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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>
37add1d1 28#include <AliITSgeomTGeo.h>
eb35e591 29#include <AliESDVertex.h>
30
31ClassImp(AliITSVertexer3DTapan)
32
308c2f7c 33void AliITSVertexer3DTapan::LoadClusters(TTree *cTree) {
eb35e591 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
37add1d1 52 Int_t lay,lad,det; AliITSgeomTGeo::GetModuleId(i,lay,lad,det);
eb35e591 53
54 if (lay>2) break; //load the SPD clusters only
55
eb35e591 56 Int_t ncl=clusters->GetEntriesFast();
225cff59 57 Float_t hPhi=0.;
eb35e591 58 while (ncl--) {
59 AliITSRecPoint *c=(AliITSRecPoint*)clusters->UncheckedAt(ncl);
60 Float_t pos[3];
61 c->GetGlobalXYZ(pos);
62 if (lay==1) {
63 /* fX1[nc1]= r*cp - c->GetY()*sp;
64 fY1[nc1]= r*sp + c->GetY()*cp;
65 fZ1[nc1]= c->GetZ(); */
66 fX1[nc1] = pos[0]; fY1[nc1] = pos[1]; fZ1[nc1] = pos[2];
67 CalculatePhi(fX1[nc1], fY1[nc1], hPhi);
68 fPhi1[nc1]= hPhi;
69 nc1++;
70 } else {
71 /* fX2[nc2]= r*cp - c->GetY()*sp;
72 fY2[nc2]= r*sp + c->GetY()*cp;
73 fZ2[nc2]= c->GetZ(); */
74 fX2[nc2] = pos[0]; fY2[nc2] = pos[1]; fZ2[nc2] = pos[2];
75 CalculatePhi(fX2[nc2], fY2[nc2], hPhi);
76 fPhi2[nc2]= hPhi;
77 nc2++;
78 }
79 }
80 }
81 ficlu1 = nc1; ficlu2 = nc2;
82 AliInfo(Form("Number of clusters: %d (first layer) and %d (second layer)",ficlu1,ficlu2));
eb35e591 83}
84
308c2f7c 85AliESDVertex *AliITSVertexer3DTapan::FindVertexForCurrentEvent(TTree *cTree) {
eb35e591 86 //
87 // This function reconstructs ....
88 //
89 //
308c2f7c 90 LoadClusters(cTree);
eb35e591 91
225cff59 92 Double_t pos[3], postemp[3];
93 Double_t sigpos[3]={0.,0.,0.};
eb35e591 94 Int_t ncontr, ncontrtemp;
95 Float_t cuts[3];
96 Int_t vtxstatus=0;
97
98 //....
99 pos[0] = 0.; pos[1] = 0.; pos[2] = 0.;
100 cuts[0]=1.; cuts[1]=1.; cuts[2]=20.;
101 CalculateVertex3d1(pos, cuts, ncontr);
102 if(ncontr==0) {
103 pos[0] = 9999.; pos[1] = 9999.; pos[2] = 9999.;
104 vtxstatus = -1;
105 }
106 AliInfo(Form("1st step: %d %f %f %f st=%d",ncontr,pos[0],pos[1],pos[2],vtxstatus));
107
108 if(vtxstatus == 0) {
109 ncontrtemp = ncontr; postemp[0] = pos[0]; postemp[1] = pos[1]; postemp[2] = pos[2];
110 cuts[0]=0.3; cuts[1]=0.3; cuts[2]=1.;
111 CalculateVertex3d1(pos, cuts, ncontr);
112 if(ncontr==0) {
113 ncontr = ncontrtemp; pos[0] = postemp[0]; pos[1] = postemp[1]; pos[2] = postemp[2];
114 vtxstatus = 2;
115 }
116 AliInfo(Form("2nd step: %d %f %f %f st=%d",ncontr,pos[0],pos[1],pos[2],vtxstatus));
117 }
118
119 if(vtxstatus == 0) {
120 ncontrtemp = ncontr; postemp[0] = pos[0]; postemp[1] = pos[1]; postemp[2] = pos[2];
121 cuts[0]=0.25; cuts[1]=0.25; cuts[2]=1.0;
122 CalculateVertex3d2(pos, cuts, ncontr, sigpos);
123 if(ncontr==0) {
124 ncontr = ncontrtemp; pos[0] = postemp[0]; pos[1] = postemp[1]; pos[2] = postemp[2];
125 vtxstatus = 3;
126 }
127 AliInfo(Form("3rd step: %d %f %f %f st=%d",ncontr,pos[0],pos[1],pos[2],vtxstatus));
128 }
129
130 if(vtxstatus == 0) {
131 ncontrtemp = ncontr; postemp[0] = pos[0]; postemp[1] = pos[1]; postemp[2] = pos[2];
132 cuts[0]=0.1; cuts[1]=0.1; cuts[2]=0.2;
133 CalculateVertex3d2(pos, cuts, ncontr, sigpos);
134 if(ncontr==0) {
135 ncontr = ncontrtemp; pos[0] = postemp[0]; pos[1] = postemp[1]; pos[2] = postemp[2];
136 vtxstatus = 4;
137 }
138 AliInfo(Form("4th step: %d %f %f %f st=%d",ncontr,pos[0],pos[1],pos[2],vtxstatus));
139 }
140 AliInfo(Form("Final step: %d %f %f %f st=%d",ncontr,pos[0],pos[1],pos[2],vtxstatus));
141
225cff59 142 Double_t covma[6]={0.,0.,0.,0.,0.,0.};
143 covma[0]=sigpos[0];
144 covma[2]=sigpos[1];
145 covma[5]=sigpos[2];
146 return new AliESDVertex(pos,covma,(Double_t)vtxstatus,ncontr,"AliITSVertexer3DTapan");
308c2f7c 147
eb35e591 148}
149
150
151void AliITSVertexer3DTapan::CalculateVertex3d1(Double_t pos[3], Float_t cuts[3], Int_t &ncontr) {
152 //
153 // This function reconstructs first two steps of vertex
154 //
155
156 Double_t p1[4], p2[4], p3[4], p4[4];
157 Double_t pa[3], pb[3];
158 Double_t hphi1, hphi2, hphi3, hphi4;
159
160 ncontr = 0;
161 Float_t phicut = 1.0;
162 Double_t distance; Float_t distancecut = 1.0;
163 Int_t ibin=20; Float_t ilow=-1.; Float_t ihigh=1.;
164 Int_t ibinz=400; Float_t ilowz=-20.; Float_t ihighz=20.;
165
166 TH1F *hx = new TH1F("hx","", ibin, ilow, ihigh);
167 TH1F *hy = new TH1F("hy","", ibin, ilow, ihigh);
168 TH1F *hz = new TH1F("hz","", ibinz,ilowz,ihighz);
169
170 for (Int_t ip1=0; ip1<ficlu1; ip1++) {
171 // Two points on layer1: p1 and p3
172 p1[0] = fX1[ip1]; p1[1] = fY1[ip1]; p1[2] = fZ1[ip1];
173 p3[0] = fX1[ip1+1]; p3[1] = fY1[ip1+1]; p3[2] = fZ1[ip1+1];
174 hphi1 = fPhi1[ip1]; hphi3 = fPhi1[ip1+1];
175
176 for (Int_t ip2=0; ip2<ficlu2; ip2++) {
177 // Two points on layer 2: p2 and p4
178 p2[0] = fX2[ip2]; p2[1] = fY2[ip2]; p2[2] = fZ2[ip2];
179 p4[0] = fX2[ip2+1]; p4[1] = fY2[ip2+1]; p4[2] = fZ2[ip2+1];
180 hphi2 = fPhi2[ip2]; hphi4 = fPhi2[ip2+1];
181
182 // First line is formed by p1-p2 and second line by p3-p4
183 // We find two points on each line which form the closest distance of the two lines
184 // pa[0],pa[1],pa[2]: points on line 1 and pb[0],pb[1],pb[2]: points on line 2
185 // Next: Consider x, y and z to be less than cuts[0], cuts[1] and cuts[2], respectively
186
187 if(TMath::Abs(hphi1-hphi2)<phicut && TMath::Abs(hphi3-hphi4)<phicut){
188 CalculateLine(p1, p2, p3, p4, pa, pb);
189
190 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]){
191 distance = (TMath::Sqrt(pow((pa[0]-pb[0]),2) + pow((pa[1]-pb[1]),2) + pow((pa[2]-pb[2]),2)));
192 if(distance<distancecut){
193 hx->Fill(pa[0]); hy->Fill(pa[1]); hz->Fill(pa[2]);
194 hx->Fill(pb[0]); hy->Fill(pb[1]); hz->Fill(pb[2]);
195 ncontr++;
196 }
197 }
198 }
199
200 // Third line is formed by p1-p4 and fourth line by p3-p2
201 // We find two points on each line which form the closest distance of the two lines
202 // pa[0],pa[1],pa[2]: points on line 3 and pb[0],pb[1],pb[2]: points on line 4
203 // Next: Consider x, y and z to be less than cuts[0], cuts[1] and cuts[2], respectively
204 if(TMath::Abs(hphi1-hphi4)<phicut && TMath::Abs(hphi3-hphi2)<phicut) {
205 CalculateLine(p1, p4, p3, p2, pa, pb);
206 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]){
207 distance = (TMath::Sqrt(pow((pa[0]-pb[0]),2) + pow((pa[1]-pb[1]),2) + pow((pa[2]-pb[2]),2)));
208 if(distance<distancecut){
209 hx->Fill(pa[0]); hy->Fill(pa[1]); hz->Fill(pa[2]);
210 hx->Fill(pb[0]); hy->Fill(pb[1]); hz->Fill(pb[2]);
211 ncontr++;
212 }
213 }
214 }
215 }
216 }
217
218 Int_t maxbinx = hx->GetMaximumBin();
219 Int_t maxbiny = hy->GetMaximumBin();
220 Int_t maxbinz = hz->GetMaximumBin();
221 pos[0] = ilow + ((ihigh-ilow)/ibin)*maxbinx;
222 pos[1] = ilow + ((ihigh-ilow)/ibin)*maxbiny;
223 pos[2] = ilowz + ((ihighz-ilowz)/ibinz)*maxbinz;
224 hx->Delete();
225 hy->Delete();
226 hz->Delete();
227}
228
229void AliITSVertexer3DTapan::CalculateVertex3d2(Double_t pos[3], Float_t cuts[3], Int_t &ncontr, Double_t sigpos[3]) {
230 //
231 // This function reconstructs second two steps of vertex
232 //
233
234 Double_t p1[4], p2[4], p3[4], p4[4];
235 Double_t pa[3], pb[3];
236 Double_t hphi1, hphi2, hphi3, hphi4;
237
238 ncontr = 0;
239 Float_t phicut = 0.3;
240 Double_t distance; Float_t distancecut = 1.0;
241
242 Double_t vertx =0.; Double_t verty =0.; Double_t vertz =0.;
243 Double_t vertx2 =0.; Double_t verty2 =0.; Double_t vertz2 =0.;
244
245 for (Int_t ip1=0; ip1<ficlu1; ip1++) {
246 // Two points on layer1: p1 and p3
247 p1[0] = fX1[ip1]; p1[1] = fY1[ip1]; p1[2] = fZ1[ip1];
248 p3[0] = fX1[ip1+1]; p3[1] = fY1[ip1+1]; p3[2] = fZ1[ip1+1];
249 hphi1 = fPhi1[ip1]; hphi3 = fPhi1[ip1+1];
250
251 for (Int_t ip2=0; ip2<ficlu2; ip2++) {
252 // Two points on layer 2: p2 and p4
253 p2[0] = fX2[ip2]; p2[1] = fY2[ip2]; p2[2] = fZ2[ip2];
254 p4[0] = fX2[ip2+1]; p4[1] = fY2[ip2+1]; p4[2] = fZ2[ip2+1];
255 hphi2 = fPhi2[ip2]; hphi4 = fPhi2[ip2+1];
256
257 // First line is formed by p1-p2 and second line by p3-p4
258 // We find two points on each line which form the closest distance of the two lines
259 // 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
260 // Next: Consider x, y and z to be less than cuts[0], cuts[1] and cuts[2], respectively
261
262 if(TMath::Abs(hphi1-hphi2)<phicut && TMath::Abs(hphi3-hphi4)<phicut){
263 CalculateLine(p1, p2, p3, p4, pa, pb);
264
265 // We consider the points where x, y and z points are less than xcut, ycut and zcut, respectively
266 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]){
267 distance = (TMath::Sqrt(pow((pa[0]-pb[0]),2) + pow((pa[1]-pb[1]),2) + pow((pa[2]-pb[2]),2)));
268 if(distance<distancecut){
269 ncontr++;
270 vertx = vertx + pa[0]; verty = verty + pa[1]; vertz = vertz + pa[2];
271 vertx2 = vertx2 + pa[0]*pa[0]; verty2 = verty2 + pa[1]*pa[1]; vertz2 = vertz2 + pa[2]*pa[2];
272 ncontr++;
273 vertx = vertx + pb[0]; verty = verty + pb[1]; vertz = vertz + pb[2];
274 vertx2 = vertx2 + pb[0]*pb[0]; verty2 = verty2 + pb[1]*pb[1]; vertz2 = vertz2 + pb[2]*pb[2];
275 }
276 }
277 }
278
279 // Third line is formed by p1-p4 and fourth line by p3-p2
280 // We find two points on each line which form the closest distance of the two lines
281 // 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
282 // Next: Consider x, y and z to be less than cuts[0], cuts[1] and cuts[2], respectively
283 if(TMath::Abs(hphi1-hphi4)<phicut && TMath::Abs(hphi3-hphi2)<phicut) {
284
285 CalculateLine(p1, p4, p3, p2, pa, pb);
286 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]){
287 distance = (TMath::Sqrt(pow((pa[0]-pb[0]),2) + pow((pa[1]-pb[1]),2) + pow((pa[2]-pb[2]),2)));
288 if(distance<distancecut){
289 ncontr++;
290 vertx = vertx + pa[0]; verty = verty + pa[1]; vertz = vertz + pa[2];
291 vertx2 = vertx2 + pa[0]*pa[0]; verty2 = verty2 + pa[1]*pa[1]; vertz2 = vertz2 + pa[2]*pa[2];
292 ncontr++;
293 vertx = vertx + pb[0]; verty = verty + pb[1]; vertz = vertz + pb[2];
294 vertx2 = vertx2 + pb[0]*pb[0]; verty2 = verty2 + pb[1]*pb[1]; vertz2 = vertz2 + pb[2]*pb[2];
295 }
296 }
297 }
298 }
299 }
300
301 if(ncontr>0){
302 pos[0] = vertx/ncontr; pos[1] = verty/ncontr; pos[2] = vertz/ncontr;
303 vertx2 = vertx2/ncontr; verty2 = verty2/ncontr; vertz2 = vertz2/ncontr;
304 sigpos[0] = TMath::Sqrt(vertx2 - pos[0]*pos[0]);
305 sigpos[1] = TMath::Sqrt(verty2 - pos[1]*pos[1]);
306 sigpos[2] = TMath::Sqrt(vertz2 - pos[2]*pos[2]);
307 }
308 ncontr = ncontr/2;
309}
310
311void AliITSVertexer3DTapan::CalculatePhi(Float_t fx, Float_t fy, Float_t & phi)
312{
313 //calculates phi
314 Float_t ybyx, phi1;
315 const Float_t kradian = 180./3.141592654;
316
317 if(fx==0.)
318 {
319 if(fy>0.) phi = 90.;
320 if(fy<0.) phi = 270.;
321 }
322 if(fx != 0.)
323 {
324 ybyx = fy/fx;
325 if(ybyx < 0) ybyx = - ybyx;
326 phi1 = TMath::ATan(ybyx)*kradian;
327 if(fx > 0 && fy > 0) phi = phi1; // 1st Quadrant
328 if(fx < 0 && fy > 0) phi = 180 - phi1; // 2nd Quadrant
329 if(fx < 0 && fy < 0) phi = 180 + phi1; // 3rd Quadrant
330 if(fx > 0 && fy < 0) phi = 360 - phi1; // 4th Quadrant
331
332 }
333 phi = phi/kradian;
334}
335
336void 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{
337 //calculates line
338 Double_t p13x, p13y, p13z;
339 Double_t p21x, p21y, p21z;
340 Double_t p43x, p43y, p43z;
341 Double_t d1343, d4321, d1321, d4343, d2121;
342 Double_t numer, denom;
343 Double_t mua, mub;
344 mua = 0.; mub = 0.;
345
346 p13x = p1[0] - p3[0];
347 p13y = p1[1] - p3[1];
348 p13z = p1[2] - p3[2];
349
350 p21x = p2[0] - p1[0];
351 p21y = p2[1] - p1[1];
352 p21z = p2[2] - p1[2];
353
354 p43x = p4[0] - p3[0];
355 p43y = p4[1] - p3[1];
356 p43z = p4[2] - p3[2];
357
358 d1343 = p13x * p43x + p13y * p43y + p13z * p43z;
359 d4321 = p43x * p21x + p43y * p21y + p43z * p21z;
360 d1321 = p13x * p21x + p13y * p21y + p13z * p21z;
361 d4343 = p43x * p43x + p43y * p43y + p43z * p43z;
362 d2121 = p21x * p21x + p21y * p21y + p21z * p21z;
363
364 denom = d2121 * d4343 - d4321 * d4321;
365 numer = d1343 * d4321 - d1321 * d4343;
366
367 if(denom>0) mua = numer / denom;
368 if(d4343>0) mub = (d1343 + d4321 * (mua)) / d4343;
369
370 pa[0] = p1[0] + mua * p21x;
371 pa[1] = p1[1] + mua * p21y;
372 pa[2] = p1[2] + mua * p21z;
373
374 pb[0] = p3[0] + mub * p43x;
375 pb[1] = p3[1] + mub * p43y;
376 pb[2] = p3[2] + mub * p43z;
377}
378