[u/mrichter/AliRoot.git] / ITS / AliITSsegmentationSSD.cxx

/**************************************************************************
 * Copyright(c) 1998-1999, 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.                  *
 **************************************************************************/

/* $Id$ */

#include <TMath.h>
#include <TF1.h>
#include <Riostream.h>
#include "AliITSsegmentationSSD.h"
#include "AliITSgeom.h"
#include "AliRun.h"
#include "AliModule.h"

ClassImp(AliITSsegmentationSSD)
AliITSsegmentationSSD::AliITSsegmentationSSD(){
    // default constructor
    fGeom  = 0;
    fCorr  = 0;
    fLayer = 0;
}
//----------------------------------------------------------------------
AliITSsegmentationSSD::AliITSsegmentationSSD(AliITSgeom *geom){
    // constuctor
    fGeom = geom;
    fCorr = 0;
    SetDetSize();
    SetPadSize();
    SetNPads();
    SetAngles();
    fLayer = 0;
}
//______________________________________________________________________
AliITSsegmentationSSD& AliITSsegmentationSSD::operator=(
                                             AliITSsegmentationSSD &source){
// Operator =
    if(this==&source) return *this;
    this->fNstrips = source.fNstrips;
    this->fStereoP = source.fStereoP;
    this->fStereoN = source.fStereoN;
    this->fStereoPl5 = source.fStereoPl5;
    this->fStereoNl5 = source.fStereoNl5;
    this->fStereoPl6 = source.fStereoPl6;
    this->fStereoNl6 = source.fStereoNl6;
    this->fLayer   = source.fLayer;
    this->fPitch   = source.fPitch;
    this->fDz      = source.fDz;
    this->fDx      = source.fDx;
    this->fDy      = source.fDy;
    this->fLayer   = source.fLayer;
    this->fGeom    = source.fGeom; // copy only the pointer
    this->fCorr    = new TF1(*(source.fCorr)); // make a proper copy
    return *this;     
}
//______________________________________________________________________
AliITSsegmentationSSD::AliITSsegmentationSSD(AliITSsegmentationSSD &source):
    AliITSsegmentation(source){
    // copy constructor
    *this = source;
}
//----------------------------------------------------------------------
void AliITSsegmentationSSD::Init(){
    // standard initalizer

    SetPadSize();
    SetNPads();
    SetAngles();
}
//----------------------------------------------------------------------
void AliITSsegmentationSSD::Angles(Float_t &aP,Float_t &aN){

    if (fLayer == 5){
	aP = fStereoPl5;
	aN = fStereoNl5;
    } // end if
    if (fLayer == 6){
	aP = fStereoPl6;
	aN = fStereoNl6;
    } // end if
}
//----------------------------------------------------------------------
void AliITSsegmentationSSD::SetLayer(Int_t l){

    if (l==5) fLayer =5;
    if (l==6) fLayer =6;
}
//----------------------------------------------------------------------
void AliITSsegmentationSSD::GetPadTxz(Float_t &x,Float_t &z){
    // returns P and N sided strip numbers for a given location.
    // Transformation from microns detector center local coordinates
    // to detector P and N side strip numbers..
    /*                       _-  Z
                    + angle /    ^
        fNstrips           v     |   N-Side        ...0
            \-------/------------|-----------\--------\
            |\\\\\\/////////////.|\\\\\\\\\\\\\\\\\\\\|
            |0\\\\/////////////..|.\\\\\\\\\\\\\\\\\\\|
            |00\\/////////////...|..\\\\\\\\\\\\\\\\\\|
       X <--|000/////////////... |...\\\\\\\\\\\\\\\\\|
            |00/////////////...  | ...\\\\\\\\\\\\\\\\|
            |0/////////////...   |  ...\\\\\\\\\\\\\\\|
            |//////////////...   |  ...\\\\\\\\\\\\\\\|
            /-----\--------------|--------------------/
        fNstrips-1             P-Side              ...0
                     |0\
                     |00\
	Dead region: |000/
                     |00/
                     |0/
    // expects x, z in microns
    */
    Float_t StereoP, StereoN;
    Angles(StereoP,StereoN);
    Float_t tanP = TMath::Tan(StereoP);
    Float_t tanN = TMath::Tan(-StereoN);
    Float_t x1 = x;
    Float_t z1 = z;
    x1 += fDx/2;
    z1 += fDz/2;
    x   = (x1 - z1*tanP)/fPitch;
    z   = (x1 - tanN*(z1 - fDz))/fPitch;
}
//----------------------------------------------------------------------
void AliITSsegmentationSSD::GetPadIxz(Float_t x,Float_t z,Int_t &iP,Int_t &iN){
  // returns P and N sided strip numbers for a given location.
    /*                       _-  Z
                    + angle /    ^
        fNstrips           v     |   N-Side        ...0
            \-------/------------|-----------\--------\
            |\\\\\\/////////////.|\\\\\\\\\\\\\\\\\\\\|
            |0\\\\/////////////..|.\\\\\\\\\\\\\\\\\\\|
            |00\\/////////////...|..\\\\\\\\\\\\\\\\\\|
       X <--|000/////////////... |...\\\\\\\\\\\\\\\\\|
            |00/////////////...  | ...\\\\\\\\\\\\\\\\|
            |0/////////////...   |  ...\\\\\\\\\\\\\\\|
            |//////////////...   |  ...\\\\\\\\\\\\\\\|
            /-----\--------------|--------------------/
        fNstrips-1             P-Side              ...0
                     |0\
                     |00\
	Dead region: |000/
                     |00/
                     |0/

    // expects x, z in microns
  */ 

    Float_t StereoP, StereoN;
    Angles(StereoP,StereoN);
    Float_t tanP=TMath::Tan(StereoP);
    Float_t tanN=TMath::Tan(StereoN);
    Float_t x1=x,z1=z;
    x1 += fDx/2;
    z1 += fDz/2;
    Float_t  ldX = x1 - z1*tanP;          // distance from left-down edge 
    iP = (Int_t)(ldX/fPitch);
    iP = (iP<0)? -1: iP;      
    iP = (iP>fNstrips)? -1: iP;

    ldX = x1 - tanN*(fDz - z1);
    iN = (Int_t)(ldX/fPitch);
    iN = (iN<0)? -1: iN;
    iN = (iN>fNstrips)? -1: iN;

}
//-------------------------------------------------------
void AliITSsegmentationSSD::GetPadCxz(Int_t iP,Int_t iN,Float_t &x,Float_t &z){
    // actually this is the GetCrossing(Float_t &,Float_t &)
    // returns local x, z  in microns !

    Float_t Dx = fDx; // detector size in x direction, microns
    Float_t Dz = fDz; // detector size in z direction, microns
    Float_t xP; // x coordinate in the P side from the first P strip
    Float_t xN; // x coordinate in the N side from the first N strip
    Float_t StereoP, StereoN;
    Angles(StereoP,StereoN);
    Float_t kP=TMath::Tan(StereoP);
    Float_t kN=TMath::Tan(StereoN);

    xP=iP*fPitch;
    xN=iN*fPitch; 
    x = xP + kP*(Dz*kN-xP+xN)/(kP+kN);
    z = (Dz*kN-xP+xN)/(kP+kN); 
    x -= Dx/2;
    z -= Dz/2;
    //if(TMath::Abs(z) > Dz/2) cout<<"Warning, wrong z local ="<<z<<endl; 
    // Check that zL is inside the detector for the 
    // correspondent xP and xN coordinates

    return;   
}
//______________________________________________________________________
void AliITSsegmentationSSD::LocalToDet(Float_t x,Float_t z,
				       Int_t &iP,Int_t &iN){
    // Transformation from Geant cm detector center local coordinates
    // to detector P and N side strip numbers..
    /*                       _-  Z
                    + angle /    ^
        fNstrips           v     |   N-Side        ...0
            \-------/------------|-----------\--------\
            |\\\\\\/////////////.|\\\\\\\\\\\\\\\\\\\\|
            |0\\\\/////////////..|.\\\\\\\\\\\\\\\\\\\|
            |00\\/////////////...|..\\\\\\\\\\\\\\\\\\|
       X <--|000/////////////... |...\\\\\\\\\\\\\\\\\|
            |00/////////////...  | ...\\\\\\\\\\\\\\\\|
            |0/////////////...   |  ...\\\\\\\\\\\\\\\|
            |//////////////...   |  ...\\\\\\\\\\\\\\\|
            /-----\--------------|--------------------/
        fNstrips-1             P-Side              ...0
                     |0\
                     |00\
	Dead region: |000/
                     |00/
                     |0/
    */
    const Double_t kconst = 1.0E-04; // convert microns to cm.

    x /= kconst;  // convert to microns
    z /= kconst;  // convert to microns
    this->GetPadTxz(x,z);

    // first for P side
    iP = (Int_t) x;
    if(iP<0 || iP>=fNstrips) iP=-1; // strip number must be in range.
    // Now for N side)
    iN = (Int_t) z;
    if(iN<0 || iN>=fNstrips) iN=-1; // strip number must be in range.
    return;
}
//----------------------------------------------------------------------
void AliITSsegmentationSSD::DetToLocal(Int_t ix,Int_t iPN,
				       Float_t &x,Float_t &z){
    // Transformation from detector segmentation/cell coordiantes starting
    // from 0. iPN=0 for P side and 1 for N side strip. Returned is z=0.0
    // and the corresponding x value..
    /*                       _-  Z
                    + angle /    ^
        fNstrips           v     |   N-Side        ...0
            \-------/------------|-----------\--------\
            |\\\\\\/////////////.|\\\\\\\\\\\\\\\\\\\\|
            |0\\\\/////////////..|.\\\\\\\\\\\\\\\\\\\|
            |00\\/////////////...|..\\\\\\\\\\\\\\\\\\|
       X <--|000/////////////... |...\\\\\\\\\\\\\\\\\|
            |00/////////////...  | ...\\\\\\\\\\\\\\\\|
            |0/////////////...   |  ...\\\\\\\\\\\\\\\|
            |//////////////...   |  ...\\\\\\\\\\\\\\\|
            /-----\--------------|--------------------/
        fNstrips-1             P-Side              ...0
                     |0\
                     |00\
	Dead region: |000/
                     |00/
                     |0/
    */
    // for strips p-side
    // x = a + b + z*tan(fStereoP); a = Dpx(iP)*(iP+0.5)-dx; b = dz*th;
    // for strips n-side
    // x = a + b + z*tan(fStereoP); a = Dpx(iN)*(iN+0.5)-dx; b = -dz*th;
    const Double_t kconst = 1.0E-04; // convert microns to cm.
    Float_t flag=kconst*Dx(); // error value
    Double_t th=0.0,dx,dz,i,a,b=0.0,xb[4],zb[4];
    Float_t StereoP, StereoN;
    Angles(StereoP,StereoN);

    z = 0.0;  // Strip center in z.
    if(iPN<0 || iPN>1){// if error return full detector size in x.
	x = z = flag; 
	return;
    } // end if
    if(ix<0 || ix>=fNstrips) { // if error return full detector size in x.
	x = z = flag;
	return;
    } // end if
    i  = (Double_t) ix;      // convert to double
    dx = 0.5*kconst*Dx();    // half distance in x in cm
    dz = 0.5*kconst*Dz();    // half distance in z in cm
    a  = kconst*Dpx(ix)*(i+0.5)-dx; // Min x value.
    if(iPN==0){ //P-side angle defined backwards.
	th = TMath::Tan(StereoP); 
	b  = dz*th;
    }else if(iPN==1){ // N-side
	 th = TMath::Tan(-StereoN);
	 b  = -dz*th;
    } // end if
    // compute average/center position of the strip.
    xb[0] = +dx; if(th!=0.0) zb[0] = (+dx-a-b)/th; else zb[0] = 0.0;
    xb[1] = -dx; if(th!=0.0) zb[1] = (-dx-a-b)/th; else zb[1] = 0.0;
    xb[2] = a+b+dz*th; zb[2] = +dz;
    xb[3] = a+b-dz*th; zb[3] = -dz;
    x = 0.0; z = 0.0;
    for(Int_t j=0;j<4;j++){
	if(xb[j]>=-dx && xb[j]<=dx && zb[j]>=-dz && zb[j]<=dz){
	    x += xb[j];
	    z += zb[j];
	} // end if
    } // end for
    x *= 0.5;
    z *= 0.5;
    return;
}
//----------------------------------------------------------------------
Bool_t AliITSsegmentationSSD::GetCrossing(Int_t iP,Int_t iN,
					  Float_t &x,Float_t &z,
					  Float_t c[2][2]){
    // Given one P side strip and one N side strip, Returns kTRUE if they
    // cross each other and the location of the two crossing strips and
    // their correxlation matrix c[2][2].
    /*                       _-  Z
                    + angle /    ^
        fNstrips           v     |   N-Side        ...0
            \-------/------------|-----------\--------\
            |\\\\\\/////////////.|\\\\\\\\\\\\\\\\\\\\|
            |0\\\\/////////////..|.\\\\\\\\\\\\\\\\\\\|
            |00\\/////////////...|..\\\\\\\\\\\\\\\\\\|
       X <--|000/////////////... |...\\\\\\\\\\\\\\\\\|
            |00/////////////...  | ...\\\\\\\\\\\\\\\\|
            |0/////////////...   |  ...\\\\\\\\\\\\\\\|
            |//////////////...   |  ...\\\\\\\\\\\\\\\|
            /-----\--------------|--------------------/
        fNstrips-1             P-Side              ...0
                     |0\
                     |00\
	Dead region: |000/
                     |00/
                     |0/
       c[2][2] is defined as follows
       /c[0][0]  c[0][1]\ /delta iP\ = /delta x\
       \c[1][0]  c[1][1]/ \delta iN/ = \delta z/
    */
    const Double_t kconst = 1.0E-04; // convert microns to cm.
    Double_t thp,thn,th,dx,dz,p,ip,in;
    Float_t StereoP, StereoN;
    Angles(StereoP,StereoN);
    
    thp = TMath::Tan(StereoP);
    thn = TMath::Tan(-StereoN);
    th  = thp-thn;
    if(th==0.0) { // parall strips then never cross.
	x = 0.0;
	z = 0.0;
	c[0][0] = c[1][0] = c[0][1] = c[1][1] = 0.0;
	return kFALSE;
    } // end if
    // The strips must cross some place in space.
    ip = (Double_t) iP;       // convert to double now for speed
    in = (Double_t) iN;       // convert to double now for speed
    dx = 0.5*kconst*Dx();     // half distance in x in cm
    dz = 0.5*kconst*Dz();     // half distance in z in cm
    p  = kconst*Dpx(iP);      // Get strip spacing/pitch now
    x  = 0.5*p+dx + (p*(in*thp-ip*thn)-2.0*dz*thp*thn)/th;
    z  =(p*(in-ip)-dz*(thp+thn))/th;
    // compute correlations.
    c[0][0] = -thn*p/th; // dx/diP
    c[1][1] = p/th;      // dz/diN
    c[0][1] = p*thp/th;  // dx/diN
    c[1][0] = -p/th;     // dz/diP
    if(x<-dx || x>dx || z<-dz || z>dz) return kFALSE; // crossing is outside
                                                      // of the detector so
                                                      // these strips don't
                                                      // cross.
    return kTRUE;
}
Commit	Line	Data
b0f5e3fc	1	/**************************************************************************
	2	* Copyright(c) 1998-1999, 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	**************************************************************************/
4ae5bbc4	15
88cb7938	16	/* $Id$ */
b0f5e3fc	17
b0f5e3fc	18	#include <TMath.h>
1ca7869b	19	#include <TF1.h>
4ae5bbc4	20	#include <Riostream.h>
b0f5e3fc	21	#include "AliITSsegmentationSSD.h"
b0f5e3fc	22	#include "AliITSgeom.h"
9e1a0ddb	23	#include "AliRun.h"
9e1a0ddb	24	#include "AliModule.h"
fd61217e	25
b0f5e3fc	26	ClassImp(AliITSsegmentationSSD)
b0f5e3fc	27	AliITSsegmentationSSD::AliITSsegmentationSSD(){
179578b2	28	// default constructor
	29	fGeom = 0;
	30	fCorr = 0;
	31	fLayer = 0;
b0f5e3fc	32	}
179578b2	33	//----------------------------------------------------------------------
b0f5e3fc	34	AliITSsegmentationSSD::AliITSsegmentationSSD(AliITSgeom *geom){
179578b2	35	// constuctor
	36	fGeom = geom;
	37	fCorr = 0;
	38	SetDetSize();
	39	SetPadSize();
	40	SetNPads();
	41	SetAngles();
	42	fLayer = 0;
b0f5e3fc	43	}
179578b2	44	//______________________________________________________________________
	45	AliITSsegmentationSSD& AliITSsegmentationSSD::operator=(
	46	AliITSsegmentationSSD &source){
0315d466	47	// Operator =
179578b2	48	if(this==&source) return *this;
	49	this->fNstrips = source.fNstrips;
	50	this->fStereoP = source.fStereoP;
	51	this->fStereoN = source.fStereoN;
	52	this->fStereoPl5 = source.fStereoPl5;
	53	this->fStereoNl5 = source.fStereoNl5;
	54	this->fStereoPl6 = source.fStereoPl6;
	55	this->fStereoNl6 = source.fStereoNl6;
	56	this->fLayer = source.fLayer;
	57	this->fPitch = source.fPitch;
	58	this->fDz = source.fDz;
	59	this->fDx = source.fDx;
	60	this->fDy = source.fDy;
	61	this->fLayer = source.fLayer;
	62	this->fGeom = source.fGeom; // copy only the pointer
	63	this->fCorr = new TF1(*(source.fCorr)); // make a proper copy
	64	return *this;
b0f5e3fc	65	}
179578b2	66	//______________________________________________________________________
ac74f489	67	AliITSsegmentationSSD::AliITSsegmentationSSD(AliITSsegmentationSSD &source):
ac74f489	68	AliITSsegmentation(source){
179578b2	69	// copy constructor
179578b2	70	*this = source;
b0f5e3fc	71	}
179578b2	72	//----------------------------------------------------------------------
b0f5e3fc	73	void AliITSsegmentationSSD::Init(){
179578b2	74	// standard initalizer
b0f5e3fc	75
e8189707	76	SetPadSize();
e8189707	77	SetNPads();
b0f5e3fc	78	SetAngles();
179578b2	79	}
	80	//----------------------------------------------------------------------
	81	void AliITSsegmentationSSD::Angles(Float_t &aP,Float_t &aN){
0315d466	82
179578b2	83	if (fLayer == 5){
	84	aP = fStereoPl5;
	85	aN = fStereoNl5;
	86	} // end if
	87	if (fLayer == 6){
	88	aP = fStereoPl6;
	89	aN = fStereoNl6;
	90	} // end if
0315d466	91	}
179578b2	92	//----------------------------------------------------------------------
179578b2	93	void AliITSsegmentationSSD::SetLayer(Int_t l){
0315d466	94
179578b2	95	if (l==5) fLayer =5;
	96	if (l==6) fLayer =6;
	97	}
	98	//----------------------------------------------------------------------
	99	void AliITSsegmentationSSD::GetPadTxz(Float_t &x,Float_t &z){
	100	// returns P and N sided strip numbers for a given location.
	101	// Transformation from microns detector center local coordinates
	102	// to detector P and N side strip numbers..
	103	/* _- Z
	104	+ angle / ^
	105	fNstrips v \| N-Side ...0
	106	\-------/------------\|-----------\--------\
	107	\|\\\\\\/////////////.\|\\\\\\\\\\\\\\\\\\\\\|
	108	\|0\\\\/////////////..\|.\\\\\\\\\\\\\\\\\\\\|
	109	\|00\\/////////////...\|..\\\\\\\\\\\\\\\\\\\|
	110	X <--\|000/////////////... \|...\\\\\\\\\\\\\\\\\\|
	111	\|00/////////////... \| ...\\\\\\\\\\\\\\\\\|
	112	\|0/////////////... \| ...\\\\\\\\\\\\\\\\|
	113	\|//////////////... \| ...\\\\\\\\\\\\\\\\|
	114	/-----\--------------\|--------------------/
	115	fNstrips-1 P-Side ...0
	116	\|0\
	117	\|00\
	118	Dead region: \|000/
	119	\|00/
	120	\|0/
	121	// expects x, z in microns
	122	*/
	123	Float_t StereoP, StereoN;
	124	Angles(StereoP,StereoN);
	125	Float_t tanP = TMath::Tan(StereoP);
	126	Float_t tanN = TMath::Tan(-StereoN);
	127	Float_t x1 = x;
	128	Float_t z1 = z;
	129	x1 += fDx/2;
	130	z1 += fDz/2;
	131	x = (x1 - z1*tanP)/fPitch;
	132	z = (x1 - tanN*(z1 - fDz))/fPitch;
	133	}
	134	//----------------------------------------------------------------------
	135	void AliITSsegmentationSSD::GetPadIxz(Float_t x,Float_t z,Int_t &iP,Int_t &iN){
0315d466	136	// returns P and N sided strip numbers for a given location.
179578b2	137	/* _- Z
	138	+ angle / ^
	139	fNstrips v \| N-Side ...0
	140	\-------/------------\|-----------\--------\
	141	\|\\\\\\/////////////.\|\\\\\\\\\\\\\\\\\\\\\|
	142	\|0\\\\/////////////..\|.\\\\\\\\\\\\\\\\\\\\|
	143	\|00\\/////////////...\|..\\\\\\\\\\\\\\\\\\\|
	144	X <--\|000/////////////... \|...\\\\\\\\\\\\\\\\\\|
	145	\|00/////////////... \| ...\\\\\\\\\\\\\\\\\|
	146	\|0/////////////... \| ...\\\\\\\\\\\\\\\\|
	147	\|//////////////... \| ...\\\\\\\\\\\\\\\\|
	148	/-----\--------------\|--------------------/
	149	fNstrips-1 P-Side ...0
	150	\|0\
	151	\|00\
	152	Dead region: \|000/
	153	\|00/
	154	\|0/
b0f5e3fc	155
b0f5e3fc	156	// expects x, z in microns
179578b2	157	*/
c1c63494	158
0315d466	159	Float_t StereoP, StereoN;
	160	Angles(StereoP,StereoN);
	161	Float_t tanP=TMath::Tan(StereoP);
	162	Float_t tanN=TMath::Tan(StereoN);
	163	Float_t x1=x,z1=z;
	164	x1 += fDx/2;
	165	z1 += fDz/2;
	166	Float_t ldX = x1 - z1*tanP; // distance from left-down edge
	167	iP = (Int_t)(ldX/fPitch);
b0f5e3fc	168	iP = (iP<0)? -1: iP;
b0f5e3fc	169	iP = (iP>fNstrips)? -1: iP;
0315d466	170
	171	ldX = x1 - tanN*(fDz - z1);
	172	iN = (Int_t)(ldX/fPitch);
b0f5e3fc	173	iN = (iN<0)? -1: iN;
b0f5e3fc	174	iN = (iN>fNstrips)? -1: iN;
0315d466	175
b0f5e3fc	176	}
0315d466	177	//-------------------------------------------------------
179578b2	178	void AliITSsegmentationSSD::GetPadCxz(Int_t iP,Int_t iN,Float_t &x,Float_t &z){
179578b2	179	// actually this is the GetCrossing(Float_t &,Float_t &)
0315d466	180	// returns local x, z in microns !
b0f5e3fc	181
179578b2	182	Float_t Dx = fDx; // detector size in x direction, microns
	183	Float_t Dz = fDz; // detector size in z direction, microns
	184	Float_t xP; // x coordinate in the P side from the first P strip
	185	Float_t xN; // x coordinate in the N side from the first N strip
	186	Float_t StereoP, StereoN;
	187	Angles(StereoP,StereoN);
	188	Float_t kP=TMath::Tan(StereoP);
	189	Float_t kN=TMath::Tan(StereoN);
b0f5e3fc	190
0315d466	191	xP=iP*fPitch;
	192	xN=iN*fPitch;
	193	x = xP + kP(DzkN-xP+xN)/(kP+kN);
	194	z = (Dz*kN-xP+xN)/(kP+kN);
	195	x -= Dx/2;
	196	z -= Dz/2;
66da7685	197	//if(TMath::Abs(z) > Dz/2) cout<<"Warning, wrong z local ="<<z<<endl;
0315d466	198	// Check that zL is inside the detector for the
0315d466	199	// correspondent xP and xN coordinates
b0f5e3fc	200
	201	return;
	202	}
179578b2	203	//______________________________________________________________________
	204	void AliITSsegmentationSSD::LocalToDet(Float_t x,Float_t z,
	205	Int_t &iP,Int_t &iN){
	206	// Transformation from Geant cm detector center local coordinates
	207	// to detector P and N side strip numbers..
	208	/* _- Z
	209	+ angle / ^
	210	fNstrips v \| N-Side ...0
	211	\-------/------------\|-----------\--------\
	212	\|\\\\\\/////////////.\|\\\\\\\\\\\\\\\\\\\\\|
	213	\|0\\\\/////////////..\|.\\\\\\\\\\\\\\\\\\\\|
	214	\|00\\/////////////...\|..\\\\\\\\\\\\\\\\\\\|
	215	X <--\|000/////////////... \|...\\\\\\\\\\\\\\\\\\|
	216	\|00/////////////... \| ...\\\\\\\\\\\\\\\\\|
	217	\|0/////////////... \| ...\\\\\\\\\\\\\\\\|
	218	\|//////////////... \| ...\\\\\\\\\\\\\\\\|
	219	/-----\--------------\|--------------------/
	220	fNstrips-1 P-Side ...0
	221	\|0\
	222	\|00\
	223	Dead region: \|000/
	224	\|00/
	225	\|0/
	226	*/
	227	const Double_t kconst = 1.0E-04; // convert microns to cm.
	228
	229	x /= kconst; // convert to microns
	230	z /= kconst; // convert to microns
	231	this->GetPadTxz(x,z);
5752a110	232
179578b2	233	// first for P side
	234	iP = (Int_t) x;
	235	if(iP<0 \|\| iP>=fNstrips) iP=-1; // strip number must be in range.
	236	// Now for N side)
	237	iN = (Int_t) z;
	238	if(iN<0 \|\| iN>=fNstrips) iN=-1; // strip number must be in range.
	239	return;
	240	}
	241	//----------------------------------------------------------------------
	242	void AliITSsegmentationSSD::DetToLocal(Int_t ix,Int_t iPN,
	243	Float_t &x,Float_t &z){
	244	// Transformation from detector segmentation/cell coordiantes starting
	245	// from 0. iPN=0 for P side and 1 for N side strip. Returned is z=0.0
	246	// and the corresponding x value..
	247	/* _- Z
	248	+ angle / ^
	249	fNstrips v \| N-Side ...0
	250	\-------/------------\|-----------\--------\
	251	\|\\\\\\/////////////.\|\\\\\\\\\\\\\\\\\\\\\|
	252	\|0\\\\/////////////..\|.\\\\\\\\\\\\\\\\\\\\|
	253	\|00\\/////////////...\|..\\\\\\\\\\\\\\\\\\\|
	254	X <--\|000/////////////... \|...\\\\\\\\\\\\\\\\\\|
	255	\|00/////////////... \| ...\\\\\\\\\\\\\\\\\|
	256	\|0/////////////... \| ...\\\\\\\\\\\\\\\\|
	257	\|//////////////... \| ...\\\\\\\\\\\\\\\\|
	258	/-----\--------------\|--------------------/
	259	fNstrips-1 P-Side ...0
	260	\|0\
	261	\|00\
	262	Dead region: \|000/
	263	\|00/
	264	\|0/
	265	*/
	266	// for strips p-side
	267	// x = a + b + ztan(fStereoP); a = Dpx(iP)(iP+0.5)-dx; b = dz*th;
	268	// for strips n-side
	269	// x = a + b + ztan(fStereoP); a = Dpx(iN)(iN+0.5)-dx; b = -dz*th;
	270	const Double_t kconst = 1.0E-04; // convert microns to cm.
	271	Float_t flag=kconst*Dx(); // error value
	272	Double_t th=0.0,dx,dz,i,a,b=0.0,xb[4],zb[4];
	273	Float_t StereoP, StereoN;
	274	Angles(StereoP,StereoN);
5752a110	275
179578b2	276	z = 0.0; // Strip center in z.
	277	if(iPN<0 \|\| iPN>1){// if error return full detector size in x.
	278	x = z = flag;
	279	return;
	280	} // end if
	281	if(ix<0 \|\| ix>=fNstrips) { // if error return full detector size in x.
	282	x = z = flag;
	283	return;
	284	} // end if
	285	i = (Double_t) ix; // convert to double
	286	dx = 0.5kconstDx(); // half distance in x in cm
	287	dz = 0.5kconstDz(); // half distance in z in cm
	288	a = kconstDpx(ix)(i+0.5)-dx; // Min x value.
	289	if(iPN==0){ //P-side angle defined backwards.
	290	th = TMath::Tan(StereoP);
	291	b = dz*th;
	292	}else if(iPN==1){ // N-side
	293	th = TMath::Tan(-StereoN);
	294	b = -dz*th;
	295	} // end if
	296	// compute average/center position of the strip.
	297	xb[0] = +dx; if(th!=0.0) zb[0] = (+dx-a-b)/th; else zb[0] = 0.0;
	298	xb[1] = -dx; if(th!=0.0) zb[1] = (-dx-a-b)/th; else zb[1] = 0.0;
	299	xb[2] = a+b+dz*th; zb[2] = +dz;
	300	xb[3] = a+b-dz*th; zb[3] = -dz;
	301	x = 0.0; z = 0.0;
	302	for(Int_t j=0;j<4;j++){
	303	if(xb[j]>=-dx && xb[j]<=dx && zb[j]>=-dz && zb[j]<=dz){
	304	x += xb[j];
	305	z += zb[j];
	306	} // end if
	307	} // end for
	308	x *= 0.5;
	309	z *= 0.5;
	310	return;
	311	}
	312	//----------------------------------------------------------------------
	313	Bool_t AliITSsegmentationSSD::GetCrossing(Int_t iP,Int_t iN,
	314	Float_t &x,Float_t &z,
	315	Float_t c[2][2]){
	316	// Given one P side strip and one N side strip, Returns kTRUE if they
	317	// cross each other and the location of the two crossing strips and
	318	// their correxlation matrix c[2][2].
	319	/* _- Z
	320	+ angle / ^
	321	fNstrips v \| N-Side ...0
	322	\-------/------------\|-----------\--------\
	323	\|\\\\\\/////////////.\|\\\\\\\\\\\\\\\\\\\\\|
	324	\|0\\\\/////////////..\|.\\\\\\\\\\\\\\\\\\\\|
	325	\|00\\/////////////...\|..\\\\\\\\\\\\\\\\\\\|
	326	X <--\|000/////////////... \|...\\\\\\\\\\\\\\\\\\|
	327	\|00/////////////... \| ...\\\\\\\\\\\\\\\\\|
	328	\|0/////////////... \| ...\\\\\\\\\\\\\\\\|
	329	\|//////////////... \| ...\\\\\\\\\\\\\\\\|
	330	/-----\--------------\|--------------------/
	331	fNstrips-1 P-Side ...0
	332	\|0\
	333	\|00\
	334	Dead region: \|000/
	335	\|00/
	336	\|0/
	337	c[2][2] is defined as follows
	338	/c[0][0] c[0][1]\ /delta iP\ = /delta x\
	339	\c[1][0] c[1][1]/ \delta iN/ = \delta z/
340	*/
341	const Double_t kconst = 1.0E-04; // convert microns to cm.
342	Double_t thp,thn,th,dx,dz,p,ip,in;
343	Float_t StereoP, StereoN;
344	Angles(StereoP,StereoN);
345
346	thp = TMath::Tan(StereoP);
347	thn = TMath::Tan(-StereoN);
348	th = thp-thn;
349	if(th==0.0) { // parall strips then never cross.
350	x = 0.0;
351	z = 0.0;
352	c[0][0] = c[1][0] = c[0][1] = c[1][1] = 0.0;
353	return kFALSE;
354	} // end if
355	// The strips must cross some place in space.
356	ip = (Double_t) iP; // convert to double now for speed
357	in = (Double_t) iN; // convert to double now for speed
358	dx = 0.5kconstDx(); // half distance in x in cm
359	dz = 0.5kconstDz(); // half distance in z in cm
360	p = kconst*Dpx(iP); // Get strip spacing/pitch now
361	x = 0.5p+dx + (p(inthp-ipthn)-2.0dzthp*thn)/th;
362	z =(p(in-ip)-dz(thp+thn))/th;
363	// compute correlations.
364	c[0][0] = -thn*p/th; // dx/diP
365	c[1][1] = p/th; // dz/diN
366	c[0][1] = p*thp/th; // dx/diN
367	c[1][0] = -p/th; // dz/diP
368	if(x<-dx \|\| x>dx \|\| z<-dz \|\| z>dz) return kFALSE; // crossing is outside
369	// of the detector so
370	// these strips don't
371	// cross.
372	return kTRUE;
373	}