[u/mrichter/AliRoot.git] / ANALYSIS / TenderSupplies / AliTrackFixTenderSupply.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.                  *
 **************************************************************************/


///////////////////////////////////////////////////////////////////////////////
//                                                                           //
// Redo primary vertex on the fly, using the diamond constraint              //
//                                                                           //
///////////////////////////////////////////////////////////////////////////////

#include <TSystem.h>
#include "AliESDEvent.h"
#include "AliTender.h"
#include "AliVParticle.h"
#include "AliLog.h"
#include "AliOADBContainer.h"
#include "AliAnalysisManager.h"
#include "AliTrackFixTenderSupply.h"
#include "AliOADBTrackFix.h"

ClassImp(AliTrackFixTenderSupply)

AliTrackFixTenderSupply::AliTrackFixTenderSupply() :
fDebug(0),
  fBz(0),
  fParams(0),
  fOADBObjPath("$OADB/PWGPP/data/CorrPTInv.root"),
  fOADBObjName("CorrPTInv"),
  fOADBCont(0)
{
  // default ctor
}

//_____________________________________________________
AliTrackFixTenderSupply::AliTrackFixTenderSupply(const char *name, const AliTender *tender) :
  AliTenderSupply(name,tender),
  fDebug(0),
  fBz(0),
  fParams(0),
  fOADBObjPath("$OADB/PWGPP/data/CorrPTInv.root"),
  fOADBObjName("CorrPTInv"),
  fOADBCont(0)
{
  // named ctor
  //
}

//_____________________________________________________
AliTrackFixTenderSupply::~AliTrackFixTenderSupply()
{
  // d-tor
  delete fOADBCont;
}


//_____________________________________________________
void AliTrackFixTenderSupply::ProcessEvent()
{
  //
  // Fix track kinematics
  //
  AliESDEvent *event=fTender->GetEvent();
  if (!event) return;
  //
  if (fTender->RunChanged() && !GetRunCorrections(fTender->GetRun())) return;
  //
  int nTracks = event->GetNumberOfTracks();
  fBz = event->GetMagneticField();
  if (TMath::Abs(fBz) < kAlmost0Field) return;
  //
  const AliESDVertex *vtx = 0, *vtxTPC = 0;
  //
  vtx = event->GetPrimaryVertexTracks(); // vertex to be used for update via RelateToVertex
  if (!vtx || vtx->GetStatus()<1) {
    vtx = event->GetPrimaryVertexSPD();
    if (vtx && vtx->GetStatus()<1) vtx = 0;
  }
  vtxTPC = event->GetPrimaryVertexTPC(); // vertex to be used for update via RelateToVertexTPC
  if (vtxTPC && vtxTPC->GetStatus()<1) vtxTPC = 0;
  //  
  AliExternalTrackParam* extPar = 0;
  double xOrig = 0;
  double xyzTPCInner[3] = {0,0,0};
  for (int itr=0;itr<nTracks;itr++) {
    //
    AliESDtrack* trc = event->GetTrack(itr);
    if (!trc->IsOn(AliESDtrack::kTPCin)) continue;
    //
    double sideAfraction = GetSideAFraction(trc);
    // correct the main parameterization
    int cormode = trc->IsOn(AliESDtrack::kITSin) ? AliOADBTrackFix::kCorModeGlob : AliOADBTrackFix::kCorModeTPCInner;
    xOrig = trc->GetX();
    double xIniCor = fParams->GetXIniPtInvCorr(cormode);
    const AliExternalTrackParam* parInner = trc->GetInnerParam();
    if (!parInner) {
      AliError("Failed to extract inner param");
      continue;
    }
    parInner->GetXYZ(xyzTPCInner);
    double phi = TMath::ATan2(xyzTPCInner[1],xyzTPCInner[0]);
    if (phi<0) phi += 2*TMath::Pi();
    //
    if (fDebug>1) {
      AliInfo(Form("Tr:%4d kITSin:%d Phi=%+5.2f at X=%+7.2f | SideA fraction: %.3f",itr,trc->IsOn(AliESDtrack::kITSin),phi,parInner->GetX(),sideAfraction));
      AliInfo(Form("Main Param before corr. in mode %s, xIni:%.1f",cormode== AliOADBTrackFix::kCorModeGlob ?  "Glo":"TPC",xIniCor));
      trc->AliExternalTrackParam::Print();
    }
    //
    if (xIniCor>0) trc->PropagateTo(xIniCor,fBz);
    CorrectTrackPtInv(trc, cormode, sideAfraction, phi);
    if (xIniCor>0) {                             // full update is requested
      if (vtx) trc->RelateToVertex(vtx, fBz, kVeryBig); // redo DCA if vtx is available
      else     trc->PropagateTo(xOrig, fBz);            // otherwise bring to original point
    }
    // 
    if (fDebug>1) {
      AliInfo("Main Param after corr.");
      trc->AliExternalTrackParam::Print();
    }
    // correct TPCinner param
    if ( (extPar=(AliExternalTrackParam*)trc->GetTPCInnerParam()) ) {
      cormode = AliOADBTrackFix::kCorModeTPCInner;
      xOrig = extPar->GetX();
      xIniCor = fParams->GetXIniPtInvCorr(cormode);
      if (fDebug>1) {
	AliInfo(Form("TPCinner Param before corr. in mode %s, xIni:%.1f",cormode== AliOADBTrackFix::kCorModeGlob ?  "Glo":"TPC",xIniCor));
	extPar->AliExternalTrackParam::Print();
      }
      //
      if (xIniCor>0) extPar->PropagateTo(xIniCor,fBz);
      CorrectTrackPtInv(extPar,cormode,sideAfraction, phi);
      if (xIniCor>0) {                              // full update is requested
	if (vtxTPC) trc->RelateToVertexTPC(vtxTPC, fBz, kVeryBig);  // redo DCA if vtx is available
	else        extPar->PropagateTo(xOrig, fBz);                // otherwise bring to original point
      }
      //
      if (fDebug>1) {
	AliInfo("TPCinner Param after corr.");
	extPar->AliExternalTrackParam::Print();
      }      
    }
    //
  }
  //
}

//_____________________________________________________
void AliTrackFixTenderSupply::CorrectTrackPtInv(AliExternalTrackParam* trc, Int_t mode, double sideAfraction, double phi) const
{
  // fix track kinematics
  if (!trc) return;
  double *param = (double*)trc->GetParameter();
  param[4] += fParams->GetPtInvCorr(mode,sideAfraction,phi);
  //
}

//_____________________________________________________
Bool_t AliTrackFixTenderSupply::LoadOADBObjects()
{
  // Load OADB parameters
  TString fileName = fOADBObjPath;
  if (fileName.BeginsWith("$OADB")) fileName.ReplaceAll("$OADB",Form("%s/",AliAnalysisManager::GetOADBPath()));
  gSystem->ExpandPathName(fileName);
  AliInfo(Form("Loading correction parameters %s from %s",fOADBObjName.Data(),fileName.Data()));
  //
  fOADBCont = new AliOADBContainer("OADB");
  if (fOADBCont->InitFromFile(fileName.Data(),fOADBObjName.Data())) {
    AliError("Failed to load OADB Container");
    delete fOADBCont;
    fOADBCont = 0;
    return kFALSE;
  }
  //
  return kTRUE;
}

//_____________________________________________________
Bool_t AliTrackFixTenderSupply::GetRunCorrections(int run)
{
  // extract corrections for given run
  fParams = 0;
  if (!fOADBCont) if (!LoadOADBObjects()) return kFALSE;
  fParams = dynamic_cast<AliOADBTrackFix*>(fOADBCont->GetObject(run,"default"));
  if (!fParams) {AliError(Form("No correction parameters for found for run %d",run)); return kFALSE;}
  AliInfo(Form("Loaded correction parameters for run %d",run));
  //
  return kTRUE;
}

//_____________________________________________________
Double_t AliTrackFixTenderSupply::GetSideAFraction(const AliESDtrack* track) const
{
  // decide A-side fraction of trajectory length in TPC 
  // for the moment just a placeholder...
  //
  const AliExternalTrackParam *trIn = track->GetInnerParam();
  if (!trIn) {AliError("Failed to onbtain InnerParam"); return 0.5;}
  //
  // easy cases:
  double sideAfrac = 0.5;
  if      (trIn->GetZ()>0) { sideAfrac = 1.; if (trIn->GetTgl()>-kAlmost0) return sideAfrac;}
  else if (trIn->GetZ()<0) { sideAfrac = 0.; if (trIn->GetTgl()< kAlmost0) return sideAfrac;}
  //
  // track may cross the membrane
  // convert to usual helix param: 
  // x(t)=(dca+R)*cos(phi0) -R*cos(t+phi0);
  // y(t)=(dca+R)*sin(phi0) -R*sin(t+phi0);
  // z(t)=z0 - R*t*tgl
  //
  int sqb = fBz<0 ? -trIn->Charge() : trIn->Charge();
  double radq = TMath::Abs(trIn->GetC(fBz));
  radq = radq>kAlmost0 ? 1./radq : 1e4; // track radius
  if (sqb<0) radq = -radq;
  double cstCphi0 =  trIn->GetSnp(); // tC is current t
  double sntCphi0 = -TMath::Sqrt((1.-cstCphi0)*(1+cstCphi0));
  double xc0 = trIn->GetX() + radq*cstCphi0; // circle center
  double yc0 = trIn->GetY() + radq*sntCphi0;
  double phi0 = TMath::ATan2( yc0, xc0);
  if (sqb<0) phi0 += TMath::Pi();
  if      (phi0 > TMath::Pi()) phi0 -= 2.*TMath::Pi();
  else if (phi0 <-TMath::Pi()) phi0 += 2.*TMath::Pi();
  //
  double csphi0 = TMath::Cos(phi0);
  double snphi0 = TMath::Sin(phi0);
  double dca    = xc0*csphi0 + yc0*snphi0 - radq;
  double tC     = TMath::ATan2(sntCphi0,cstCphi0) - phi0;
  double tglR   = radq*trIn->GetTgl();
  double z0     = trIn->GetZ() + tglR*tC;
  Double_t tCross = z0/tglR;  // Z=0 is crossed at this t
  // t is changed withing tCross:2pi range for the track moving forward
  if (tCross<tC || tCross>TMath::Pi()) return sideAfrac;  // on the way forward does not cross the membrane
  //
  // find max t reached by the track in the TPC
  const double kROutTPC2 = 250.*250.;
  // find t at which the outer radius is crossed
  // r^2 = (dca+R)^2 + R^2 - 2R(R+dca)*cos(t)
  double dcaR = dca+radq;
  double rmax2 = dcaR*dcaR + radq*radq + 2*radq*dcaR; // max rad at t=pi
  double tmax = TMath::Pi();
  if (rmax2>kROutTPC2) { // traverses full TPC
    double ct = 0.5*(dcaR/radq + radq/dcaR - kROutTPC2/radq/dcaR);    
    if (TMath::Abs(ct)<1-kAlmost0) tmax = TMath::ACos(ct);
  }
  if (tmax<tCross) return sideAfrac;  // does not cross z=0
  sideAfrac = sideAfrac>0.5 ? (tCross-tC)/(tmax-tC) : 1.-(tCross-tC)/(tmax-tC);
  return sideAfrac;
}
Commit	Line	Data
4d44dfb6	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
	16
	17	///////////////////////////////////////////////////////////////////////////////
	18	// //
	19	// Redo primary vertex on the fly, using the diamond constraint //
	20	// //
	21	///////////////////////////////////////////////////////////////////////////////
	22
	23	#include <TSystem.h>
	24	#include "AliESDEvent.h"
	25	#include "AliTender.h"
	26	#include "AliVParticle.h"
	27	#include "AliLog.h"
	28	#include "AliOADBContainer.h"
	29	#include "AliAnalysisManager.h"
	30	#include "AliTrackFixTenderSupply.h"
	31	#include "AliOADBTrackFix.h"
	32
	33	ClassImp(AliTrackFixTenderSupply)
	34
	35	AliTrackFixTenderSupply::AliTrackFixTenderSupply() :
1112c329	36	fDebug(0),
1112c329	37	fBz(0),
4d44dfb6	38	fParams(0),
1112c329	39	fOADBObjPath("$OADB/PWGPP/data/CorrPTInv.root"),
4d44dfb6	40	fOADBObjName("CorrPTInv"),
	41	fOADBCont(0)
	42	{
	43	// default ctor
	44	}
	45
	46	//_____________________________________________________
	47	AliTrackFixTenderSupply::AliTrackFixTenderSupply(const char name, const AliTender tender) :
	48	AliTenderSupply(name,tender),
1112c329	49	fDebug(0),
4d44dfb6	50	fBz(0),
4d44dfb6	51	fParams(0),
1112c329	52	fOADBObjPath("$OADB/PWGPP/data/CorrPTInv.root"),
4d44dfb6	53	fOADBObjName("CorrPTInv"),
	54	fOADBCont(0)
	55	{
	56	// named ctor
	57	//
	58	}
	59
	60	//_____________________________________________________
	61	AliTrackFixTenderSupply::~AliTrackFixTenderSupply()
	62	{
	63	// d-tor
	64	delete fOADBCont;
	65	}
	66
	67
	68	//_____________________________________________________
	69	void AliTrackFixTenderSupply::ProcessEvent()
	70	{
	71	//
	72	// Fix track kinematics
	73	//
	74	AliESDEvent *event=fTender->GetEvent();
	75	if (!event) return;
	76	//
	77	if (fTender->RunChanged() && !GetRunCorrections(fTender->GetRun())) return;
	78	//
	79	int nTracks = event->GetNumberOfTracks();
	80	fBz = event->GetMagneticField();
	81	if (TMath::Abs(fBz) < kAlmost0Field) return;
	82	//
	83	const AliESDVertex vtx = 0, vtxTPC = 0;
	84	//
	85	vtx = event->GetPrimaryVertexTracks(); // vertex to be used for update via RelateToVertex
	86	if (!vtx \|\| vtx->GetStatus()<1) {
	87	vtx = event->GetPrimaryVertexSPD();
	88	if (vtx && vtx->GetStatus()<1) vtx = 0;
	89	}
	90	vtxTPC = event->GetPrimaryVertexTPC(); // vertex to be used for update via RelateToVertexTPC
1112c329	91	if (vtxTPC && vtxTPC->GetStatus()<1) vtxTPC = 0;
4d44dfb6	92	//
	93	AliExternalTrackParam* extPar = 0;
	94	double xOrig = 0;
51732659	95	double xyzTPCInner[3] = {0,0,0};
4d44dfb6	96	for (int itr=0;itr<nTracks;itr++) {
	97	//
	98	AliESDtrack* trc = event->GetTrack(itr);
	99	if (!trc->IsOn(AliESDtrack::kTPCin)) continue;
	100	//
	101	double sideAfraction = GetSideAFraction(trc);
	102	// correct the main parameterization
	103	int cormode = trc->IsOn(AliESDtrack::kITSin) ? AliOADBTrackFix::kCorModeGlob : AliOADBTrackFix::kCorModeTPCInner;
	104	xOrig = trc->GetX();
	105	double xIniCor = fParams->GetXIniPtInvCorr(cormode);
	106	const AliExternalTrackParam* parInner = trc->GetInnerParam();
	107	if (!parInner) {
	108	AliError("Failed to extract inner param");
	109	continue;
	110	}
51732659	111	parInner->GetXYZ(xyzTPCInner);
e505d150	112	double phi = TMath::ATan2(xyzTPCInner[1],xyzTPCInner[0]);
e505d150	113	if (phi<0) phi += 2*TMath::Pi();
4d44dfb6	114	//
1112c329	115	if (fDebug>1) {
	116	AliInfo(Form("Tr:%4d kITSin:%d Phi=%+5.2f at X=%+7.2f \| SideA fraction: %.3f",itr,trc->IsOn(AliESDtrack::kITSin),phi,parInner->GetX(),sideAfraction));
	117	AliInfo(Form("Main Param before corr. in mode %s, xIni:%.1f",cormode== AliOADBTrackFix::kCorModeGlob ? "Glo":"TPC",xIniCor));
	118	trc->AliExternalTrackParam::Print();
	119	}
	120	//
4d44dfb6	121	if (xIniCor>0) trc->PropagateTo(xIniCor,fBz);
	122	CorrectTrackPtInv(trc, cormode, sideAfraction, phi);
	123	if (xIniCor>0) { // full update is requested
	124	if (vtx) trc->RelateToVertex(vtx, fBz, kVeryBig); // redo DCA if vtx is available
	125	else trc->PropagateTo(xOrig, fBz); // otherwise bring to original point
	126	}
	127	//
1112c329	128	if (fDebug>1) {
	129	AliInfo("Main Param after corr.");
	130	trc->AliExternalTrackParam::Print();
	131	}
4d44dfb6	132	// correct TPCinner param
	133	if ( (extPar=(AliExternalTrackParam*)trc->GetTPCInnerParam()) ) {
	134	cormode = AliOADBTrackFix::kCorModeTPCInner;
	135	xOrig = extPar->GetX();
	136	xIniCor = fParams->GetXIniPtInvCorr(cormode);
1112c329	137	if (fDebug>1) {
	138	AliInfo(Form("TPCinner Param before corr. in mode %s, xIni:%.1f",cormode== AliOADBTrackFix::kCorModeGlob ? "Glo":"TPC",xIniCor));
	139	extPar->AliExternalTrackParam::Print();
	140	}
	141	//
4d44dfb6	142	if (xIniCor>0) extPar->PropagateTo(xIniCor,fBz);
	143	CorrectTrackPtInv(extPar,cormode,sideAfraction, phi);
	144	if (xIniCor>0) { // full update is requested
	145	if (vtxTPC) trc->RelateToVertexTPC(vtxTPC, fBz, kVeryBig); // redo DCA if vtx is available
	146	else extPar->PropagateTo(xOrig, fBz); // otherwise bring to original point
	147	}
1112c329	148	//
	149	if (fDebug>1) {
	150	AliInfo("TPCinner Param after corr.");
	151	extPar->AliExternalTrackParam::Print();
	152	}
4d44dfb6	153	}
	154	//
	155	}
	156	//
	157	}
	158
	159	//_____________________________________________________
	160	void AliTrackFixTenderSupply::CorrectTrackPtInv(AliExternalTrackParam* trc, Int_t mode, double sideAfraction, double phi) const
	161	{
	162	// fix track kinematics
	163	if (!trc) return;
	164	double param = (double)trc->GetParameter();
	165	param[4] += fParams->GetPtInvCorr(mode,sideAfraction,phi);
	166	//
	167	}
	168
	169	//_____________________________________________________
	170	Bool_t AliTrackFixTenderSupply::LoadOADBObjects()
	171	{
	172	// Load OADB parameters
	173	TString fileName = fOADBObjPath;
	174	if (fileName.BeginsWith("$OADB")) fileName.ReplaceAll("$OADB",Form("%s/",AliAnalysisManager::GetOADBPath()));
	175	gSystem->ExpandPathName(fileName);
	176	AliInfo(Form("Loading correction parameters %s from %s",fOADBObjName.Data(),fileName.Data()));
	177	//
	178	fOADBCont = new AliOADBContainer("OADB");
	179	if (fOADBCont->InitFromFile(fileName.Data(),fOADBObjName.Data())) {
	180	AliError("Failed to load OADB Container");
	181	delete fOADBCont;
	182	fOADBCont = 0;
	183	return kFALSE;
	184	}
	185	//
	186	return kTRUE;
	187	}
	188
	189	//_____________________________________________________
	190	Bool_t AliTrackFixTenderSupply::GetRunCorrections(int run)
	191	{
	192	// extract corrections for given run
	193	fParams = 0;
	194	if (!fOADBCont) if (!LoadOADBObjects()) return kFALSE;
	195	fParams = dynamic_cast<AliOADBTrackFix*>(fOADBCont->GetObject(run,"default"));
	196	if (!fParams) {AliError(Form("No correction parameters for found for run %d",run)); return kFALSE;}
	197	AliInfo(Form("Loaded correction parameters for run %d",run));
	198	//
	199	return kTRUE;
	200	}
	201
	202	//_____________________________________________________
	203	Double_t AliTrackFixTenderSupply::GetSideAFraction(const AliESDtrack* track) const
	204	{
	205	// decide A-side fraction of trajectory length in TPC
	206	// for the moment just a placeholder...
	207	//
	208	const AliExternalTrackParam *trIn = track->GetInnerParam();
	209	if (!trIn) {AliError("Failed to onbtain InnerParam"); return 0.5;}
	210	//
	211	// easy cases:
	212	double sideAfrac = 0.5;
	213	if (trIn->GetZ()>0) { sideAfrac = 1.; if (trIn->GetTgl()>-kAlmost0) return sideAfrac;}
	214	else if (trIn->GetZ()<0) { sideAfrac = 0.; if (trIn->GetTgl()< kAlmost0) return sideAfrac;}
	215	//
	216	// track may cross the membrane
217	// convert to usual helix param:
218	// x(t)=(dca+R)cos(phi0) -Rcos(t+phi0);
219	// y(t)=(dca+R)sin(phi0) -Rsin(t+phi0);
220	// z(t)=z0 - Rttgl
221	//
222	int sqb = fBz<0 ? -trIn->Charge() : trIn->Charge();
223	double radq = TMath::Abs(trIn->GetC(fBz));
224	radq = radq>kAlmost0 ? 1./radq : 1e4; // track radius
225	if (sqb<0) radq = -radq;
226	double cstCphi0 = trIn->GetSnp(); // tC is current t
227	double sntCphi0 = -TMath::Sqrt((1.-cstCphi0)*(1+cstCphi0));
228	double xc0 = trIn->GetX() + radq*cstCphi0; // circle center
229	double yc0 = trIn->GetY() + radq*sntCphi0;
230	double phi0 = TMath::ATan2( yc0, xc0);
231	if (sqb<0) phi0 += TMath::Pi();
232	if (phi0 > TMath::Pi()) phi0 -= 2.*TMath::Pi();
233	else if (phi0 <-TMath::Pi()) phi0 += 2.*TMath::Pi();
234	//
235	double csphi0 = TMath::Cos(phi0);
236	double snphi0 = TMath::Sin(phi0);
237	double dca = xc0csphi0 + yc0snphi0 - radq;
238	double tC = TMath::ATan2(sntCphi0,cstCphi0) - phi0;
239	double tglR = radq*trIn->GetTgl();
240	double z0 = trIn->GetZ() + tglR*tC;
241	Double_t tCross = z0/tglR; // Z=0 is crossed at this t
242	// t is changed withing tCross:2pi range for the track moving forward
243	if (tCross<tC \|\| tCross>TMath::Pi()) return sideAfrac; // on the way forward does not cross the membrane
244	//
245	// find max t reached by the track in the TPC
246	const double kROutTPC2 = 250.*250.;
247	// find t at which the outer radius is crossed
248	// r^2 = (dca+R)^2 + R^2 - 2R(R+dca)*cos(t)
249	double dcaR = dca+radq;
250	double rmax2 = dcaRdcaR + radqradq + 2radqdcaR; // max rad at t=pi
251	double tmax = TMath::Pi();
252	if (rmax2>kROutTPC2) { // traverses full TPC
253	double ct = 0.5*(dcaR/radq + radq/dcaR - kROutTPC2/radq/dcaR);
254	if (TMath::Abs(ct)<1-kAlmost0) tmax = TMath::ACos(ct);
255	}
256	if (tmax<tCross) return sideAfrac; // does not cross z=0
257	sideAfrac = sideAfrac>0.5 ? (tCross-tC)/(tmax-tC) : 1.-(tCross-tC)/(tmax-tC);
258	return sideAfrac;
259	}