the fCode array
2e9f335b	267	fCode[Val]++;
	268	fNum++;
	269	return 0;
	270	}
	271
	272	//////////////////////////////////////////////////////////////////////////////
	273
9f992f70	274	Int_t AliTPCHTable::NormalizeFrequencies(){
	275	//This method normalized the frequencies
	276	//Frequencies normalization
	277	Double_t sum=0.;
	278	for (Int_t i=0; i< fSize; i++) {
	279	sum+=fCode[i];
	280	}//end for
	281	if (fVerbose){
	282	cout<<"Frequency sum: "<<sum<<endl;
	283	}//end if
	284	if(sum!=0.){
	285	for (Int_t i=0; i< fSize; i++) {
	286	fCode[i]/=sum;
	287	if ((fCode[i]!=0.) && (fCode[i]<10e-20))cout<<"Frequency value very small !!! "<<fCode[i]<<endl;
	288	}//end for
	289	}
	290	return 0;
	291	}
	292	//////////////////////////////////////////////////////////////////////////////
a79660fb	293	Int_t AliTPCHTable::StoreFrequencies(const char *fname)const{
a79660fb	294	//It stores the frequencies in a text file
2e9f335b	295	ofstream ftxt(fname);
2e9f335b	296	for (Int_t i=0;i<fSize;i++){
9f992f70	297	ftxt<<fCode[i]<<endl;
2e9f335b	298	}
	299	ftxt.close();
	300	return 0;
	301	}
	302
	303	//////////////////////////////////////////////////////////////////////////////
	304
	305	void AliTPCHTable::CompleteTable(Int_t k){
a79660fb	306	//According to the kind of table (0..4) it associates a dummy frequency (1) to
a79660fb	307	//every symbols whose real frequency is zero, in a given range 0..max
2e9f335b	308	Int_t max;
	309	ULong_t val;
	310	switch(k){
	311	case 0:
c9bd9d3d	312	max=fSize;
2e9f335b	313	val=1;
	314	break;
	315	case 1:
	316	max=445;
	317	val=1;
	318	break;
	319	default:
	320	max=fSize;
	321	val=1;
	322	break;
	323	}//end switch
	324
	325	for(Int_t i=0;i<max;i++){
	326	if(fCode[i]==0.0)fCode[i]=val;
	327	}
	328	return;
	329	}
	330
	331	//////////////////////////////////////////////////////////////////////////////
	332
	333	Double_t AliTPCHTable::GetEntropy()const{
a79660fb	334	//This method calculates the value of the entropy
2e9f335b	335	Double_t entropy=0;
	336	Double_t prob=0;
	337	for (Int_t i=0;i<fSize;i++){
	338	if (fCode[i]){
	339	prob=fCode[i]/(Double_t)fNum;
	340	entropy+=prob*(TMath::Log2(prob));
	341	}
	342	}
	343	return -entropy;
	344	}
	345
	346	//////////////////////////////////////////////////////////////////////////////
	347
	348	Int_t AliTPCHTable::BuildHTable(){
a79660fb	349	//It builds a Huffman tree
2e9f335b	350	if(GetWordsNumber()){
	351	for (Int_t i=0; i< fSize; i++) {
	352	if (fCode[i] > 0.){
	353	fNnodes++;
	354	//cout<< "Symbol:"<<i<<" Freq:"<<fCode[i]<<endl;
	355	fHNodes->Add(new AliTPCHNode(i,fCode[i]));
	356	}//end if
	357	}//end for
	358	Int_t nentries=fHNodes->GetEntriesFast();
	359	//cout<<"Number of symbols: "<<nentries<<endl;
	360	Int_t nindex=nentries-1;
	361	while (nindex > 0){
	362	fHNodes->Sort(nindex+1);
	363	AliTPCHNode *aux = new AliTPCHNode(0,0);
	364	AliTPCHNode node= (AliTPCHNode)fHNodes->UncheckedAt(nindex-1);
	365	AliTPCHNode node1= (AliTPCHNode)fHNodes->UncheckedAt(nindex);
	366
	367	aux->SetLeft(node);
	368	aux->SetRight(node1);
	369	aux->SetFrequency(node->GetFrequency() + node1->GetFrequency());
	370	fHNodes->RemoveAt(nindex-1);
	371	fHNodes->AddAt(aux,nindex-1);
	372	nindex--;
	373	}//end while
	374	ClearTable();
	375	AliTPCHNode start= (AliTPCHNode)fHNodes->UncheckedAt(0);
	376	SpanTree(start,0,0);
	377	}//end if
	378	else{
	379	cout<<"Table contains 0 elements\n";
	380	}//end else
	381	return 0;
	382	}
2e9f335b	383	//////////////////////////////////////////////////////////////////////////////