[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.                  *
 **************************************************************************/

/* $Id$ */

///////////////////////////////////////////////////////////////////
//                                                               //
// A straight line is coded as a point (3 Double_t) and           //
// 3 direction cosines                                           //
//                                                               //
///////////////////////////////////////////////////////////////////

#include <Riostream.h>
#include <TTree.h>
#include <TMath.h>

#include "AliStrLine.h"

ClassImp(AliStrLine)

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

//________________________________________________________
AliStrLine::AliStrLine(Double_t *point, Double_t *cd,Bool_t twopoints) :
  TObject(),
  fTpar(0),
  fDebug(0)
{
  // Standard constructor
  // if twopoints is true:  point and cd are the 3D coordinates of
  //                        two points defininig the straight line
  // if twopoint is false: point represents the 3D coordinates of a point
  //                       belonging to the straight line and cd is the
  //                       direction in space
  if(twopoints){
    InitTwoPoints(point,cd);
  }
  else {
    InitDirection(point,cd);
  }
}

//________________________________________________________
AliStrLine::AliStrLine(Float_t *pointf, Float_t *cdf,Bool_t twopoints) :
  TObject(),
  fTpar(0),
  fDebug(0)
{
  // Standard constructor - with float arguments
  // if twopoints is true:  point and cd are the 3D coordinates of
  //                        two points defininig the straight line
  // if twopoint is false: point represents the 3D coordinates of a point
  //                       belonging to the straight line and cd is the
  //                       direction in space
  Double_t point[3];
  Double_t cd[3];
  for(Int_t i=0;i<3;i++){
    point[i] = pointf[i];
    cd[i] = cdf[i];
  }
  if(twopoints){
    InitTwoPoints(point,cd);
  }
  else {
    InitDirection(point,cd);
  }
}

//________________________________________________________
void AliStrLine::InitDirection(Double_t *point, Double_t *cd){
  // Initialization from a point and a direction
  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();
}

//________________________________________________________
void AliStrLine::InitTwoPoints(Double_t *pA, Double_t *pB){
  // Initialization from the coordinates of two
  // points in the space
  Double_t cd[3];
  for(Int_t i=0;i<3;i++)cd[i] = pB[i]-pA[i];
  InitDirection(pA,cd);
}

//________________________________________________________
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) const{
  //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;
}

//________________________________________________________
Double_t AliStrLine::GetDistFromPoint(Double_t *point) const {
  // computes distance from point 
  AliStrLine tmp(point,(Double_t *)fCd,kFALSE);
  return this->GetDCA(&tmp);
}
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	**************************************************************************/
090026bf	15
	16	/* $Id$ */
	17
edc97986	18	///////////////////////////////////////////////////////////////////
	19	// //
	20	// A straight line is coded as a point (3 Double_t) and //
	21	// 3 direction cosines //
	22	// //
	23	///////////////////////////////////////////////////////////////////
090026bf	24
edc97986	25	#include <Riostream.h>
edc97986	26	#include <TTree.h>
090026bf	27	#include <TMath.h>
090026bf	28
edc97986	29	#include "AliStrLine.h"
	30
	31	ClassImp(AliStrLine)
	32
	33	//________________________________________________________
fe12e09c	34	AliStrLine::AliStrLine() :
	35	TObject(),
	36	fTpar(0),
	37	fDebug(0)
	38	{
edc97986	39	// Default constructor
	40	for(Int_t i=0;i<3;i++) {
	41	fP0[i] = 0.;
	42	fCd[i] = 0.;
	43	}
edc97986	44	}
	45
	46	//________________________________________________________
fe12e09c	47	AliStrLine::AliStrLine(Double_t point, Double_t cd,Bool_t twopoints) :
	48	TObject(),
	49	fTpar(0),
	50	fDebug(0)
	51	{
edc97986	52	// Standard constructor
24a0c65f	53	// if twopoints is true: point and cd are the 3D coordinates of
	54	// two points defininig the straight line
	55	// if twopoint is false: point represents the 3D coordinates of a point
	56	// belonging to the straight line and cd is the
	57	// direction in space
	58	if(twopoints){
	59	InitTwoPoints(point,cd);
	60	}
	61	else {
	62	InitDirection(point,cd);
	63	}
	64	}
	65
2c9641ee	66	//________________________________________________________
	67	AliStrLine::AliStrLine(Float_t pointf, Float_t cdf,Bool_t twopoints) :
	68	TObject(),
	69	fTpar(0),
	70	fDebug(0)
	71	{
	72	// Standard constructor - with float arguments
	73	// if twopoints is true: point and cd are the 3D coordinates of
	74	// two points defininig the straight line
	75	// if twopoint is false: point represents the 3D coordinates of a point
	76	// belonging to the straight line and cd is the
	77	// direction in space
	78	Double_t point[3];
	79	Double_t cd[3];
	80	for(Int_t i=0;i<3;i++){
	81	point[i] = pointf[i];
	82	cd[i] = cdf[i];
	83	}
	84	if(twopoints){
	85	InitTwoPoints(point,cd);
	86	}
	87	else {
	88	InitDirection(point,cd);
	89	}
	90	}
24a0c65f	91
	92	//________________________________________________________
	93	void AliStrLine::InitDirection(Double_t point, Double_t cd){
	94	// Initialization from a point and a direction
edc97986	95	Double_t norm = 0.;
	96	for(Int_t i=0;i<3;i++)norm+=cd[i]*cd[i];
	97	if(norm) {
	98	norm = TMath::Sqrt(norm);
	99	for(Int_t i=0;i<3;i++) cd[i]/=norm;
	100	}
	101	else {
	102	Error("AliStrLine","Null direction cosines!!!");
	103	}
	104	SetP0(point);
	105	SetCd(cd);
	106	fTpar = 0.;
	107	SetDebug();
	108	}
	109
24a0c65f	110	//________________________________________________________
	111	void AliStrLine::InitTwoPoints(Double_t pA, Double_t pB){
	112	// Initialization from the coordinates of two
	113	// points in the space
	114	Double_t cd[3];
	115	for(Int_t i=0;i<3;i++)cd[i] = pB[i]-pA[i];
	116	InitDirection(pA,cd);
	117	}
	118
edc97986	119	//________________________________________________________
	120	AliStrLine::~AliStrLine() {
	121	// destructor
	122	}
	123
	124	//________________________________________________________
	125	void AliStrLine::PrintStatus() const {
	126	// Print current status
	127	cout <<"=======================================================\n";
	128	cout <<"Direction cosines: ";
	129	for(Int_t i=0;i<3;i++)cout <<fCd[i]<<"; ";
	130	cout <<endl;
	131	cout <<"Known point: ";
	132	for(Int_t i=0;i<3;i++)cout <<fP0[i]<<"; ";
	133	cout <<endl;
	134	cout <<"Current value for the parameter: "<<fTpar<<endl;
	135	cout <<" Debug flag: "<<fDebug<<endl;
	136	}
	137
	138	//________________________________________________________
	139	Int_t AliStrLine::IsParallelTo(AliStrLine *line) const {
	140	// returns 1 if lines are parallel, 0 if not paralel
	141	Double_t cd2[3];
	142	line->GetCd(cd2);
	143	Double_t vecpx=fCd[1]cd2[2]-fCd[2]cd2[1];
	144	if(vecpx!=0) return 0;
	145	Double_t vecpy=-fCd[0]cd2[2]+fCd[2]cd2[0];
	146	if(vecpy!=0) return 0;
	147	Double_t vecpz=fCd[0]cd2[1]-fCd[1]cd2[0];
	148	if(vecpz!=0) return 0;
	149	return 1;
	150	}
	151	//________________________________________________________
	152	Int_t AliStrLine::Crossrphi(AliStrLine *line){
	153	// Cross 2 lines in the X-Y plane
	154	Double_t p2[3];
	155	Double_t cd2[3];
	156	line->GetP0(p2);
	157	line->GetCd(cd2);
	158	Double_t a=fCd[0];
	159	Double_t b=-cd2[0];
	160	Double_t c=p2[0]-fP0[0];
	161	Double_t d=fCd[1];
	162	Double_t e=-cd2[1];
	163	Double_t f=p2[1]-fP0[1];
	164	Double_t deno = ae-bd;
	165	Int_t retcode = 0;
	166	if(deno != 0.) {
	167	fTpar = (ce-bf)/deno;
	168	}
	169	else {
	170	retcode = -1;
	171	}
	172	return retcode;
	173	}
	174
	175	//________________________________________________________
	176	Int_t AliStrLine::CrossPoints(AliStrLine line, Double_t point1, Double_t *point2){
	177	// Looks for the crossing point estimated starting from the
	178	// DCA segment
	179	Double_t p2[3];
	180	Double_t cd2[3];
	181	line->GetP0(p2);
	182	line->GetCd(cd2);
183	Int_t i;
184	Double_t k1 = 0;
185	for(i=0;i<3;i++)k1+=(fP0[i]-p2[i])*fCd[i];
186	Double_t k2 = 0;
187	for(i=0;i<3;i++)k2+=(fP0[i]-p2[i])*cd2[i];
188	Double_t a11 = 0;
189	for(i=0;i<3;i++)a11+=fCd[i]*cd2[i];
190	Double_t a22 = -a11;
191	Double_t a21 = 0;
192	for(i=0;i<3;i++)a21+=cd2[i]*cd2[i];
193	Double_t a12 = 0;
194	for(i=0;i<3;i++)a12-=fCd[i]*fCd[i];
195	Double_t deno = a11a22-a21a12;
196	if(deno == 0.) return -1;
197	fTpar = (a11k2-a21k1) / deno;
198	Double_t par2 = (k1a22-k2a12) / deno;
199	line->SetPar(par2);
200	GetCurrentPoint(point1);
201	line->GetCurrentPoint(point2);
202	return 0;
203	}
204	//________________________________________________________________
205	Int_t AliStrLine::Cross(AliStrLine line, Double_t point){
206
207	//Finds intersection between lines
208	Double_t point1[3];
209	Double_t point2[3];
210	Int_t retcod=CrossPoints(line,point1,point2);
211	if(retcod==0){
212	for(Int_t i=0;i<3;i++)point[i]=(point1[i]+point2[i])/2.;
213	return 0;
214	}else{
215	return -1;
216	}
217	}
218
219	//___________________________________________________________
2c9641ee	220	Double_t AliStrLine::GetDCA(AliStrLine *line) const{
edc97986	221	//Returns the distance of closest approach between two lines
	222	Double_t p2[3];
	223	Double_t cd2[3];
	224	line->GetP0(p2);
	225	line->GetCd(cd2);
	226	Int_t i;
	227	Int_t ispar=IsParallelTo(line);
	228	if(ispar){
	229	Double_t dist1q=0,dist2=0,mod=0;
	230	for(i=0;i<3;i++){
	231	dist1q+=(fP0[i]-p2[i])*(fP0[i]-p2[i]);
	232	dist2+=(fP0[i]-p2[i])*fCd[i];
	233	mod+=fCd[i]*fCd[i];
	234	}
	235	if(mod!=0){
	236	dist2/=mod;
	237	return TMath::Sqrt(dist1q-dist2*dist2);
	238	}else{return -1;}
	239	}else{
	240	Double_t perp[3];
	241	perp[0]=fCd[1]cd2[2]-fCd[2]cd2[1];
	242	perp[1]=-fCd[0]cd2[2]+fCd[2]cd2[0];
	243	perp[2]=fCd[0]cd2[1]-fCd[1]cd2[0];
	244	Double_t mod=0,dist=0;
	245	for(i=0;i<3;i++){
	246	mod+=perp[i]*perp[i];
	247	dist+=(fP0[i]-p2[i])*perp[i];
	248	}
	249	mod=sqrt(mod);
	250	if(mod!=0){
	251	dist/=mod;
	252	return TMath::Abs(dist);
	253	}else{return -1;}
	254	}
	255	}
	256	//________________________________________________________
	257	void AliStrLine::GetCurrentPoint(Double_t *point) const {
	258	// Fills the array point with the current value on the line
	259	for(Int_t i=0;i<3;i++)point[i]=fP0[i]+fCd[i]*fTpar;
	260	}
2c9641ee	261
	262	//________________________________________________________
	263	Double_t AliStrLine::GetDistFromPoint(Double_t *point) const {
	264	// computes distance from point
	265	AliStrLine tmp(point,(Double_t *)fCd,kFALSE);
	266	return this->GetDCA(&tmp);
	267	}