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5b3a5a5d | 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 | **************************************************************************/ | |
15 | ||
88cb7938 | 16 | /* $Id$ */ |
5b3a5a5d | 17 | |
18 | // from AliRoot | |
19 | #include "AliFastGlauber.h" | |
20 | // from root | |
21 | #include <TH1F.h> | |
22 | #include <TF1.h> | |
23 | #include <TF2.h> | |
24 | #include <TCanvas.h> | |
25 | #include <TRandom.h> | |
26 | #include <TFile.h> | |
27 | ||
28 | ClassImp(AliFastGlauber) | |
29 | ||
2a103154 | 30 | TF1* AliFastGlauber::fWSb = NULL; |
31 | TF2* AliFastGlauber::fWSbz = NULL; | |
32 | TF1* AliFastGlauber::fWSz = NULL; | |
33 | TF1* AliFastGlauber::fWSta = NULL; | |
34 | TF2* AliFastGlauber::fWStarfi = NULL; | |
35 | TF2* AliFastGlauber::fWAlmond = NULL; | |
36 | TF1* AliFastGlauber::fWStaa = NULL; | |
37 | TF1* AliFastGlauber::fWSgeo = NULL; | |
38 | TF1* AliFastGlauber::fWSbinary = NULL; | |
39 | TF1* AliFastGlauber::fWSN = NULL; | |
40 | TF1* AliFastGlauber::fWPathLength0 = NULL; | |
41 | TF1* AliFastGlauber::fWPathLength = NULL; | |
42 | TF1* AliFastGlauber::fWEnergyDensity = NULL; | |
43 | TF1* AliFastGlauber::fWIntRadius = NULL; | |
44 | Float_t AliFastGlauber::fbMax = 0.; | |
5b3a5a5d | 45 | |
46 | AliFastGlauber::AliFastGlauber() | |
47 | { | |
48 | // Default Constructor | |
49 | // | |
50 | // Defaults for Pb | |
51 | SetWoodSaxonParameters(6.624, 0.549, 0.00, 7.69e-4); | |
52 | SetHardCrossSection(); | |
53 | SetMaxImpact(); | |
54 | } | |
55 | ||
56 | void AliFastGlauber::Init(Int_t mode) | |
57 | { | |
58 | // Initialisation | |
59 | // | |
60 | // Wood-Saxon | |
61 | // | |
62 | fWSb = new TF1("WSb", WSb, 0, fbMax, 4); | |
63 | fWSb->SetParameter(0, fWSr0); | |
64 | fWSb->SetParameter(1, fWSd); | |
65 | fWSb->SetParameter(2, fWSw); | |
66 | fWSb->SetParameter(3, fWSn); | |
67 | ||
68 | fWSbz = new TF2("WSbz", WSbz, 0, fbMax, 4); | |
69 | fWSbz->SetParameter(0, fWSr0); | |
70 | fWSbz->SetParameter(1, fWSd); | |
71 | fWSbz->SetParameter(2, fWSw); | |
72 | fWSbz->SetParameter(3, fWSn); | |
73 | ||
74 | fWSz = new TF1("WSz", WSz, 0, fbMax, 5); | |
75 | fWSz->SetParameter(0, fWSr0); | |
76 | fWSz->SetParameter(1, fWSd); | |
77 | fWSz->SetParameter(2, fWSw); | |
78 | fWSz->SetParameter(3, fWSn); | |
79 | ||
80 | // | |
81 | // Thickness | |
82 | // | |
83 | fWSta = new TF1("WSta", WSta, 0., fbMax, 0); | |
84 | ||
85 | // | |
86 | // Overlap Kernel | |
87 | // | |
88 | fWStarfi = new TF2("WStarfi", WStarfi, 0., fbMax, 0., TMath::Pi(), 1); | |
89 | fWStarfi->SetParameter(0, 0.); | |
90 | fWStarfi->SetNpx(200); | |
91 | fWStarfi->SetNpy(20); | |
92 | // | |
f3a04204 | 93 | // Almond shaped interaction region |
94 | // | |
95 | fWAlmond = new TF2("WAlmond", WAlmond, -fbMax, fbMax, -fbMax, fbMax, 1); | |
96 | fWAlmond->SetParameter(0, 0.); | |
97 | fWAlmond->SetNpx(200); | |
98 | fWAlmond->SetNpy(200); | |
99 | // | |
100 | // Path Length as a function of Phi | |
101 | // | |
102 | fWPathLength0 = new TF1("WPathLength0", WPathLength0, -TMath::Pi(), TMath::Pi(), 1); | |
103 | fWPathLength0->SetParameter(0, 0.); | |
104 | fWPathLength = new TF1("WPathLength", WPathLength, -TMath::Pi(), TMath::Pi(), 2); | |
105 | // Impact Parameter | |
106 | fWPathLength->SetParameter(0, 0.); | |
107 | // Number of interactions used for average | |
108 | fWPathLength->SetParameter(1, 1000.); | |
109 | ||
110 | fWIntRadius = new TF1("WIntRadius", WIntRadius, 0., fbMax, 1); | |
2a103154 | 111 | fWIntRadius->SetParameter(0, 0.); |
112 | ||
113 | ||
f3a04204 | 114 | // |
5b3a5a5d | 115 | // Overlap |
116 | // | |
117 | if (! mode) { | |
118 | fWStaa = new TF1("WStaa", WStaa, 0., fbMax, 0); | |
119 | fWStaa->SetNpx(100); | |
120 | } else { | |
121 | TFile* f = new TFile("$(ALICE_ROOT)/FASTSIM/data/glauberPbPb.root"); | |
122 | fWStaa = (TF1*) f->Get("WStaa"); | |
123 | } | |
124 | ||
2a103154 | 125 | // |
126 | fWEnergyDensity = new TF1("WEnergyDensity", WEnergyDensity, 0., 2. * fWSr0, 1); | |
127 | fWEnergyDensity->SetParameter(0, fWSr0 + 1.); | |
128 | ||
5b3a5a5d | 129 | // |
130 | // Geometrical Cross-Section | |
131 | // | |
132 | fWSgeo = new TF1("WSgeo", WSgeo, 0., fbMax, 0); | |
133 | fWSgeo->SetNpx(100); | |
134 | // | |
135 | // Hard cross section (~ binary collisions) | |
136 | // | |
137 | fWSbinary = new TF1("WSbinary", WSbinary, 0., fbMax, 1); | |
138 | fWSbinary->SetParameter(0, fSigmaHard); // mb | |
139 | fWSbinary->SetNpx(100); | |
140 | // | |
141 | // Hard collisions per event | |
142 | // | |
143 | fWSN = new TF1("WSN", WSN, 0., fbMax, 1); | |
144 | fWSN->SetNpx(100); | |
145 | } | |
146 | ||
147 | void AliFastGlauber::DrawWSb() | |
148 | { | |
149 | // | |
150 | // Draw Wood-Saxon Nuclear Density Function | |
151 | // | |
152 | TCanvas *c1 = new TCanvas("c1","Wood Saxon",400,10,600,700); | |
153 | c1->cd(); | |
154 | fWSb->Draw(); | |
155 | } | |
156 | ||
157 | void AliFastGlauber::DrawOverlap() | |
158 | { | |
159 | // | |
160 | // Draw Overlap Function | |
161 | // | |
162 | TCanvas *c2 = new TCanvas("c2","Overlap",400,10,600,700); | |
163 | c2->cd(); | |
164 | fWStaa->Draw(); | |
165 | } | |
166 | ||
167 | void AliFastGlauber::DrawThickness() | |
168 | { | |
169 | // | |
170 | // Draw Thickness Function | |
171 | // | |
172 | TCanvas *c3 = new TCanvas("c3","Thickness",400,10,600,700); | |
173 | c3->cd(); | |
174 | fWSta->Draw(); | |
175 | } | |
176 | ||
177 | void AliFastGlauber::DrawGeo() | |
178 | { | |
179 | // | |
180 | // Draw Geometrical Cross-Section | |
181 | // | |
182 | TCanvas *c3 = new TCanvas("c3","Geometrical Cross-Section",400,10,600,700); | |
183 | c3->cd(); | |
184 | fWSgeo->Draw(); | |
185 | } | |
186 | ||
187 | void AliFastGlauber::DrawBinary() | |
188 | { | |
189 | // | |
190 | // Draw Wood-Saxon Nuclear Density Function | |
191 | // | |
192 | TCanvas *c4 = new TCanvas("c4","Binary Cross-Section",400,10,600,700); | |
193 | c4->cd(); | |
194 | fWSbinary->Draw(); | |
195 | } | |
196 | ||
197 | void AliFastGlauber::DrawN() | |
198 | { | |
199 | // | |
200 | // Draw Binaries per event | |
201 | // | |
202 | TCanvas *c5 = new TCanvas("c5","Binaries per event",400,10,600,700); | |
203 | c5->cd(); | |
204 | fWSN->Draw(); | |
205 | } | |
206 | ||
f3a04204 | 207 | void AliFastGlauber::DrawKernel(Double_t b) |
5b3a5a5d | 208 | { |
209 | // | |
210 | // Draw Kernel | |
211 | // | |
212 | TCanvas *c6 = new TCanvas("c6","Kernel",400,10,600,700); | |
213 | c6->cd(); | |
f3a04204 | 214 | fWStarfi->SetParameter(0, b); |
5b3a5a5d | 215 | fWStarfi->Draw(); |
216 | } | |
217 | ||
f3a04204 | 218 | void AliFastGlauber::DrawAlmond(Double_t b) |
219 | { | |
220 | // | |
2a103154 | 221 | // Draw Interaction Almond |
f3a04204 | 222 | // |
223 | TCanvas *c7 = new TCanvas("c7","Almond",400,10,600,700); | |
224 | c7->cd(); | |
225 | fWAlmond->SetParameter(0, b); | |
226 | fWAlmond->Draw(); | |
227 | } | |
228 | ||
229 | void AliFastGlauber::DrawPathLength0(Double_t b) | |
230 | { | |
231 | // | |
2a103154 | 232 | // Draw Path Length |
f3a04204 | 233 | // |
234 | TCanvas *c8 = new TCanvas("c8","Path Length",400,10,600,700); | |
235 | c8->cd(); | |
236 | fWPathLength0->SetParameter(0, b); | |
237 | fWPathLength0->SetMinimum(0.); | |
238 | fWPathLength0->SetMaximum(10.); | |
239 | fWPathLength0->Draw(); | |
240 | } | |
241 | ||
242 | void AliFastGlauber::DrawPathLength(Double_t b , Int_t ni) | |
243 | { | |
244 | // | |
2a103154 | 245 | // Draw Path Length |
f3a04204 | 246 | // |
247 | TCanvas *c9 = new TCanvas("c9","Path Length",400,10,600,700); | |
248 | c9->cd(); | |
249 | fWAlmond->SetParameter(0, b); | |
250 | ||
251 | fWPathLength->SetParameter(0, b); | |
252 | fWPathLength->SetParameter(1, Double_t (ni)); | |
253 | fWPathLength->SetMinimum(0.); | |
254 | fWPathLength->SetMaximum(10.); | |
255 | fWPathLength->Draw(); | |
256 | } | |
257 | ||
258 | void AliFastGlauber::DrawIntRadius(Double_t b) | |
259 | { | |
260 | // | |
2a103154 | 261 | // Draw Interaction Radius |
f3a04204 | 262 | // |
263 | TCanvas *c10 = new TCanvas("c10","Interaction Radius",400,10,600,700); | |
264 | c10->cd(); | |
265 | fWIntRadius->SetParameter(0, b); | |
266 | fWIntRadius->SetMinimum(0.); | |
267 | fWIntRadius->Draw(); | |
268 | } | |
269 | ||
2a103154 | 270 | void AliFastGlauber::DrawEnergyDensity() |
271 | { | |
272 | // | |
273 | // Draw energy density | |
274 | // | |
275 | TCanvas *c11 = new TCanvas("c11","Energy Density",400, 10, 600, 700); | |
276 | c11->cd(); | |
277 | fWEnergyDensity->SetMinimum(0.); | |
278 | fWEnergyDensity->Draw(); | |
279 | } | |
280 | ||
5b3a5a5d | 281 | Double_t AliFastGlauber::WSb(Double_t* x, Double_t* par) |
282 | { | |
283 | // | |
284 | // Woods-Saxon Parameterisation | |
285 | // as a function of radius | |
286 | // | |
287 | Double_t xx = x[0]; | |
288 | Double_t r0 = par[0]; | |
289 | Double_t d = par[1]; | |
290 | Double_t w = par[2]; | |
291 | Double_t n = par[3]; | |
292 | ||
293 | Double_t y = n * (1.+w*(xx/r0)*(xx/r0))/(1.+TMath::Exp((xx-r0)/d)); | |
2a103154 | 294 | |
5b3a5a5d | 295 | return y; |
296 | } | |
297 | ||
298 | Double_t AliFastGlauber::WSbz(Double_t* x, Double_t* par) | |
299 | { | |
300 | // | |
301 | // Wood Saxon Parameterisation | |
302 | // as a function of z and b | |
303 | // | |
304 | Double_t bb = x[0]; | |
305 | Double_t zz = x[1]; | |
306 | Double_t r0 = par[0]; | |
307 | Double_t d = par[1]; | |
308 | Double_t w = par[2]; | |
309 | Double_t n = par[3]; | |
310 | Double_t xx = TMath::Sqrt(bb*bb+zz*zz); | |
311 | Double_t y = n * (1.+w*(xx/r0)*(xx/r0))/(1.+TMath::Exp((xx-r0)/d)); | |
2a103154 | 312 | |
5b3a5a5d | 313 | return y; |
314 | } | |
315 | ||
316 | Double_t AliFastGlauber::WSz(Double_t* x, Double_t* par) | |
317 | { | |
318 | // | |
319 | // Wood Saxon Parameterisation | |
320 | // as a function of z for fixed b | |
321 | // | |
322 | Double_t bb = par[4]; | |
323 | Double_t zz = x[0]; | |
324 | Double_t r0 = par[0]; | |
325 | Double_t d = par[1]; | |
326 | Double_t w = par[2]; | |
327 | Double_t n = par[3]; | |
328 | Double_t xx = TMath::Sqrt(bb*bb+zz*zz); | |
329 | Double_t y = n * (1.+w*(xx/r0)*(xx/r0))/(1.+TMath::Exp((xx-r0)/d)); | |
2a103154 | 330 | |
5b3a5a5d | 331 | return y; |
332 | } | |
333 | ||
f86dad79 | 334 | Double_t AliFastGlauber::WSta(Double_t* x, Double_t* /*par*/) |
5b3a5a5d | 335 | { |
336 | // | |
337 | // Thickness function | |
338 | // | |
339 | Double_t b = x[0]; | |
340 | fWSz->SetParameter(4, b); | |
341 | Double_t y = 2. * fWSz->Integral(0., fbMax); | |
342 | return y; | |
343 | } | |
344 | ||
345 | ||
346 | ||
347 | Double_t AliFastGlauber::WStarfi(Double_t* x, Double_t* par) | |
348 | { | |
349 | // | |
350 | // Kernel for overlap function | |
351 | // | |
352 | Double_t b = par[0]; | |
353 | Double_t r1 = x[0]; | |
354 | Double_t phi = x[1]; | |
355 | Double_t r2 = TMath::Sqrt(r1 * r1 + b * b - 2. * r1 * b * TMath::Cos(phi)); | |
356 | Double_t y = r1 * fWSta->Eval(r1) * fWSta->Eval(r2); | |
357 | return y; | |
358 | } | |
359 | ||
360 | ||
f3a04204 | 361 | Double_t AliFastGlauber::WAlmond(Double_t* x, Double_t* par) |
362 | { | |
363 | // | |
364 | // Almond shaped interaction region | |
365 | // | |
366 | Double_t b = par[0]; | |
367 | Double_t xx = x[0] + b/2.; | |
368 | Double_t yy = x[1]; | |
369 | Double_t r1 = TMath::Sqrt(xx * xx + yy * yy); | |
370 | Double_t phi = TMath::ATan2(yy,xx); | |
371 | ||
372 | Double_t r2 = TMath::Sqrt(r1 * r1 + b * b - 2. * r1 * b * TMath::Cos(phi)); | |
373 | // | |
374 | // Interaction probability calculated as product of thicknesses | |
375 | // | |
376 | Double_t y = fWSta->Eval(r1) * fWSta->Eval(r2); | |
377 | return y; | |
378 | } | |
379 | ||
380 | Double_t AliFastGlauber::WIntRadius(Double_t* x, Double_t* par) | |
381 | { | |
382 | // | |
383 | // Average radius at which interaction takes place | |
384 | // | |
385 | // Radius in the Almond | |
386 | Double_t r = x[0]; | |
387 | // Impact parameter | |
388 | Double_t b = par[0]; | |
389 | fWAlmond->SetParameter(0, b); | |
390 | // Steps in phi | |
391 | Double_t dphi = 2. * TMath::Pi() / 100.; | |
392 | // Average over phi | |
393 | Double_t phi = 0.; | |
394 | Double_t y = 0.; | |
395 | ||
396 | for (Int_t i = 0; i < 100; i++) { | |
397 | Double_t xx = r * TMath::Cos(phi); | |
398 | Double_t yy = r * TMath::Sin(phi); | |
399 | y += fWAlmond->Eval(xx,yy); | |
400 | phi += dphi; | |
401 | } // phi loop | |
402 | // Result multiplied by Jacobian (2 pi r) | |
403 | return (2. * TMath::Pi() * y * r / 100.); | |
404 | } | |
405 | ||
406 | Double_t AliFastGlauber::WPathLength0(Double_t* x, Double_t* par) | |
407 | { | |
408 | // | |
409 | // Path Length as a function of phi for interaction point fixed at (0,0) | |
410 | // | |
411 | // | |
412 | // Steps in r | |
413 | const Int_t np = 100; | |
414 | const Double_t dr = fbMax/Double_t(np); | |
415 | // Impact parameter | |
416 | Double_t b = par[0]; | |
417 | // Phi direction in Almond | |
418 | Double_t phi0 = x[0]; | |
419 | Double_t r = 0.; | |
420 | Double_t rw = 0.; | |
421 | Double_t w = 0.; | |
422 | // Step along radial direction phi | |
423 | for (Int_t i = 0; i < np; i++) { | |
424 | // | |
425 | // Transform into target frame | |
426 | // | |
427 | Double_t xx = r * TMath::Cos(phi0) + b / 2.; | |
428 | Double_t yy = r * TMath::Sin(phi0); | |
429 | Double_t phi = TMath::ATan2(yy, xx); | |
430 | ||
431 | Double_t r1 = TMath::Sqrt(xx * xx + yy * yy); | |
432 | // Radius in projectile frame | |
433 | Double_t r2 = TMath::Sqrt(r1 * r1 + b * b - 2. * r1 * b * TMath::Cos(phi)); | |
434 | Double_t y = fWSta->Eval(r1) * fWSta->Eval(r2); | |
435 | ||
436 | rw += y * r; | |
437 | w += y; | |
438 | r += dr; | |
439 | } // radial steps | |
440 | // | |
441 | // My length definition (is exact for hard sphere) | |
442 | return (2. * rw / w); | |
443 | } | |
444 | ||
445 | Double_t AliFastGlauber::WPathLength(Double_t* x, Double_t* par) | |
446 | { | |
447 | // | |
448 | // Path Length as a function of phi | |
449 | // Interaction point from random distribution | |
450 | // | |
451 | // | |
452 | // r-steps | |
453 | // | |
454 | const Int_t np = 100; | |
455 | const Double_t dr = fbMax/Double_t(np); | |
456 | // Number of interactions | |
457 | const Int_t npi = Int_t (par[1]); | |
458 | ||
459 | // | |
460 | // Impact parameter | |
461 | Double_t b = par[0]; | |
462 | // Phi direction | |
463 | Double_t phi0 = x[0]; | |
464 | ||
465 | printf("phi0 %f \n", phi0); | |
466 | ||
467 | // Path length | |
468 | Double_t l = 0.; | |
469 | ||
470 | for (Int_t in = 0; in < npi; in ++) { | |
471 | Double_t rw = 0.; | |
472 | Double_t w = 0.; | |
473 | ||
474 | // Interaction point | |
475 | Double_t x0, y0; | |
476 | fWAlmond->GetRandom2(x0, y0); | |
477 | // Initial radius | |
478 | Double_t r0 = TMath::Sqrt(x0 * x0 + y0 * y0); | |
479 | Int_t nps = Int_t ((fbMax - r0)/dr) - 1; | |
480 | ||
481 | Double_t r = 0.; | |
482 | // Radial steps | |
483 | for (Int_t i = 0; (i < nps ); i++) { | |
484 | ||
485 | // Transform into target frame | |
486 | Double_t xx = x0 + r * TMath::Cos(phi0) + b / 2.; | |
487 | Double_t yy = y0 + r * TMath::Sin(phi0); | |
488 | Double_t phi = TMath::ATan2(yy, xx); | |
489 | Double_t r1 = TMath::Sqrt(xx * xx + yy * yy); | |
490 | // Radius in projectile frame | |
491 | Double_t r2 = TMath::Sqrt(r1 * r1 + b * b - 2. * r1 * b * TMath::Cos(phi)); | |
492 | Double_t y = fWSta->Eval(r1) * fWSta->Eval(r2); | |
493 | ||
494 | rw += y * r; | |
495 | w += y; | |
496 | r += dr; | |
497 | } // steps | |
498 | // Average over interactions | |
499 | l += 2. * rw / w; | |
500 | } // interactions | |
501 | return (l / Double_t(npi)); | |
502 | } | |
503 | ||
f86dad79 | 504 | Double_t AliFastGlauber::WStaa(Double_t* x, Double_t* /*par*/) |
5b3a5a5d | 505 | { |
506 | // | |
507 | // Overlap function | |
508 | // | |
509 | Double_t b = x[0]; | |
510 | fWStarfi->SetParameter(0, b); | |
511 | /* | |
512 | Double_t al[2]; | |
513 | Double_t bl[2]; | |
514 | al[0] = 0.; | |
515 | al[1] = 0.; | |
516 | bl[0] = 6.6; | |
517 | bl[1] = TMath::Pi(); | |
518 | Double_t err; | |
519 | ||
520 | Double_t y = 2. * fWStarfi->IntegralMultiple(2, al, bl, 0.001, err); | |
521 | printf("WStaa: %f %f %f\n", b, y, err); | |
522 | */ | |
523 | // | |
524 | // MC Integration | |
525 | // | |
526 | Double_t y = 0; | |
527 | for (Int_t i = 0; i < 100000; i++) | |
528 | { | |
529 | Double_t phi = TMath::Pi() * gRandom->Rndm(); | |
530 | Double_t b1 = fbMax * gRandom->Rndm(); | |
531 | y += fWStarfi->Eval(b1, phi); | |
532 | } | |
533 | y *= 2. * 0.1 * 208. * 208. * TMath::Pi() * fbMax / 100000.; | |
534 | return y; | |
535 | } | |
536 | ||
f86dad79 | 537 | Double_t AliFastGlauber::WSgeo(Double_t* x, Double_t* /*par*/) |
5b3a5a5d | 538 | { |
539 | // | |
540 | // Geometrical Cross-Section | |
541 | // | |
542 | Double_t b = x[0]; | |
543 | Double_t taa = fWStaa->Eval(b); | |
544 | const Double_t sigma = 55.6; // mbarn | |
545 | ||
546 | Double_t y = 2. * TMath::Pi() * b * (1. - TMath::Exp(- sigma * taa)); // fm | |
547 | return y; | |
548 | } | |
549 | ||
550 | ||
551 | Double_t AliFastGlauber::WSbinary(Double_t* x, Double_t* par) | |
552 | { | |
553 | // | |
c2140715 | 554 | // Number of binary collisions |
5b3a5a5d | 555 | // |
556 | Double_t b = x[0]; | |
557 | Double_t sigma = par[0]; | |
558 | Double_t taa = fWStaa->Eval(b); | |
559 | ||
560 | Double_t y = 2. * TMath::Pi() * b * sigma * taa; // fm | |
561 | return y; | |
562 | } | |
563 | ||
f86dad79 | 564 | Double_t AliFastGlauber::WSN(Double_t* x, Double_t* /*par*/) |
5b3a5a5d | 565 | { |
566 | // | |
c2140715 | 567 | // Number of hard processes per event |
5b3a5a5d | 568 | // |
569 | Double_t b = x[0]; | |
88cb7938 | 570 | Double_t y = fWSbinary->Eval(b)/fWSgeo->Eval(b); |
5b3a5a5d | 571 | return y; |
572 | } | |
573 | ||
2a103154 | 574 | Double_t AliFastGlauber::WEnergyDensity(Double_t* x, Double_t* par) |
575 | { | |
576 | // | |
577 | // Initial energy density as a function of the impact parameter | |
578 | // | |
579 | Double_t b = x[0]; | |
580 | Double_t rA = par[0]; | |
581 | ||
582 | Double_t saa = (TMath::Pi() - 2. * TMath::ASin(b/ 2./ rA)) * rA * rA - b * TMath::Sqrt(rA * rA - b * b/ 4.); | |
583 | Double_t taa = fWStaa->Eval(b); | |
584 | ||
585 | return (taa/saa); | |
586 | } | |
587 | ||
5b3a5a5d | 588 | void AliFastGlauber::SimulateTrigger(Int_t n) |
589 | { | |
590 | // | |
591 | // Simulates Trigger | |
592 | // | |
593 | TH1F* mbtH = new TH1F("mbtH", "MB Trigger b-Distribution", 100, 0., 20.); | |
594 | TH1F* hdtH = new TH1F("hdtH", "Hard Trigger b-Distribution", 100, 0., 20.); | |
595 | TH1F* mbmH = new TH1F("mbmH", "MB Trigger Multiplicity Distribution", 100, 0., 8000.); | |
596 | TH1F* hdmH = new TH1F("hdmH", "Hard Trigger Multiplicity Distribution", 100, 0., 8000.); | |
597 | ||
598 | mbtH->SetXTitle("b [fm]"); | |
599 | hdtH->SetXTitle("b [fm]"); | |
600 | mbmH->SetXTitle("Multiplicity"); | |
601 | hdmH->SetXTitle("Multiplicity"); | |
602 | ||
603 | TCanvas *c0 = new TCanvas("c0","Trigger Simulation",400,10,600,700); | |
604 | c0->Divide(2,1); | |
605 | TCanvas *c1 = new TCanvas("c1","Trigger Simulation",400,10,600,700); | |
606 | c1->Divide(1,2); | |
607 | ||
608 | // | |
609 | // | |
610 | Init(1); | |
611 | for (Int_t iev = 0; iev < n; iev++) | |
612 | { | |
613 | Float_t b, p, mult; | |
614 | GetRandom(b, p, mult); | |
615 | mbtH->Fill(b,1.); | |
616 | hdtH->Fill(b, p); | |
617 | mbmH->Fill(mult, 1.); | |
618 | hdmH->Fill(mult, p); | |
619 | ||
620 | c0->cd(1); | |
621 | mbtH->Draw(); | |
622 | c0->cd(2); | |
623 | hdtH->Draw(); | |
624 | c0->Update(); | |
625 | ||
626 | c1->cd(1); | |
627 | mbmH->Draw(); | |
628 | c1->cd(2); | |
629 | hdmH->Draw(); | |
630 | c1->Update(); | |
631 | } | |
632 | } | |
633 | ||
634 | void AliFastGlauber::GetRandom(Float_t& b, Float_t& p, Float_t& mult) | |
635 | { | |
636 | // | |
637 | // Gives back a random impact parameter, hard trigger probability and multiplicity | |
638 | // | |
639 | b = fWSgeo->GetRandom(); | |
640 | Float_t mu = fWSN->Eval(b); | |
641 | p = 1.-TMath::Exp(-mu); | |
88cb7938 | 642 | mult = 6000./fWSN->Eval(1.) * mu; |
5b3a5a5d | 643 | } |
644 | ||
c2140715 | 645 | void AliFastGlauber::GetRandom(Int_t& bin, Bool_t& hard) |
646 | { | |
647 | // | |
648 | // Gives back a random impact parameter bin, and hard trigger decission | |
649 | // | |
650 | Float_t b = fWSgeo->GetRandom(); | |
651 | Float_t mu = fWSN->Eval(b) * fSigmaHard; | |
652 | Float_t p = 1.-TMath::Exp(-mu); | |
653 | if (b < 5.) { | |
654 | bin = 1; | |
655 | } else if (b < 8.6) { | |
656 | bin = 2; | |
657 | } else if (b < 11.2) { | |
658 | bin = 3; | |
659 | } else if (b < 13.2) { | |
660 | bin = 4; | |
204e011f | 661 | } else if (b < 15.0) { |
c2140715 | 662 | bin = 5; |
204e011f | 663 | } else { |
664 | bin = 6; | |
c2140715 | 665 | } |
666 | ||
667 | hard = kFALSE; | |
668 | ||
669 | Float_t r = gRandom->Rndm(); | |
670 | ||
671 | if (r < p) hard = kTRUE; | |
672 | } | |
673 | ||
674 | ||
5b3a5a5d | 675 | Float_t AliFastGlauber::GetRandomImpactParameter(Float_t bmin, Float_t bmax) |
676 | { | |
677 | // | |
678 | // Gives back a random impact parameter in the range bmin .. bmax | |
679 | // | |
680 | ||
681 | Float_t b = -1.; | |
682 | while(b < bmin || b > bmax) | |
683 | b = fWSgeo->GetRandom(); | |
684 | return b; | |
685 | } | |
686 | ||
687 | Double_t AliFastGlauber::CrossSection(Double_t b1, Double_t b2) | |
688 | { | |
689 | // | |
690 | // Return cross-section integrated from b1 to b2 | |
691 | // | |
692 | ||
693 | return fWSgeo->Integral(b1, b2)/100.; | |
694 | } | |
695 | ||
696 | Double_t AliFastGlauber::FractionOfHardCrossSection(Double_t b1, Double_t b2) | |
697 | { | |
698 | // | |
699 | // Return raction of hard cross-section integrated from b1 to b2 | |
700 | // | |
701 | ||
702 | return fWSbinary->Integral(b1, b2)/fWSbinary->Integral(0., 100.); | |
703 | } | |
704 | ||
705 | ||
706 | Double_t AliFastGlauber::Binaries(Double_t b) | |
707 | { | |
708 | // | |
709 | // Return number of binary collisions normalized to 1 at b=0 | |
710 | // | |
711 | ||
270181a5 | 712 | return fWSN->Eval(b)/fWSN->Eval(0.); |
5b3a5a5d | 713 | } |