[u/mrichter/AliRoot.git] / FASTSIM / AliFastGlauber.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.                  *
 **************************************************************************/

/* $Id$ */

// from AliRoot
#include "AliFastGlauber.h"
// from root
#include <TH1F.h>
#include <TF1.h>
#include <TF2.h>
#include <TCanvas.h>
#include <TRandom.h>
#include <TFile.h>

ClassImp(AliFastGlauber)

TF1*    AliFastGlauber::fWSb      = NULL;     
TF2*    AliFastGlauber::fWSbz     = NULL;    
TF1*    AliFastGlauber::fWSz      = NULL;     
TF1*    AliFastGlauber::fWSta     = NULL;    
TF2*    AliFastGlauber::fWStarfi  = NULL; 
TF1*    AliFastGlauber::fWStaa    = NULL;   
TF1*    AliFastGlauber::fWSgeo    = NULL;   
TF1*    AliFastGlauber::fWSbinary = NULL;   
TF1*    AliFastGlauber::fWSN      = NULL;   
Float_t AliFastGlauber::fbMax     = 0.;

AliFastGlauber::AliFastGlauber()
{
//  Default Constructor
//
//  Defaults for Pb
    SetWoodSaxonParameters(6.624, 0.549, 0.00, 7.69e-4);
    SetHardCrossSection();
    SetMaxImpact();
}

void AliFastGlauber::Init(Int_t mode)
{
// Initialisation
//
//  Wood-Saxon
//
    fWSb = new TF1("WSb", WSb, 0, fbMax, 4);
    fWSb->SetParameter(0, fWSr0);
    fWSb->SetParameter(1, fWSd);
    fWSb->SetParameter(2, fWSw);
    fWSb->SetParameter(3, fWSn);

    fWSbz = new TF2("WSbz", WSbz, 0, fbMax, 4);
    fWSbz->SetParameter(0, fWSr0);
    fWSbz->SetParameter(1, fWSd);
    fWSbz->SetParameter(2, fWSw);
    fWSbz->SetParameter(3, fWSn);

    fWSz = new TF1("WSz", WSz, 0, fbMax, 5);
    fWSz->SetParameter(0, fWSr0);
    fWSz->SetParameter(1, fWSd);
    fWSz->SetParameter(2, fWSw);
    fWSz->SetParameter(3, fWSn);

//
//  Thickness
//
    fWSta = new TF1("WSta", WSta, 0., fbMax, 0);
    
//
//  Overlap Kernel
//
    fWStarfi = new TF2("WStarfi", WStarfi, 0., fbMax, 0., TMath::Pi(), 1);
    fWStarfi->SetParameter(0, 0.);     
    fWStarfi->SetNpx(200);     
    fWStarfi->SetNpy(20);     
//
//  Overlap
//
    if (! mode) {
	fWStaa = new TF1("WStaa", WStaa, 0., fbMax, 0);
	fWStaa->SetNpx(100);
    } else {
	TFile* f = new TFile("$(ALICE_ROOT)/FASTSIM/data/glauberPbPb.root");
	fWStaa = (TF1*) f->Get("WStaa");
    }
    
//
//  Geometrical Cross-Section
//
    fWSgeo = new TF1("WSgeo", WSgeo, 0., fbMax, 0);
    fWSgeo->SetNpx(100);
//
//  Hard cross section (~ binary collisions)
//
    fWSbinary = new TF1("WSbinary", WSbinary, 0., fbMax, 1);
    fWSbinary->SetParameter(0, fSigmaHard); // mb
    fWSbinary->SetNpx(100);
//
// Hard collisions per event
//
    fWSN = new TF1("WSN", WSN, 0., fbMax, 1);
    fWSN->SetNpx(100);
}

void AliFastGlauber::DrawWSb()
{
//
//  Draw Wood-Saxon Nuclear Density Function
//
    TCanvas *c1 = new TCanvas("c1","Wood Saxon",400,10,600,700);
    c1->cd();
    fWSb->Draw();
}

void AliFastGlauber::DrawOverlap()
{
//
//  Draw Overlap Function
//
    TCanvas *c2 = new TCanvas("c2","Overlap",400,10,600,700);
    c2->cd();
    fWStaa->Draw();
}

void AliFastGlauber::DrawThickness()
{
//
//  Draw Thickness Function
//
    TCanvas *c3 = new TCanvas("c3","Thickness",400,10,600,700);
    c3->cd();
    fWSta->Draw();
}

void AliFastGlauber::DrawGeo()
{
//
//  Draw Geometrical Cross-Section
//
    TCanvas *c3 = new TCanvas("c3","Geometrical Cross-Section",400,10,600,700);
    c3->cd();
    fWSgeo->Draw();
}

void AliFastGlauber::DrawBinary()
{
//
//  Draw Wood-Saxon Nuclear Density Function
//
    TCanvas *c4 = new TCanvas("c4","Binary Cross-Section",400,10,600,700);
    c4->cd();
    fWSbinary->Draw();
}

void AliFastGlauber::DrawN()
{
//
//  Draw Binaries per event
//
    TCanvas *c5 = new TCanvas("c5","Binaries per event",400,10,600,700);
    c5->cd();
    fWSN->Draw();
}

void AliFastGlauber::DrawKernel()
{
//
//  Draw Kernel
//
    TCanvas *c6 = new TCanvas("c6","Kernel",400,10,600,700);
    c6->cd();
    fWStarfi->Draw();
}

Double_t AliFastGlauber::WSb(Double_t* x, Double_t* par)
{
//
//  Woods-Saxon Parameterisation
//  as a function of radius
//
    Double_t xx  = x[0];
    Double_t r0  = par[0];
    Double_t d   = par[1];
    Double_t w   = par[2];
    Double_t n   = par[3];
    
    Double_t y  = n * (1.+w*(xx/r0)*(xx/r0))/(1.+TMath::Exp((xx-r0)/d));
    return y;
}

Double_t AliFastGlauber::WSbz(Double_t* x, Double_t* par)
{
//
//  Wood Saxon Parameterisation
//  as a function of z and  b
//
    Double_t bb  = x[0];
    Double_t zz  = x[1];
    Double_t r0  = par[0];
    Double_t d   = par[1];
    Double_t w   = par[2];
    Double_t n   = par[3];
    Double_t xx  = TMath::Sqrt(bb*bb+zz*zz);
    Double_t y  = n * (1.+w*(xx/r0)*(xx/r0))/(1.+TMath::Exp((xx-r0)/d));
    return y;
}

Double_t AliFastGlauber::WSz(Double_t* x, Double_t* par)
{
//
//  Wood Saxon Parameterisation
//  as a function of z for fixed b
//
    Double_t bb  = par[4];
    Double_t zz  = x[0];
    Double_t r0  = par[0];
    Double_t d   = par[1];
    Double_t w   = par[2];
    Double_t n   = par[3];
    Double_t xx  = TMath::Sqrt(bb*bb+zz*zz);
    Double_t y  = n * (1.+w*(xx/r0)*(xx/r0))/(1.+TMath::Exp((xx-r0)/d));
//    if (y < 1.e-6) y = 0;
    return y;
}

Double_t AliFastGlauber::WSta(Double_t* x, Double_t* par)
{
//
//  Thickness function 
//
    Double_t b  = x[0];
    fWSz->SetParameter(4, b);
    Double_t y  = 2. * fWSz->Integral(0., fbMax);
    return y;
}


Double_t AliFastGlauber::WStarfi(Double_t* x, Double_t* par)
{
//
//  Kernel for overlap function
//
    Double_t b    = par[0];
    Double_t r1   = x[0];
    Double_t phi  = x[1];
    Double_t r2   = TMath::Sqrt(r1 * r1 + b * b - 2. * r1 * b * TMath::Cos(phi)); 
    Double_t y    = r1 * fWSta->Eval(r1) * fWSta->Eval(r2);
    return y;
}


Double_t AliFastGlauber::WStaa(Double_t* x, Double_t* par)
{
//
//  Overlap function
//
    Double_t b    = x[0];
    fWStarfi->SetParameter(0, b);
/*
    Double_t al[2];
    Double_t bl[2];
    al[0] = 0.;
    al[1] = 0.;
    bl[0] = 6.6;
    bl[1] = TMath::Pi();
    Double_t err;
    
    Double_t y =  2. * fWStarfi->IntegralMultiple(2, al, bl, 0.001, err);
    printf("WStaa: %f %f %f\n", b, y, err);
*/
//
//  MC Integration
//
    Double_t y = 0;
    for (Int_t i = 0; i < 100000; i++)
    {
	Double_t phi = TMath::Pi() * gRandom->Rndm();
	Double_t b1  = fbMax       * gRandom->Rndm();	
	y += fWStarfi->Eval(b1, phi);
    }
    y *= 2. * 0.1 *  208. * 208. * TMath::Pi() * fbMax / 100000.;
    return y;
}

Double_t AliFastGlauber::WSgeo(Double_t* x, Double_t* par)
{
//
//  Geometrical Cross-Section
//
    Double_t b    = x[0];
    Double_t taa  = fWStaa->Eval(b);
    const Double_t sigma = 55.6; // mbarn
    
    Double_t y    = 2. * TMath::Pi() * b * (1. - TMath::Exp(- sigma * taa)); // fm
    return y;
}


Double_t AliFastGlauber::WSbinary(Double_t* x, Double_t* par)
{
//
//  Number of binary collisions
//
    Double_t b     = x[0];
    Double_t sigma = par[0];
    Double_t taa   = fWStaa->Eval(b);
    
    Double_t y    = 2. * TMath::Pi() * b * sigma * taa; // fm
    return y;
}

Double_t AliFastGlauber::WSN(Double_t* x, Double_t* par)
{
//
//  Number of hard processes per event
//
    Double_t b     = x[0];
    Double_t y     = fWSbinary->Eval(b)/fWSgeo->Eval(b);
    return y;
}

void AliFastGlauber::SimulateTrigger(Int_t n)
{
    //
    //  Simulates Trigger
    //
    TH1F* mbtH = new TH1F("mbtH", "MB Trigger b-Distribution",   100, 0., 20.);
    TH1F* hdtH = new TH1F("hdtH", "Hard Trigger b-Distribution", 100, 0., 20.);   
    TH1F* mbmH = new TH1F("mbmH", "MB Trigger Multiplicity Distribution",   100, 0., 8000.);
    TH1F* hdmH = new TH1F("hdmH", "Hard Trigger Multiplicity Distribution", 100, 0., 8000.);   

    mbtH->SetXTitle("b [fm]");
    hdtH->SetXTitle("b [fm]");    
    mbmH->SetXTitle("Multiplicity");
    hdmH->SetXTitle("Multiplicity");    

    TCanvas *c0 = new TCanvas("c0","Trigger Simulation",400,10,600,700);    
    c0->Divide(2,1);
    TCanvas *c1 = new TCanvas("c1","Trigger Simulation",400,10,600,700);    
    c1->Divide(1,2);

    //
    //
    Init(1);
    for (Int_t iev = 0; iev < n; iev++)
    {
	Float_t b, p, mult;
	GetRandom(b, p, mult);
	mbtH->Fill(b,1.);
	hdtH->Fill(b, p);
	mbmH->Fill(mult, 1.);
	hdmH->Fill(mult, p);

	c0->cd(1);
	mbtH->Draw();
	c0->cd(2);
	hdtH->Draw();	
	c0->Update();

	c1->cd(1);
	mbmH->Draw();
	c1->cd(2);
	hdmH->Draw();	
	c1->Update();
    }
}

void AliFastGlauber::GetRandom(Float_t& b, Float_t& p, Float_t& mult)
{
    //
    // Gives back a random impact parameter, hard trigger probability and multiplicity
    //
	b = fWSgeo->GetRandom();
	Float_t mu = fWSN->Eval(b);
	p = 1.-TMath::Exp(-mu);
	mult = 6000./fWSN->Eval(1.) * mu;
}

void AliFastGlauber::GetRandom(Int_t& bin, Bool_t& hard)
{
    //
    // Gives back a random impact parameter bin, and hard trigger decission
    //
	Float_t b  = fWSgeo->GetRandom();
	Float_t mu = fWSN->Eval(b) * fSigmaHard;
	Float_t p  = 1.-TMath::Exp(-mu);
	if (b < 5.) {
	    bin = 1;
	} else if (b <  8.6) {
	    bin = 2;
	} else if (b < 11.2) {
	    bin = 3;
	} else if (b < 13.2) {
	    bin = 4;
	} else if (b < 15.0) {
	    bin = 5;
	} else {
	    bin = 6;
	}
	
	hard = kFALSE;
	
	Float_t r = gRandom->Rndm();
	
	if (r < p) hard = kTRUE;
}


Float_t  AliFastGlauber::GetRandomImpactParameter(Float_t bmin, Float_t bmax)
{
    //
    // Gives back a random impact parameter in the range bmin .. bmax
    //

    Float_t b = -1.;
    while(b < bmin || b > bmax)
	b = fWSgeo->GetRandom();
    return b;
}

Double_t AliFastGlauber::CrossSection(Double_t b1, Double_t b2)
{
    //
    // Return cross-section integrated from b1 to b2 
    //
    
    return fWSgeo->Integral(b1, b2)/100.;
}

Double_t AliFastGlauber::FractionOfHardCrossSection(Double_t b1, Double_t b2)
{
    //
    // Return raction of hard cross-section integrated from b1 to b2 
    //
    
    return fWSbinary->Integral(b1, b2)/fWSbinary->Integral(0., 100.);
}


Double_t AliFastGlauber::Binaries(Double_t b)
{
    //
    // Return number of binary collisions normalized to 1 at b=0
    //
    
    return fWSN->Eval(b)/fWSN->Eval(0.);
}
Commit	Line	Data
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
	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	TF1* AliFastGlauber::fWStaa = NULL;
	36	TF1* AliFastGlauber::fWSgeo = NULL;
	37	TF1* AliFastGlauber::fWSbinary = NULL;
	38	TF1* AliFastGlauber::fWSN = NULL;
	39	Float_t AliFastGlauber::fbMax = 0.;
	40
	41	AliFastGlauber::AliFastGlauber()
	42	{
	43	// Default Constructor
	44	//
	45	// Defaults for Pb
	46	SetWoodSaxonParameters(6.624, 0.549, 0.00, 7.69e-4);
	47	SetHardCrossSection();
	48	SetMaxImpact();
	49	}
	50
	51	void AliFastGlauber::Init(Int_t mode)
	52	{
	53	// Initialisation
	54	//
	55	// Wood-Saxon
	56	//
	57	fWSb = new TF1("WSb", WSb, 0, fbMax, 4);
	58	fWSb->SetParameter(0, fWSr0);
	59	fWSb->SetParameter(1, fWSd);
	60	fWSb->SetParameter(2, fWSw);
	61	fWSb->SetParameter(3, fWSn);
	62
	63	fWSbz = new TF2("WSbz", WSbz, 0, fbMax, 4);
	64	fWSbz->SetParameter(0, fWSr0);
	65	fWSbz->SetParameter(1, fWSd);
	66	fWSbz->SetParameter(2, fWSw);
	67	fWSbz->SetParameter(3, fWSn);
	68
	69	fWSz = new TF1("WSz", WSz, 0, fbMax, 5);
	70	fWSz->SetParameter(0, fWSr0);
	71	fWSz->SetParameter(1, fWSd);
	72	fWSz->SetParameter(2, fWSw);
	73	fWSz->SetParameter(3, fWSn);
	74
	75	//
	76	// Thickness
	77	//
	78	fWSta = new TF1("WSta", WSta, 0., fbMax, 0);
	79
	80	//
81	// Overlap Kernel
82	//
83	fWStarfi = new TF2("WStarfi", WStarfi, 0., fbMax, 0., TMath::Pi(), 1);
84	fWStarfi->SetParameter(0, 0.);
85	fWStarfi->SetNpx(200);
86	fWStarfi->SetNpy(20);
87	//
88	// Overlap
89	//
90	if (! mode) {
91	fWStaa = new TF1("WStaa", WStaa, 0., fbMax, 0);
92	fWStaa->SetNpx(100);
93	} else {
94	TFile* f = new TFile("$(ALICE_ROOT)/FASTSIM/data/glauberPbPb.root");
95	fWStaa = (TF1*) f->Get("WStaa");
96	}
97
98	//
99	// Geometrical Cross-Section
100	//
101	fWSgeo = new TF1("WSgeo", WSgeo, 0., fbMax, 0);
102	fWSgeo->SetNpx(100);
103	//
104	// Hard cross section (~ binary collisions)
105	//
106	fWSbinary = new TF1("WSbinary", WSbinary, 0., fbMax, 1);
107	fWSbinary->SetParameter(0, fSigmaHard); // mb
108	fWSbinary->SetNpx(100);
109	//
110	// Hard collisions per event
111	//
112	fWSN = new TF1("WSN", WSN, 0., fbMax, 1);
113	fWSN->SetNpx(100);
114	}
115
116	void AliFastGlauber::DrawWSb()
117	{
118	//
119	// Draw Wood-Saxon Nuclear Density Function
120	//
121	TCanvas *c1 = new TCanvas("c1","Wood Saxon",400,10,600,700);
122	c1->cd();
123	fWSb->Draw();
124	}
125
126	void AliFastGlauber::DrawOverlap()
127	{
128	//
129	// Draw Overlap Function
130	//
131	TCanvas *c2 = new TCanvas("c2","Overlap",400,10,600,700);
132	c2->cd();
133	fWStaa->Draw();
134	}
135
136	void AliFastGlauber::DrawThickness()
137	{
138	//
139	// Draw Thickness Function
140	//
141	TCanvas *c3 = new TCanvas("c3","Thickness",400,10,600,700);
142	c3->cd();
143	fWSta->Draw();
144	}
145
146	void AliFastGlauber::DrawGeo()
147	{
148	//
149	// Draw Geometrical Cross-Section
150	//
151	TCanvas *c3 = new TCanvas("c3","Geometrical Cross-Section",400,10,600,700);
152	c3->cd();
153	fWSgeo->Draw();
154	}
155
156	void AliFastGlauber::DrawBinary()
157	{
158	//
159	// Draw Wood-Saxon Nuclear Density Function
160	//
161	TCanvas *c4 = new TCanvas("c4","Binary Cross-Section",400,10,600,700);
162	c4->cd();
163	fWSbinary->Draw();
164	}
165
166	void AliFastGlauber::DrawN()
167	{
168	//
169	// Draw Binaries per event
170	//
171	TCanvas *c5 = new TCanvas("c5","Binaries per event",400,10,600,700);
172	c5->cd();
173	fWSN->Draw();
174	}
175
176	void AliFastGlauber::DrawKernel()
177	{
178	//
179	// Draw Kernel
180	//
181	TCanvas *c6 = new TCanvas("c6","Kernel",400,10,600,700);
182	c6->cd();
183	fWStarfi->Draw();
184	}
185
186	Double_t AliFastGlauber::WSb(Double_t* x, Double_t* par)
187	{
188	//
189	// Woods-Saxon Parameterisation
190	// as a function of radius
191	//
192	Double_t xx = x[0];
193	Double_t r0 = par[0];
194	Double_t d = par[1];
195	Double_t w = par[2];
196	Double_t n = par[3];
197
198	Double_t y = n * (1.+w(xx/r0)(xx/r0))/(1.+TMath::Exp((xx-r0)/d));
199	return y;
200	}
201
202	Double_t AliFastGlauber::WSbz(Double_t* x, Double_t* par)
203	{
204	//
205	// Wood Saxon Parameterisation
206	// as a function of z and b
207	//
208	Double_t bb = x[0];
209	Double_t zz = x[1];
210	Double_t r0 = par[0];
211	Double_t d = par[1];
212	Double_t w = par[2];
213	Double_t n = par[3];
214	Double_t xx = TMath::Sqrt(bbbb+zzzz);
215	Double_t y = n * (1.+w(xx/r0)(xx/r0))/(1.+TMath::Exp((xx-r0)/d));
216	return y;
217	}
218
219	Double_t AliFastGlauber::WSz(Double_t* x, Double_t* par)
220	{
221	//
222	// Wood Saxon Parameterisation
223	// as a function of z for fixed b
224	//
225	Double_t bb = par[4];
226	Double_t zz = x[0];
227	Double_t r0 = par[0];
228	Double_t d = par[1];
229	Double_t w = par[2];
230	Double_t n = par[3];
231	Double_t xx = TMath::Sqrt(bbbb+zzzz);
232	Double_t y = n * (1.+w(xx/r0)(xx/r0))/(1.+TMath::Exp((xx-r0)/d));
233	// if (y < 1.e-6) y = 0;
234	return y;
235	}
236
237	Double_t AliFastGlauber::WSta(Double_t* x, Double_t* par)
238	{
239	//
240	// Thickness function
241	//
242	Double_t b = x[0];
243	fWSz->SetParameter(4, b);
244	Double_t y = 2. * fWSz->Integral(0., fbMax);
245	return y;
246	}
247
248
249
250	Double_t AliFastGlauber::WStarfi(Double_t* x, Double_t* par)
251	{
252	//
253	// Kernel for overlap function
254	//
255	Double_t b = par[0];
256	Double_t r1 = x[0];
257	Double_t phi = x[1];
258	Double_t r2 = TMath::Sqrt(r1 * r1 + b * b - 2. * r1 * b * TMath::Cos(phi));
259	Double_t y = r1 * fWSta->Eval(r1) * fWSta->Eval(r2);
260	return y;
261	}
262
263
264	Double_t AliFastGlauber::WStaa(Double_t* x, Double_t* par)
265	{
266	//
267	// Overlap function
268	//
269	Double_t b = x[0];
270	fWStarfi->SetParameter(0, b);
271	/*
272	Double_t al[2];
273	Double_t bl[2];
274	al[0] = 0.;
275	al[1] = 0.;
276	bl[0] = 6.6;
277	bl[1] = TMath::Pi();
278	Double_t err;
279
280	Double_t y = 2. * fWStarfi->IntegralMultiple(2, al, bl, 0.001, err);
281	printf("WStaa: %f %f %f\n", b, y, err);
282	*/
283	//
284	// MC Integration
285	//
286	Double_t y = 0;
287	for (Int_t i = 0; i < 100000; i++)
288	{
289	Double_t phi = TMath::Pi() * gRandom->Rndm();
290	Double_t b1 = fbMax * gRandom->Rndm();
291	y += fWStarfi->Eval(b1, phi);
292	}
293	y = 2. 0.1 * 208. * 208. * TMath::Pi() * fbMax / 100000.;
294	return y;
295	}
296
297	Double_t AliFastGlauber::WSgeo(Double_t* x, Double_t* par)
298	{
299	//
300	// Geometrical Cross-Section
301	//
302	Double_t b = x[0];
303	Double_t taa = fWStaa->Eval(b);
304	const Double_t sigma = 55.6; // mbarn
305
306	Double_t y = 2. * TMath::Pi() * b * (1. - TMath::Exp(- sigma * taa)); // fm
307	return y;
308	}
309
310
311	Double_t AliFastGlauber::WSbinary(Double_t* x, Double_t* par)
312	{
313	//
c2140715	314	// Number of binary collisions
5b3a5a5d	315	//
	316	Double_t b = x[0];
	317	Double_t sigma = par[0];
	318	Double_t taa = fWStaa->Eval(b);
	319
	320	Double_t y = 2. * TMath::Pi() * b * sigma * taa; // fm
	321	return y;
	322	}
	323
	324	Double_t AliFastGlauber::WSN(Double_t* x, Double_t* par)
	325	{
	326	//
c2140715	327	// Number of hard processes per event
5b3a5a5d	328	//
5b3a5a5d	329	Double_t b = x[0];
88cb7938	330	Double_t y = fWSbinary->Eval(b)/fWSgeo->Eval(b);
5b3a5a5d	331	return y;
	332	}
	333
	334	void AliFastGlauber::SimulateTrigger(Int_t n)
	335	{
	336	//
	337	// Simulates Trigger
	338	//
	339	TH1F* mbtH = new TH1F("mbtH", "MB Trigger b-Distribution", 100, 0., 20.);
	340	TH1F* hdtH = new TH1F("hdtH", "Hard Trigger b-Distribution", 100, 0., 20.);
	341	TH1F* mbmH = new TH1F("mbmH", "MB Trigger Multiplicity Distribution", 100, 0., 8000.);
	342	TH1F* hdmH = new TH1F("hdmH", "Hard Trigger Multiplicity Distribution", 100, 0., 8000.);
	343
	344	mbtH->SetXTitle("b [fm]");
	345	hdtH->SetXTitle("b [fm]");
	346	mbmH->SetXTitle("Multiplicity");
	347	hdmH->SetXTitle("Multiplicity");
	348
	349	TCanvas *c0 = new TCanvas("c0","Trigger Simulation",400,10,600,700);
	350	c0->Divide(2,1);
	351	TCanvas *c1 = new TCanvas("c1","Trigger Simulation",400,10,600,700);
	352	c1->Divide(1,2);
	353
	354	//
	355	//
	356	Init(1);
	357	for (Int_t iev = 0; iev < n; iev++)
	358	{
	359	Float_t b, p, mult;
	360	GetRandom(b, p, mult);
	361	mbtH->Fill(b,1.);
	362	hdtH->Fill(b, p);
	363	mbmH->Fill(mult, 1.);
	364	hdmH->Fill(mult, p);
	365
	366	c0->cd(1);
	367	mbtH->Draw();
	368	c0->cd(2);
	369	hdtH->Draw();
	370	c0->Update();
	371
	372	c1->cd(1);
	373	mbmH->Draw();
	374	c1->cd(2);
	375	hdmH->Draw();
	376	c1->Update();
	377	}
	378	}
	379
	380	void AliFastGlauber::GetRandom(Float_t& b, Float_t& p, Float_t& mult)
	381	{
	382	//
	383	// Gives back a random impact parameter, hard trigger probability and multiplicity
	384	//
	385	b = fWSgeo->GetRandom();
	386	Float_t mu = fWSN->Eval(b);
	387	p = 1.-TMath::Exp(-mu);
88cb7938	388	mult = 6000./fWSN->Eval(1.) * mu;
5b3a5a5d	389	}
5b3a5a5d	390
c2140715	391	void AliFastGlauber::GetRandom(Int_t& bin, Bool_t& hard)
	392	{
	393	//
	394	// Gives back a random impact parameter bin, and hard trigger decission
	395	//
	396	Float_t b = fWSgeo->GetRandom();
	397	Float_t mu = fWSN->Eval(b) * fSigmaHard;
	398	Float_t p = 1.-TMath::Exp(-mu);
	399	if (b < 5.) {
	400	bin = 1;
	401	} else if (b < 8.6) {
	402	bin = 2;
	403	} else if (b < 11.2) {
	404	bin = 3;
	405	} else if (b < 13.2) {
	406	bin = 4;
204e011f	407	} else if (b < 15.0) {
c2140715	408	bin = 5;
204e011f	409	} else {
204e011f	410	bin = 6;
c2140715	411	}
	412
	413	hard = kFALSE;
	414
	415	Float_t r = gRandom->Rndm();
	416
	417	if (r < p) hard = kTRUE;
	418	}
	419
	420
5b3a5a5d	421	Float_t AliFastGlauber::GetRandomImpactParameter(Float_t bmin, Float_t bmax)
	422	{
	423	//
	424	// Gives back a random impact parameter in the range bmin .. bmax
	425	//
	426
	427	Float_t b = -1.;
	428	while(b < bmin \|\| b > bmax)
	429	b = fWSgeo->GetRandom();
	430	return b;
	431	}
	432
	433	Double_t AliFastGlauber::CrossSection(Double_t b1, Double_t b2)
	434	{
	435	//
	436	// Return cross-section integrated from b1 to b2
	437	//
	438
	439	return fWSgeo->Integral(b1, b2)/100.;
	440	}
	441
	442	Double_t AliFastGlauber::FractionOfHardCrossSection(Double_t b1, Double_t b2)
	443	{
	444	//
	445	// Return raction of hard cross-section integrated from b1 to b2
	446	//
	447
	448	return fWSbinary->Integral(b1, b2)/fWSbinary->Integral(0., 100.);
	449	}
	450
	451
	452	Double_t AliFastGlauber::Binaries(Double_t b)
	453	{
	454	//
	455	// Return number of binary collisions normalized to 1 at b=0
	456	//
	457
270181a5	458	return fWSN->Eval(b)/fWSN->Eval(0.);
5b3a5a5d	459	}