[u/mrichter/AliRoot.git] / STEER / AliLego.cxx

//////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////
//                            
//  Utility class to evaluate the material budget from
//  a given radius to the surface of an arbitrary cylinder
//  along radial directions from the centre:
// 
//   - radiation length
//   - Interaction length
//   - g/cm2
// 
//  Geantinos are shot in the bins in the fNtheta bins in theta
//  and fNphi bins in phi with specified rectangular limits.
//  The statistics are accumulated per
//    fRadMin < r < fRadMax    and  <0 < z < fZMax
//
//  To activate this option, you can do:
//      Root > gAlice.RunLego();
//  or  Root > .x menu.C  then select menu item "RunLego"
//  Note that when calling gAlice->RunLego, an optional list
//  of arguments may be specified.
//
//Begin_Html
/*
<img src="picts/alilego.gif">
*/
//End_Html
//
//////////////////////////////////////////////////////////////

#include "TMath.h"
#include "AliLego.h"
#include "AliRun.h"
#include "AliConst.h"

ClassImp(AliLego)


//___________________________________________
AliLego::AliLego()
{
   fHistRadl = 0;
   fHistAbso = 0;
   fHistGcm2 = 0;
   fHistReta = 0;
}

//___________________________________________
AliLego::AliLego(const char *name, const char *title) 
        : TNamed(name,title)
{
   fHistRadl = 0;
   fHistAbso = 0;
   fHistGcm2 = 0;
   fHistReta = 0;
}

//___________________________________________
AliLego::~AliLego()
{
   delete fHistRadl;
   delete fHistAbso;
   delete fHistGcm2;
   delete fHistReta;
}

//___________________________________________
void AliLego::GenerateKinematics()
{
// Create a geantino with kinematics corresponding to the current
// bins in theta and phi.
   
  //
  // Rootinos are 0
   const Int_t mpart = 0;
   Float_t orig[3], pmom[3];
   Float_t t, cost, sint, cosp, sinp;
   
// --- Set to 0 radiation length, absorption length and g/cm2 ---
   fTotRadl = 0;
   fTotAbso = 0;
   fTotGcm2 = 0;

   fCurTheta = (fThetaMin+(fThetaBin-0.5)*(fThetaMax-fThetaMin)/fNtheta)*kDegrad;
   fCurPhi   = (fPhiMin+(fPhiBin-0.5)*(fPhiMax-fPhiMin)/fNphi)*kDegrad;
   cost      = TMath::Cos(fCurTheta);
   sint      = TMath::Sin(fCurTheta);
   cosp      = TMath::Cos(fCurPhi);
   sinp      = TMath::Sin(fCurPhi);

   pmom[0] = cosp*sint;
   pmom[1] = sinp*sint;
   pmom[2] = cost;

// --- Where to start
   orig[0] = orig[1] = orig[2] = 0;
   Float_t dalicz = 3000;
   if (fRadMin > 0) {
      t = PropagateCylinder(orig,pmom,fRadMin,dalicz);
      orig[0] = pmom[0]*t;
      orig[1] = pmom[1]*t;
      orig[2] = pmom[2]*t;
      if (TMath::Abs(orig[2]) > fZMax) return;
   }

// --- We do start here
   Float_t polar[3]={0.,0.,0.};
   Int_t ntr;
   gAlice->SetTrack(1, 0, mpart, pmom, orig, polar, 0, "LEGO ray", ntr);
}

//___________________________________________
void AliLego::Init(Int_t ntheta,Float_t themin,Float_t themax,
          Int_t nphi,Float_t phimin,Float_t phimax,Float_t rmin,Float_t rmax,
		  Float_t zmax)
{
// specify the angular limits and the size of the rectangular box
   fNtheta   = ntheta;
   fThetaMin = themin;
   fThetaMax = themax;
   fNphi     = nphi;
   fPhiMin   = phimin;
   fPhiMax   = phimax;
   fRadMin   = rmin;
   fRadMax   = rmax;
   fZMax     = zmax;
   Float_t etamin = -TMath::Log(TMath::Tan(TMath::Min((Double_t)fThetaMax*kDegrad/2,TMath::Pi()/2-1.e-10)));
   Float_t etamax = -TMath::Log(TMath::Tan(TMath::Max((Double_t)fThetaMin*kDegrad/2,              1.e-10)));

   fHistRadl = new TH2F("hradl","Radiation length map",    nphi,phimin,phimax,ntheta,themin,themax);
   fHistAbso = new TH2F("habso","Interaction length map",  nphi,phimin,phimax,ntheta,themin,themax);
   fHistGcm2 = new TH2F("hgcm2","g/cm2 length map",        nphi,phimin,phimax,ntheta,themin,themax);
   fHistReta = new TH2F("hetar","Radiation length vs. eta",nphi,phimin,phimax,ntheta,etamin,etamax);

}

//___________________________________________
Float_t AliLego::PropagateCylinder(Float_t *x, Float_t *v, Float_t r, Float_t z)
{
// Propagate to cylinder from inside

   Double_t hnorm, sz, t, t1, t2, t3, sr;
   Double_t d[3];
   const Float_t kSmall  = 1e-8;
   const Float_t kSmall2 = kSmall*kSmall;

// ---> Find intesection with Z planes
   d[0]  = v[0];
   d[1]  = v[1];
   d[2]  = v[2];
   hnorm = TMath::Sqrt(1/(d[0]*d[0]+d[1]*d[1]+d[2]*d[2]));
   d[0] *= hnorm;
   d[1] *= hnorm;
   d[2] *= hnorm;
   if (d[2] > kSmall)       sz = (z-x[2])/d[2];
   else if (d[2] < -kSmall) sz = -(z+x[2])/d[2];
   else                     sz = 1.e10;  // ---> Direction parallel to X-Y, no intersection

// ---> Intersection with cylinders
//      Intersection point (x,y,z)
//      (x,y,z) is on track :    x=X(1)+t*D(1)
//                               y=X(2)+t*D(2)
//                               z=X(3)+t*D(3)
//      (x,y,z) is on cylinder : x**2 + y**2 = R**2
//
//      (D(1)**2+D(2)**2)*t**2
//      +2.*(X(1)*D(1)+X(2)*D(2))*t
//      +X(1)**2+X(2)**2-R**2=0
// ---> Solve second degree equation
   t1 = d[0]*d[0] + d[1]*d[1];
   if (t1 <= kSmall2) {
      t = sz;  // ---> Track parallel to the z-axis, take distance to planes
   } else {
      t2 = x[0]*d[0] + x[1]*d[1];
      t3 = x[0]*x[0] + x[1]*x[1];
      // ---> It should be positive, but there may be numerical problems
      sr = (t2 +TMath::Sqrt(TMath::Max(t2*t2-(t3-r*r)*t1,0.)))/t1;
      // ---> Find minimum distance between planes and cylinder
      t  = TMath::Min(sz,sr);
   }
   return t;
}

//___________________________________________
void AliLego::Run()
{
   // loop on phi,theta bins
   gMC->InitLego();
   Float_t thed, phid, eta;
   for (fPhiBin=1; fPhiBin<=fNphi; fPhiBin++) {
      printf("AliLego Generating rays in phi bin:%d\n",fPhiBin);
      for (fThetaBin=1; fThetaBin<=fNtheta; fThetaBin++) {
         gMC->Gtrigi();
         gMC->Gtrigc();
         GenerateKinematics();
         gMC->Gtreve_root();

         thed = fCurTheta*kRaddeg;
         phid = fCurPhi*kRaddeg;
	 eta  = -TMath::Log(TMath::Tan(TMath::Max(
                     TMath::Min((Double_t)fCurTheta/2,TMath::Pi()/2-1.e-10),1.e-10)));
         fHistRadl->Fill(phid,thed,fTotRadl);
         fHistAbso->Fill(phid,thed,fTotAbso);
         fHistGcm2->Fill(phid,thed,fTotGcm2);
	 fHistReta->Fill(phid,eta,fTotRadl);
         gAlice->FinishEvent();
      }
   }
   // store histograms in current Root file
   fHistRadl->Write();
   fHistAbso->Write();
   fHistGcm2->Write();
   fHistReta->Write();
}

//___________________________________________
void AliLego::StepManager()
{
// called from AliRun::Stepmanager from gustep.
// Accumulate the 3 parameters step by step
  
   Float_t t, tt;
   Float_t a,z,dens,radl,absl;
   Int_t i;
   Bool_t out;
   
   Float_t step  = gMC->TrackStep();
       
   Float_t vect[3], dir[3];
   TLorentzVector pos, mom;

   gMC->TrackPosition(pos);  
   gMC->TrackMomentum(mom);
   gMC->CurrentMaterial(a,z,dens,radl,absl);
   
   if (z < 1) return;
   
// --- See how long we have to go
   if (TMath::Abs(pos[2]) <= fZMax  && 
       pos[0]*pos[0] +pos[1]*pos[1] <= fRadMax*fRadMax) {

     tt = step;
     out = kFALSE;
   } else {

      for(i=0;i<3;++i) {
	vect[i]=pos[i];
	dir[i]=mom[i];
      }
      t  = PropagateCylinder(vect,dir,fRadMax,fZMax);
      tt = TMath::Min(step,t);
      out = kTRUE;
   }

   fTotAbso += tt/absl;
   fTotRadl += tt/radl;
   fTotGcm2 += tt*dens;

// --- See if we have to stop now
   if(out) gMC->StopEvent();
}
Commit	Line	Data
fe4da5cc	1	//////////////////////////////////////////////////////////////
	2	//////////////////////////////////////////////////////////////
	3	//
	4	// Utility class to evaluate the material budget from
	5	// a given radius to the surface of an arbitrary cylinder
	6	// along radial directions from the centre:
	7	//
	8	// - radiation length
	9	// - Interaction length
	10	// - g/cm2
	11	//
	12	// Geantinos are shot in the bins in the fNtheta bins in theta
	13	// and fNphi bins in phi with specified rectangular limits.
	14	// The statistics are accumulated per
	15	// fRadMin < r < fRadMax and <0 < z < fZMax
	16	//
	17	// To activate this option, you can do:
	18	// Root > gAlice.RunLego();
	19	// or Root > .x menu.C then select menu item "RunLego"
	20	// Note that when calling gAlice->RunLego, an optional list
	21	// of arguments may be specified.
	22	//
	23	//Begin_Html
	24	/*
1439f98e	25	<img src="picts/alilego.gif">
fe4da5cc	26	*/
	27	//End_Html
	28	//
	29	//////////////////////////////////////////////////////////////
	30
	31	#include "TMath.h"
1578254f	32	#include "AliLego.h"
fe4da5cc	33	#include "AliRun.h"
	34	#include "AliConst.h"
	35
	36	ClassImp(AliLego)
	37
	38
	39	//___________________________________________
	40	AliLego::AliLego()
	41	{
	42	fHistRadl = 0;
	43	fHistAbso = 0;
	44	fHistGcm2 = 0;
	45	fHistReta = 0;
	46	}
	47
	48	//___________________________________________
	49	AliLego::AliLego(const char name, const char title)
	50	: TNamed(name,title)
	51	{
	52	fHistRadl = 0;
	53	fHistAbso = 0;
	54	fHistGcm2 = 0;
	55	fHistReta = 0;
	56	}
	57
	58	//___________________________________________
	59	AliLego::~AliLego()
	60	{
	61	delete fHistRadl;
	62	delete fHistAbso;
	63	delete fHistGcm2;
	64	delete fHistReta;
	65	}
	66
	67	//___________________________________________
	68	void AliLego::GenerateKinematics()
	69	{
	70	// Create a geantino with kinematics corresponding to the current
	71	// bins in theta and phi.
	72
1578254f	73	//
	74	// Rootinos are 0
	75	const Int_t mpart = 0;
fe4da5cc	76	Float_t orig[3], pmom[3];
	77	Float_t t, cost, sint, cosp, sinp;
	78
	79	// --- Set to 0 radiation length, absorption length and g/cm2 ---
	80	fTotRadl = 0;
	81	fTotAbso = 0;
	82	fTotGcm2 = 0;
	83
	84	fCurTheta = (fThetaMin+(fThetaBin-0.5)(fThetaMax-fThetaMin)/fNtheta)kDegrad;
	85	fCurPhi = (fPhiMin+(fPhiBin-0.5)(fPhiMax-fPhiMin)/fNphi)kDegrad;
	86	cost = TMath::Cos(fCurTheta);
	87	sint = TMath::Sin(fCurTheta);
	88	cosp = TMath::Cos(fCurPhi);
	89	sinp = TMath::Sin(fCurPhi);
	90
	91	pmom[0] = cosp*sint;
	92	pmom[1] = sinp*sint;
	93	pmom[2] = cost;
	94
	95	// --- Where to start
	96	orig[0] = orig[1] = orig[2] = 0;
	97	Float_t dalicz = 3000;
	98	if (fRadMin > 0) {
	99	t = PropagateCylinder(orig,pmom,fRadMin,dalicz);
	100	orig[0] = pmom[0]*t;
	101	orig[1] = pmom[1]*t;
	102	orig[2] = pmom[2]*t;
	103	if (TMath::Abs(orig[2]) > fZMax) return;
	104	}
	105
	106	// --- We do start here
	107	Float_t polar[3]={0.,0.,0.};
	108	Int_t ntr;
	109	gAlice->SetTrack(1, 0, mpart, pmom, orig, polar, 0, "LEGO ray", ntr);
	110	}
	111
	112	//___________________________________________
	113	void AliLego::Init(Int_t ntheta,Float_t themin,Float_t themax,
	114	Int_t nphi,Float_t phimin,Float_t phimax,Float_t rmin,Float_t rmax,
	115	Float_t zmax)
	116	{
	117	// specify the angular limits and the size of the rectangular box
	118	fNtheta = ntheta;
	119	fThetaMin = themin;
	120	fThetaMax = themax;
	121	fNphi = nphi;
	122	fPhiMin = phimin;
	123	fPhiMax = phimax;
	124	fRadMin = rmin;
	125	fRadMax = rmax;
	126	fZMax = zmax;
	127	Float_t etamin = -TMath::Log(TMath::Tan(TMath::Min((Double_t)fThetaMax*kDegrad/2,TMath::Pi()/2-1.e-10)));
	128	Float_t etamax = -TMath::Log(TMath::Tan(TMath::Max((Double_t)fThetaMin*kDegrad/2, 1.e-10)));
	129
	130	fHistRadl = new TH2F("hradl","Radiation length map", nphi,phimin,phimax,ntheta,themin,themax);
	131	fHistAbso = new TH2F("habso","Interaction length map", nphi,phimin,phimax,ntheta,themin,themax);
	132	fHistGcm2 = new TH2F("hgcm2","g/cm2 length map", nphi,phimin,phimax,ntheta,themin,themax);
	133	fHistReta = new TH2F("hetar","Radiation length vs. eta",nphi,phimin,phimax,ntheta,etamin,etamax);
	134
	135	}
	136
	137	//___________________________________________
	138	Float_t AliLego::PropagateCylinder(Float_t x, Float_t v, Float_t r, Float_t z)
	139	{
140	// Propagate to cylinder from inside
141
142	Double_t hnorm, sz, t, t1, t2, t3, sr;
143	Double_t d[3];
144	const Float_t kSmall = 1e-8;
145	const Float_t kSmall2 = kSmall*kSmall;
146
147	// ---> Find intesection with Z planes
148	d[0] = v[0];
149	d[1] = v[1];
150	d[2] = v[2];
151	hnorm = TMath::Sqrt(1/(d[0]d[0]+d[1]d[1]+d[2]*d[2]));
152	d[0] *= hnorm;
153	d[1] *= hnorm;
154	d[2] *= hnorm;
155	if (d[2] > kSmall) sz = (z-x[2])/d[2];
156	else if (d[2] < -kSmall) sz = -(z+x[2])/d[2];
157	else sz = 1.e10; // ---> Direction parallel to X-Y, no intersection
158
159	// ---> Intersection with cylinders
160	// Intersection point (x,y,z)
161	// (x,y,z) is on track : x=X(1)+t*D(1)
162	// y=X(2)+t*D(2)
163	// z=X(3)+t*D(3)
164	// (x,y,z) is on cylinder : x2 + y2 = R**2
165	//
166	// (D(1)2+D(2)2)t*2
167	// +2.(X(1)D(1)+X(2)D(2))t
168	// +X(1)2+X(2)2-R**2=0
169	// ---> Solve second degree equation
170	t1 = d[0]d[0] + d[1]d[1];
171	if (t1 <= kSmall2) {
172	t = sz; // ---> Track parallel to the z-axis, take distance to planes
173	} else {
174	t2 = x[0]d[0] + x[1]d[1];
175	t3 = x[0]x[0] + x[1]x[1];
176	// ---> It should be positive, but there may be numerical problems
177	sr = (t2 +TMath::Sqrt(TMath::Max(t2t2-(t3-rr)*t1,0.)))/t1;
178	// ---> Find minimum distance between planes and cylinder
179	t = TMath::Min(sz,sr);
180	}
181	return t;
182	}
183
184	//___________________________________________
185	void AliLego::Run()
186	{
187	// loop on phi,theta bins
cfce8870	188	gMC->InitLego();
fe4da5cc	189	Float_t thed, phid, eta;
	190	for (fPhiBin=1; fPhiBin<=fNphi; fPhiBin++) {
	191	printf("AliLego Generating rays in phi bin:%d\n",fPhiBin);
	192	for (fThetaBin=1; fThetaBin<=fNtheta; fThetaBin++) {
cfce8870	193	gMC->Gtrigi();
cfce8870	194	gMC->Gtrigc();
fe4da5cc	195	GenerateKinematics();
cfce8870	196	gMC->Gtreve_root();
fe4da5cc	197
	198	thed = fCurTheta*kRaddeg;
	199	phid = fCurPhi*kRaddeg;
	200	eta = -TMath::Log(TMath::Tan(TMath::Max(
	201	TMath::Min((Double_t)fCurTheta/2,TMath::Pi()/2-1.e-10),1.e-10)));
	202	fHistRadl->Fill(phid,thed,fTotRadl);
	203	fHistAbso->Fill(phid,thed,fTotAbso);
	204	fHistGcm2->Fill(phid,thed,fTotGcm2);
	205	fHistReta->Fill(phid,eta,fTotRadl);
	206	gAlice->FinishEvent();
	207	}
	208	}
	209	// store histograms in current Root file
	210	fHistRadl->Write();
	211	fHistAbso->Write();
	212	fHistGcm2->Write();
	213	fHistReta->Write();
	214	}
	215
	216	//___________________________________________
	217	void AliLego::StepManager()
	218	{
	219	// called from AliRun::Stepmanager from gustep.
	220	// Accumulate the 3 parameters step by step
fe4da5cc	221
	222	Float_t t, tt;
	223	Float_t a,z,dens,radl,absl;
0a6d8768	224	Int_t i;
f12866de	225	Bool_t out;
fe4da5cc	226
cfce8870	227	Float_t step = gMC->TrackStep();
fe4da5cc	228
0a6d8768	229	Float_t vect[3], dir[3];
	230	TLorentzVector pos, mom;
	231
	232	gMC->TrackPosition(pos);
	233	gMC->TrackMomentum(mom);
cfce8870	234	gMC->CurrentMaterial(a,z,dens,radl,absl);
fe4da5cc	235
	236	if (z < 1) return;
	237
f12866de	238	// --- See how long we have to go
	239	if (TMath::Abs(pos[2]) <= fZMax &&
	240	pos[0]pos[0] +pos[1]pos[1] <= fRadMax*fRadMax) {
	241
	242	tt = step;
	243	out = kFALSE;
fe4da5cc	244	} else {
fe4da5cc	245
0a6d8768	246	for(i=0;i<3;++i) {
	247	vect[i]=pos[i];
	248	dir[i]=mom[i];
	249	}
	250	t = PropagateCylinder(vect,dir,fRadMax,fZMax);
fe4da5cc	251	tt = TMath::Min(step,t);
f12866de	252	out = kTRUE;
fe4da5cc	253	}
f12866de	254
	255	fTotAbso += tt/absl;
	256	fTotRadl += tt/radl;
	257	fTotGcm2 += tt*dens;
	258
	259	// --- See if we have to stop now
	260	if(out) gMC->StopEvent();
fe4da5cc	261	}
fe4da5cc	262