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[u/mrichter/AliRoot.git] / ITS / AliITSVertexer3DTapan.cxx
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eb35e591 1/**************************************************************************
2 * Copyright(c) 2006-2008, 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// AliITSVertexer3DTapan class
18// This is a class for the 3d vertex finding
19// Origin: Tapan Nayak, VECC-CERN, Tapan.Nayak@cern.ch
20//-----------------------------------------------------------------
21
22#include <TH1.h>
23#include <TTree.h>
24#include <TClonesArray.h>
25
26#include <AliITSVertexer3DTapan.h>
27#include <AliITSRecPoint.h>
28#include <AliITSgeom.h>
29#include <AliESDVertex.h>
30
31ClassImp(AliITSVertexer3DTapan)
32
33Int_t AliITSVertexer3DTapan::LoadClusters(TTree *cTree) {
34 //--------------------------------------------------------------------
35 //This function loads the SPD clusters
36 //--------------------------------------------------------------------
37 TClonesArray dummy("AliITSRecPoint",10000), *clusters=&dummy;
38 TBranch *branch=cTree->GetBranch("ITSRecPoints");
39 branch->SetAddress(&clusters);
40
41 Int_t nentr=cTree->GetEntries(),nc1=0,nc2=0;
42 for (Int_t i=0; i<nentr; i++) {
43 if (!cTree->GetEvent(i)) continue;
44 //
45 // Below:
46 // "alpha" is the angle from the global X-axis to the
47 // local GEANT X'-axis ( rot[0]=cos(alpha) and rot[1]=sin(alpha) )
48 // "phi" is the angle from the global X-axis to the
49 // local cluster X"-axis
50 //
51
52 // Double_t rot[9]; fITSgeom->GetRotMatrix(i,rot);
53 Int_t lay,lad,det; fITSgeom->GetModuleId(i,lay,lad,det);
54
55 if (lay>2) break; //load the SPD clusters only
56
57 /*
58 Float_t tx,ty,tz; fITSgeom->GetTrans(lay,lad,det,tx,ty,tz);
59
60 Double_t alpha=TMath::ATan2(rot[1],rot[0])+TMath::Pi();
61 Double_t phi=TMath::Pi()/2+alpha;
62
63 if (lay==1) phi+=TMath::Pi();
64 Double_t cp=TMath::Cos(phi), sp=TMath::Sin(phi);
65 Double_t r=tx*cp+ty*sp;
66 */
67
68 Int_t ncl=clusters->GetEntriesFast();
69 Float_t hPhi;
70 while (ncl--) {
71 AliITSRecPoint *c=(AliITSRecPoint*)clusters->UncheckedAt(ncl);
72 Float_t pos[3];
73 c->GetGlobalXYZ(pos);
74 if (lay==1) {
75 /* fX1[nc1]= r*cp - c->GetY()*sp;
76 fY1[nc1]= r*sp + c->GetY()*cp;
77 fZ1[nc1]= c->GetZ(); */
78 fX1[nc1] = pos[0]; fY1[nc1] = pos[1]; fZ1[nc1] = pos[2];
79 CalculatePhi(fX1[nc1], fY1[nc1], hPhi);
80 fPhi1[nc1]= hPhi;
81 nc1++;
82 } else {
83 /* fX2[nc2]= r*cp - c->GetY()*sp;
84 fY2[nc2]= r*sp + c->GetY()*cp;
85 fZ2[nc2]= c->GetZ(); */
86 fX2[nc2] = pos[0]; fY2[nc2] = pos[1]; fZ2[nc2] = pos[2];
87 CalculatePhi(fX2[nc2], fY2[nc2], hPhi);
88 fPhi2[nc2]= hPhi;
89 nc2++;
90 }
91 }
92 }
93 ficlu1 = nc1; ficlu2 = nc2;
94 AliInfo(Form("Number of clusters: %d (first layer) and %d (second layer)",ficlu1,ficlu2));
95 return 0;
96}
97
98void AliITSVertexer3DTapan::FindVertexForCurrentEvent(AliESDVertex *vtx) {
99 //
100 // This function reconstructs ....
101 //
102 //
103 if (vtx==0) return;
104
105 Double_t pos[3], postemp[3], sigpos[3];
106 Int_t ncontr, ncontrtemp;
107 Float_t cuts[3];
108 Int_t vtxstatus=0;
109
110 //....
111 pos[0] = 0.; pos[1] = 0.; pos[2] = 0.;
112 cuts[0]=1.; cuts[1]=1.; cuts[2]=20.;
113 CalculateVertex3d1(pos, cuts, ncontr);
114 if(ncontr==0) {
115 pos[0] = 9999.; pos[1] = 9999.; pos[2] = 9999.;
116 vtxstatus = -1;
117 }
118 AliInfo(Form("1st step: %d %f %f %f st=%d",ncontr,pos[0],pos[1],pos[2],vtxstatus));
119
120 if(vtxstatus == 0) {
121 ncontrtemp = ncontr; postemp[0] = pos[0]; postemp[1] = pos[1]; postemp[2] = pos[2];
122 cuts[0]=0.3; cuts[1]=0.3; cuts[2]=1.;
123 CalculateVertex3d1(pos, cuts, ncontr);
124 if(ncontr==0) {
125 ncontr = ncontrtemp; pos[0] = postemp[0]; pos[1] = postemp[1]; pos[2] = postemp[2];
126 vtxstatus = 2;
127 }
128 AliInfo(Form("2nd step: %d %f %f %f st=%d",ncontr,pos[0],pos[1],pos[2],vtxstatus));
129 }
130
131 if(vtxstatus == 0) {
132 ncontrtemp = ncontr; postemp[0] = pos[0]; postemp[1] = pos[1]; postemp[2] = pos[2];
133 cuts[0]=0.25; cuts[1]=0.25; cuts[2]=1.0;
134 CalculateVertex3d2(pos, cuts, ncontr, sigpos);
135 if(ncontr==0) {
136 ncontr = ncontrtemp; pos[0] = postemp[0]; pos[1] = postemp[1]; pos[2] = postemp[2];
137 vtxstatus = 3;
138 }
139 AliInfo(Form("3rd step: %d %f %f %f st=%d",ncontr,pos[0],pos[1],pos[2],vtxstatus));
140 }
141
142 if(vtxstatus == 0) {
143 ncontrtemp = ncontr; postemp[0] = pos[0]; postemp[1] = pos[1]; postemp[2] = pos[2];
144 cuts[0]=0.1; cuts[1]=0.1; cuts[2]=0.2;
145 CalculateVertex3d2(pos, cuts, ncontr, sigpos);
146 if(ncontr==0) {
147 ncontr = ncontrtemp; pos[0] = postemp[0]; pos[1] = postemp[1]; pos[2] = postemp[2];
148 vtxstatus = 4;
149 }
150 AliInfo(Form("4th step: %d %f %f %f st=%d",ncontr,pos[0],pos[1],pos[2],vtxstatus));
151 }
152 AliInfo(Form("Final step: %d %f %f %f st=%d",ncontr,pos[0],pos[1],pos[2],vtxstatus));
153
154 new(vtx) AliESDVertex(pos,sigpos,(Double_t)vtxstatus,ncontr,"AliITSVertexer3DTapan");
155 return;
156}
157
158
159void AliITSVertexer3DTapan::CalculateVertex3d1(Double_t pos[3], Float_t cuts[3], Int_t &ncontr) {
160 //
161 // This function reconstructs first two steps of vertex
162 //
163
164 Double_t p1[4], p2[4], p3[4], p4[4];
165 Double_t pa[3], pb[3];
166 Double_t hphi1, hphi2, hphi3, hphi4;
167
168 ncontr = 0;
169 Float_t phicut = 1.0;
170 Double_t distance; Float_t distancecut = 1.0;
171 Int_t ibin=20; Float_t ilow=-1.; Float_t ihigh=1.;
172 Int_t ibinz=400; Float_t ilowz=-20.; Float_t ihighz=20.;
173
174 TH1F *hx = new TH1F("hx","", ibin, ilow, ihigh);
175 TH1F *hy = new TH1F("hy","", ibin, ilow, ihigh);
176 TH1F *hz = new TH1F("hz","", ibinz,ilowz,ihighz);
177
178 for (Int_t ip1=0; ip1<ficlu1; ip1++) {
179 // Two points on layer1: p1 and p3
180 p1[0] = fX1[ip1]; p1[1] = fY1[ip1]; p1[2] = fZ1[ip1];
181 p3[0] = fX1[ip1+1]; p3[1] = fY1[ip1+1]; p3[2] = fZ1[ip1+1];
182 hphi1 = fPhi1[ip1]; hphi3 = fPhi1[ip1+1];
183
184 for (Int_t ip2=0; ip2<ficlu2; ip2++) {
185 // Two points on layer 2: p2 and p4
186 p2[0] = fX2[ip2]; p2[1] = fY2[ip2]; p2[2] = fZ2[ip2];
187 p4[0] = fX2[ip2+1]; p4[1] = fY2[ip2+1]; p4[2] = fZ2[ip2+1];
188 hphi2 = fPhi2[ip2]; hphi4 = fPhi2[ip2+1];
189
190 // First line is formed by p1-p2 and second line by p3-p4
191 // We find two points on each line which form the closest distance of the two lines
192 // pa[0],pa[1],pa[2]: points on line 1 and pb[0],pb[1],pb[2]: points on line 2
193 // Next: Consider x, y and z to be less than cuts[0], cuts[1] and cuts[2], respectively
194
195 if(TMath::Abs(hphi1-hphi2)<phicut && TMath::Abs(hphi3-hphi4)<phicut){
196 CalculateLine(p1, p2, p3, p4, pa, pb);
197
198 if (pa[0]>pos[0]-cuts[0] && pa[0]<pos[0]+cuts[0] && pa[1]>pos[1]-cuts[1] && pa[1]<pos[1]+cuts[1] && pa[2]>pos[2]-cuts[2] && pa[2]<pos[2]+cuts[2]){
199 distance = (TMath::Sqrt(pow((pa[0]-pb[0]),2) + pow((pa[1]-pb[1]),2) + pow((pa[2]-pb[2]),2)));
200 if(distance<distancecut){
201 hx->Fill(pa[0]); hy->Fill(pa[1]); hz->Fill(pa[2]);
202 hx->Fill(pb[0]); hy->Fill(pb[1]); hz->Fill(pb[2]);
203 ncontr++;
204 }
205 }
206 }
207
208 // Third line is formed by p1-p4 and fourth line by p3-p2
209 // We find two points on each line which form the closest distance of the two lines
210 // pa[0],pa[1],pa[2]: points on line 3 and pb[0],pb[1],pb[2]: points on line 4
211 // Next: Consider x, y and z to be less than cuts[0], cuts[1] and cuts[2], respectively
212 if(TMath::Abs(hphi1-hphi4)<phicut && TMath::Abs(hphi3-hphi2)<phicut) {
213 CalculateLine(p1, p4, p3, p2, pa, pb);
214 if (pa[0]>pos[0]-cuts[0] && pa[0]<pos[0]+cuts[0] && pa[1]>pos[1]-cuts[1] && pa[1]<pos[1]+cuts[1]){
215 distance = (TMath::Sqrt(pow((pa[0]-pb[0]),2) + pow((pa[1]-pb[1]),2) + pow((pa[2]-pb[2]),2)));
216 if(distance<distancecut){
217 hx->Fill(pa[0]); hy->Fill(pa[1]); hz->Fill(pa[2]);
218 hx->Fill(pb[0]); hy->Fill(pb[1]); hz->Fill(pb[2]);
219 ncontr++;
220 }
221 }
222 }
223 }
224 }
225
226 Int_t maxbinx = hx->GetMaximumBin();
227 Int_t maxbiny = hy->GetMaximumBin();
228 Int_t maxbinz = hz->GetMaximumBin();
229 pos[0] = ilow + ((ihigh-ilow)/ibin)*maxbinx;
230 pos[1] = ilow + ((ihigh-ilow)/ibin)*maxbiny;
231 pos[2] = ilowz + ((ihighz-ilowz)/ibinz)*maxbinz;
232 hx->Delete();
233 hy->Delete();
234 hz->Delete();
235}
236
237void AliITSVertexer3DTapan::CalculateVertex3d2(Double_t pos[3], Float_t cuts[3], Int_t &ncontr, Double_t sigpos[3]) {
238 //
239 // This function reconstructs second two steps of vertex
240 //
241
242 Double_t p1[4], p2[4], p3[4], p4[4];
243 Double_t pa[3], pb[3];
244 Double_t hphi1, hphi2, hphi3, hphi4;
245
246 ncontr = 0;
247 Float_t phicut = 0.3;
248 Double_t distance; Float_t distancecut = 1.0;
249
250 Double_t vertx =0.; Double_t verty =0.; Double_t vertz =0.;
251 Double_t vertx2 =0.; Double_t verty2 =0.; Double_t vertz2 =0.;
252
253 for (Int_t ip1=0; ip1<ficlu1; ip1++) {
254 // Two points on layer1: p1 and p3
255 p1[0] = fX1[ip1]; p1[1] = fY1[ip1]; p1[2] = fZ1[ip1];
256 p3[0] = fX1[ip1+1]; p3[1] = fY1[ip1+1]; p3[2] = fZ1[ip1+1];
257 hphi1 = fPhi1[ip1]; hphi3 = fPhi1[ip1+1];
258
259 for (Int_t ip2=0; ip2<ficlu2; ip2++) {
260 // Two points on layer 2: p2 and p4
261 p2[0] = fX2[ip2]; p2[1] = fY2[ip2]; p2[2] = fZ2[ip2];
262 p4[0] = fX2[ip2+1]; p4[1] = fY2[ip2+1]; p4[2] = fZ2[ip2+1];
263 hphi2 = fPhi2[ip2]; hphi4 = fPhi2[ip2+1];
264
265 // First line is formed by p1-p2 and second line by p3-p4
266 // We find two points on each line which form the closest distance of the two lines
267 // pa[0],pa[1],pa[2] are the points on line 1 and pb[0],pb[1],pb[2] are the points on line 2
268 // Next: Consider x, y and z to be less than cuts[0], cuts[1] and cuts[2], respectively
269
270 if(TMath::Abs(hphi1-hphi2)<phicut && TMath::Abs(hphi3-hphi4)<phicut){
271 CalculateLine(p1, p2, p3, p4, pa, pb);
272
273 // We consider the points where x, y and z points are less than xcut, ycut and zcut, respectively
274 if (pa[0]>pos[0]-cuts[0] && pa[0]<pos[0]+cuts[0] && pa[1]>pos[1]-cuts[1] && pa[1]<pos[1]+cuts[1] && pa[2]>pos[2]-cuts[2] && pa[2]<pos[2]+cuts[2]){
275 distance = (TMath::Sqrt(pow((pa[0]-pb[0]),2) + pow((pa[1]-pb[1]),2) + pow((pa[2]-pb[2]),2)));
276 if(distance<distancecut){
277 ncontr++;
278 vertx = vertx + pa[0]; verty = verty + pa[1]; vertz = vertz + pa[2];
279 vertx2 = vertx2 + pa[0]*pa[0]; verty2 = verty2 + pa[1]*pa[1]; vertz2 = vertz2 + pa[2]*pa[2];
280 ncontr++;
281 vertx = vertx + pb[0]; verty = verty + pb[1]; vertz = vertz + pb[2];
282 vertx2 = vertx2 + pb[0]*pb[0]; verty2 = verty2 + pb[1]*pb[1]; vertz2 = vertz2 + pb[2]*pb[2];
283 }
284 }
285 }
286
287 // Third line is formed by p1-p4 and fourth line by p3-p2
288 // We find two points on each line which form the closest distance of the two lines
289 // pa[0],pa[1],pa[2] are the points on line 3 and pb[0],pb[1],pb[2] are the points on line 4
290 // Next: Consider x, y and z to be less than cuts[0], cuts[1] and cuts[2], respectively
291 if(TMath::Abs(hphi1-hphi4)<phicut && TMath::Abs(hphi3-hphi2)<phicut) {
292
293 CalculateLine(p1, p4, p3, p2, pa, pb);
294 if (pa[0]>pos[0]-cuts[0] && pa[0]<pos[0]+cuts[0] && pa[1]>pos[1]-cuts[1] && pa[1]<pos[1]+cuts[1] && pa[2]>pos[2]-cuts[2] && pa[2]<pos[2]+cuts[2]){
295 distance = (TMath::Sqrt(pow((pa[0]-pb[0]),2) + pow((pa[1]-pb[1]),2) + pow((pa[2]-pb[2]),2)));
296 if(distance<distancecut){
297 ncontr++;
298 vertx = vertx + pa[0]; verty = verty + pa[1]; vertz = vertz + pa[2];
299 vertx2 = vertx2 + pa[0]*pa[0]; verty2 = verty2 + pa[1]*pa[1]; vertz2 = vertz2 + pa[2]*pa[2];
300 ncontr++;
301 vertx = vertx + pb[0]; verty = verty + pb[1]; vertz = vertz + pb[2];
302 vertx2 = vertx2 + pb[0]*pb[0]; verty2 = verty2 + pb[1]*pb[1]; vertz2 = vertz2 + pb[2]*pb[2];
303 }
304 }
305 }
306 }
307 }
308
309 if(ncontr>0){
310 pos[0] = vertx/ncontr; pos[1] = verty/ncontr; pos[2] = vertz/ncontr;
311 vertx2 = vertx2/ncontr; verty2 = verty2/ncontr; vertz2 = vertz2/ncontr;
312 sigpos[0] = TMath::Sqrt(vertx2 - pos[0]*pos[0]);
313 sigpos[1] = TMath::Sqrt(verty2 - pos[1]*pos[1]);
314 sigpos[2] = TMath::Sqrt(vertz2 - pos[2]*pos[2]);
315 }
316 ncontr = ncontr/2;
317}
318
319void AliITSVertexer3DTapan::CalculatePhi(Float_t fx, Float_t fy, Float_t & phi)
320{
321 //calculates phi
322 Float_t ybyx, phi1;
323 const Float_t kradian = 180./3.141592654;
324
325 if(fx==0.)
326 {
327 if(fy>0.) phi = 90.;
328 if(fy<0.) phi = 270.;
329 }
330 if(fx != 0.)
331 {
332 ybyx = fy/fx;
333 if(ybyx < 0) ybyx = - ybyx;
334 phi1 = TMath::ATan(ybyx)*kradian;
335 if(fx > 0 && fy > 0) phi = phi1; // 1st Quadrant
336 if(fx < 0 && fy > 0) phi = 180 - phi1; // 2nd Quadrant
337 if(fx < 0 && fy < 0) phi = 180 + phi1; // 3rd Quadrant
338 if(fx > 0 && fy < 0) phi = 360 - phi1; // 4th Quadrant
339
340 }
341 phi = phi/kradian;
342}
343
344void AliITSVertexer3DTapan::CalculateLine(Double_t p1[4], Double_t p2[4], Double_t p3[4], Double_t p4[4], Double_t pa[3], Double_t pb[3]) const{
345 //calculates line
346 Double_t p13x, p13y, p13z;
347 Double_t p21x, p21y, p21z;
348 Double_t p43x, p43y, p43z;
349 Double_t d1343, d4321, d1321, d4343, d2121;
350 Double_t numer, denom;
351 Double_t mua, mub;
352 mua = 0.; mub = 0.;
353
354 p13x = p1[0] - p3[0];
355 p13y = p1[1] - p3[1];
356 p13z = p1[2] - p3[2];
357
358 p21x = p2[0] - p1[0];
359 p21y = p2[1] - p1[1];
360 p21z = p2[2] - p1[2];
361
362 p43x = p4[0] - p3[0];
363 p43y = p4[1] - p3[1];
364 p43z = p4[2] - p3[2];
365
366 d1343 = p13x * p43x + p13y * p43y + p13z * p43z;
367 d4321 = p43x * p21x + p43y * p21y + p43z * p21z;
368 d1321 = p13x * p21x + p13y * p21y + p13z * p21z;
369 d4343 = p43x * p43x + p43y * p43y + p43z * p43z;
370 d2121 = p21x * p21x + p21y * p21y + p21z * p21z;
371
372 denom = d2121 * d4343 - d4321 * d4321;
373 numer = d1343 * d4321 - d1321 * d4343;
374
375 if(denom>0) mua = numer / denom;
376 if(d4343>0) mub = (d1343 + d4321 * (mua)) / d4343;
377
378 pa[0] = p1[0] + mua * p21x;
379 pa[1] = p1[1] + mua * p21y;
380 pa[2] = p1[2] + mua * p21z;
381
382 pb[0] = p3[0] + mub * p43x;
383 pb[1] = p3[1] + mub * p43y;
384 pb[2] = p3[2] + mub * p43z;
385}
386