[u/mrichter/AliRoot.git] / STEER / AliStrLine.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.                  *
 **************************************************************************/
///////////////////////////////////////////////////////////////////
//                                                               //
// A straight line is coded as a point (3 Double_t) and           //
// 3 direction cosines                                           //
//                                                               //
///////////////////////////////////////////////////////////////////
#include <Riostream.h>
#include <TTree.h>
#include "AliStrLine.h"

ClassImp(AliStrLine)

//________________________________________________________
AliStrLine::AliStrLine() {
  // Default constructor
  for(Int_t i=0;i<3;i++) {
    fP0[i] = 0.;
    fCd[i] = 0.;
  }
  fTpar = 0.;
  SetDebug();
}

//________________________________________________________
AliStrLine::AliStrLine(Double_t *point, Double_t *cd) {
  // Standard constructor
  Double_t norm = 0.;
  for(Int_t i=0;i<3;i++)norm+=cd[i]*cd[i];
  if(norm) {
    norm = TMath::Sqrt(norm);
    for(Int_t i=0;i<3;i++) cd[i]/=norm;
  }
  else {
    Error("AliStrLine","Null direction cosines!!!");
  }
  SetP0(point);
  SetCd(cd);
  fTpar = 0.;
  SetDebug();
}

//________________________________________________________
AliStrLine::~AliStrLine() {
  // destructor
}

//________________________________________________________
void AliStrLine::PrintStatus() const {
  // Print current status
  cout <<"=======================================================\n";
  cout <<"Direction cosines: ";
  for(Int_t i=0;i<3;i++)cout <<fCd[i]<<"; ";
  cout <<endl;
  cout <<"Known point: ";
  for(Int_t i=0;i<3;i++)cout <<fP0[i]<<"; ";
  cout <<endl;
  cout <<"Current value for the parameter: "<<fTpar<<endl;
  cout <<" Debug flag: "<<fDebug<<endl;
}

//________________________________________________________
Int_t AliStrLine::IsParallelTo(AliStrLine *line) const {
  // returns 1 if lines are parallel, 0 if not paralel
  Double_t cd2[3];
  line->GetCd(cd2);
  Double_t vecpx=fCd[1]*cd2[2]-fCd[2]*cd2[1];
  if(vecpx!=0) return 0;
  Double_t vecpy=-fCd[0]*cd2[2]+fCd[2]*cd2[0];
  if(vecpy!=0) return 0;
  Double_t vecpz=fCd[0]*cd2[1]-fCd[1]*cd2[0];
  if(vecpz!=0) return 0;
  return 1;
}
//________________________________________________________
Int_t AliStrLine::Crossrphi(AliStrLine *line){
  // Cross 2 lines in the X-Y plane
  Double_t p2[3];
  Double_t cd2[3];
  line->GetP0(p2);
  line->GetCd(cd2);
  Double_t a=fCd[0];
  Double_t b=-cd2[0];
  Double_t c=p2[0]-fP0[0];
  Double_t d=fCd[1];
  Double_t e=-cd2[1];
  Double_t f=p2[1]-fP0[1];
  Double_t deno = a*e-b*d;
  Int_t retcode = 0;
  if(deno != 0.) {
    fTpar = (c*e-b*f)/deno;
  }
  else {
    retcode = -1;
  }
  return retcode;
}

//________________________________________________________
Int_t AliStrLine::CrossPoints(AliStrLine *line, Double_t *point1, Double_t *point2){
  // Looks for the crossing point estimated starting from the
  // DCA segment
  Double_t p2[3];
  Double_t cd2[3];
  line->GetP0(p2);
  line->GetCd(cd2);
  Int_t i;
  Double_t k1 = 0;
  for(i=0;i<3;i++)k1+=(fP0[i]-p2[i])*fCd[i];
  Double_t k2 = 0;
  for(i=0;i<3;i++)k2+=(fP0[i]-p2[i])*cd2[i];
  Double_t a11 = 0;
  for(i=0;i<3;i++)a11+=fCd[i]*cd2[i];
  Double_t a22 = -a11;
  Double_t a21 = 0;
  for(i=0;i<3;i++)a21+=cd2[i]*cd2[i];
  Double_t a12 = 0;
  for(i=0;i<3;i++)a12-=fCd[i]*fCd[i];
  Double_t deno = a11*a22-a21*a12;
  if(deno == 0.) return -1;
  fTpar = (a11*k2-a21*k1) / deno;
  Double_t par2 = (k1*a22-k2*a12) / deno;
  line->SetPar(par2);
  GetCurrentPoint(point1);
  line->GetCurrentPoint(point2);
  return 0;
}
//________________________________________________________________
Int_t AliStrLine::Cross(AliStrLine *line, Double_t *point){

  //Finds intersection between lines
  Double_t point1[3];
  Double_t point2[3];
  Int_t retcod=CrossPoints(line,point1,point2);
  if(retcod==0){
    for(Int_t i=0;i<3;i++)point[i]=(point1[i]+point2[i])/2.;
    return 0;
  }else{
    return -1;
  }
}

//___________________________________________________________
Double_t AliStrLine::GetDCA(AliStrLine *line){
  //Returns the distance of closest approach between two lines
  Double_t p2[3];
  Double_t cd2[3];
  line->GetP0(p2);
  line->GetCd(cd2);
  Int_t i;
  Int_t ispar=IsParallelTo(line);
  if(ispar){
    Double_t dist1q=0,dist2=0,mod=0;
    for(i=0;i<3;i++){
      dist1q+=(fP0[i]-p2[i])*(fP0[i]-p2[i]);
      dist2+=(fP0[i]-p2[i])*fCd[i];
      mod+=fCd[i]*fCd[i];
    }
    if(mod!=0){
      dist2/=mod;
      return TMath::Sqrt(dist1q-dist2*dist2);
    }else{return -1;}
  }else{
     Double_t perp[3];
     perp[0]=fCd[1]*cd2[2]-fCd[2]*cd2[1];
     perp[1]=-fCd[0]*cd2[2]+fCd[2]*cd2[0];
     perp[2]=fCd[0]*cd2[1]-fCd[1]*cd2[0];
     Double_t mod=0,dist=0;
     for(i=0;i<3;i++){
       mod+=perp[i]*perp[i];
       dist+=(fP0[i]-p2[i])*perp[i];
     }
     mod=sqrt(mod);
     if(mod!=0){
       dist/=mod;
       return TMath::Abs(dist);
     }else{return -1;}
  }
}
//________________________________________________________
void AliStrLine::GetCurrentPoint(Double_t *point) const {
  // Fills the array point with the current value on the line
  for(Int_t i=0;i<3;i++)point[i]=fP0[i]+fCd[i]*fTpar;
}
Commit	Line	Data
edc97986	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	**************************************************************************/
	15	///////////////////////////////////////////////////////////////////
	16	// //
	17	// A straight line is coded as a point (3 Double_t) and //
	18	// 3 direction cosines //
	19	// //
	20	///////////////////////////////////////////////////////////////////
	21	#include <Riostream.h>
	22	#include <TTree.h>
	23	#include "AliStrLine.h"
	24
	25	ClassImp(AliStrLine)
	26
	27	//________________________________________________________
	28	AliStrLine::AliStrLine() {
	29	// Default constructor
	30	for(Int_t i=0;i<3;i++) {
	31	fP0[i] = 0.;
	32	fCd[i] = 0.;
	33	}
	34	fTpar = 0.;
	35	SetDebug();
	36	}
	37
	38	//________________________________________________________
	39	AliStrLine::AliStrLine(Double_t point, Double_t cd) {
	40	// Standard constructor
	41	Double_t norm = 0.;
	42	for(Int_t i=0;i<3;i++)norm+=cd[i]*cd[i];
	43	if(norm) {
	44	norm = TMath::Sqrt(norm);
	45	for(Int_t i=0;i<3;i++) cd[i]/=norm;
	46	}
	47	else {
	48	Error("AliStrLine","Null direction cosines!!!");
	49	}
	50	SetP0(point);
	51	SetCd(cd);
	52	fTpar = 0.;
	53	SetDebug();
	54	}
	55
	56	//________________________________________________________
	57	AliStrLine::~AliStrLine() {
	58	// destructor
	59	}
	60
	61	//________________________________________________________
	62	void AliStrLine::PrintStatus() const {
	63	// Print current status
	64	cout <<"=======================================================\n";
65	cout <<"Direction cosines: ";
66	for(Int_t i=0;i<3;i++)cout <<fCd[i]<<"; ";
67	cout <<endl;
68	cout <<"Known point: ";
69	for(Int_t i=0;i<3;i++)cout <<fP0[i]<<"; ";
70	cout <<endl;
71	cout <<"Current value for the parameter: "<<fTpar<<endl;
72	cout <<" Debug flag: "<<fDebug<<endl;
73	}
74
75	//________________________________________________________
76	Int_t AliStrLine::IsParallelTo(AliStrLine *line) const {
77	// returns 1 if lines are parallel, 0 if not paralel
78	Double_t cd2[3];
79	line->GetCd(cd2);
80	Double_t vecpx=fCd[1]cd2[2]-fCd[2]cd2[1];
81	if(vecpx!=0) return 0;
82	Double_t vecpy=-fCd[0]cd2[2]+fCd[2]cd2[0];
83	if(vecpy!=0) return 0;
84	Double_t vecpz=fCd[0]cd2[1]-fCd[1]cd2[0];
85	if(vecpz!=0) return 0;
86	return 1;
87	}
88	//________________________________________________________
89	Int_t AliStrLine::Crossrphi(AliStrLine *line){
90	// Cross 2 lines in the X-Y plane
91	Double_t p2[3];
92	Double_t cd2[3];
93	line->GetP0(p2);
94	line->GetCd(cd2);
95	Double_t a=fCd[0];
96	Double_t b=-cd2[0];
97	Double_t c=p2[0]-fP0[0];
98	Double_t d=fCd[1];
99	Double_t e=-cd2[1];
100	Double_t f=p2[1]-fP0[1];
101	Double_t deno = ae-bd;
102	Int_t retcode = 0;
103	if(deno != 0.) {
104	fTpar = (ce-bf)/deno;
105	}
106	else {
107	retcode = -1;
108	}
109	return retcode;
110	}
111
112	//________________________________________________________
113	Int_t AliStrLine::CrossPoints(AliStrLine line, Double_t point1, Double_t *point2){
114	// Looks for the crossing point estimated starting from the
115	// DCA segment
116	Double_t p2[3];
117	Double_t cd2[3];
118	line->GetP0(p2);
119	line->GetCd(cd2);
120	Int_t i;
121	Double_t k1 = 0;
122	for(i=0;i<3;i++)k1+=(fP0[i]-p2[i])*fCd[i];
123	Double_t k2 = 0;
124	for(i=0;i<3;i++)k2+=(fP0[i]-p2[i])*cd2[i];
125	Double_t a11 = 0;
126	for(i=0;i<3;i++)a11+=fCd[i]*cd2[i];
127	Double_t a22 = -a11;
128	Double_t a21 = 0;
129	for(i=0;i<3;i++)a21+=cd2[i]*cd2[i];
130	Double_t a12 = 0;
131	for(i=0;i<3;i++)a12-=fCd[i]*fCd[i];
132	Double_t deno = a11a22-a21a12;
133	if(deno == 0.) return -1;
134	fTpar = (a11k2-a21k1) / deno;
135	Double_t par2 = (k1a22-k2a12) / deno;
136	line->SetPar(par2);
137	GetCurrentPoint(point1);
138	line->GetCurrentPoint(point2);
139	return 0;
140	}
141	//________________________________________________________________
142	Int_t AliStrLine::Cross(AliStrLine line, Double_t point){
143
144	//Finds intersection between lines
145	Double_t point1[3];
146	Double_t point2[3];
147	Int_t retcod=CrossPoints(line,point1,point2);
148	if(retcod==0){
149	for(Int_t i=0;i<3;i++)point[i]=(point1[i]+point2[i])/2.;
150	return 0;
151	}else{
152	return -1;
153	}
154	}
155
156	//___________________________________________________________
157	Double_t AliStrLine::GetDCA(AliStrLine *line){
158	//Returns the distance of closest approach between two lines
159	Double_t p2[3];
160	Double_t cd2[3];
161	line->GetP0(p2);
162	line->GetCd(cd2);
163	Int_t i;
164	Int_t ispar=IsParallelTo(line);
165	if(ispar){
166	Double_t dist1q=0,dist2=0,mod=0;
167	for(i=0;i<3;i++){
168	dist1q+=(fP0[i]-p2[i])*(fP0[i]-p2[i]);
169	dist2+=(fP0[i]-p2[i])*fCd[i];
170	mod+=fCd[i]*fCd[i];
171	}
172	if(mod!=0){
173	dist2/=mod;
174	return TMath::Sqrt(dist1q-dist2*dist2);
175	}else{return -1;}
176	}else{
177	Double_t perp[3];
178	perp[0]=fCd[1]cd2[2]-fCd[2]cd2[1];
179	perp[1]=-fCd[0]cd2[2]+fCd[2]cd2[0];
180	perp[2]=fCd[0]cd2[1]-fCd[1]cd2[0];
181	Double_t mod=0,dist=0;
182	for(i=0;i<3;i++){
183	mod+=perp[i]*perp[i];
184	dist+=(fP0[i]-p2[i])*perp[i];
185	}
186	mod=sqrt(mod);
187	if(mod!=0){
188	dist/=mod;
189	return TMath::Abs(dist);
190	}else{return -1;}
191	}
192	}
193	//________________________________________________________
194	void AliStrLine::GetCurrentPoint(Double_t *point) const {
195	// Fills the array point with the current value on the line
196	for(Int_t i=0;i<3;i++)point[i]=fP0[i]+fCd[i]*fTpar;
197	}