No OneTemporary
Actions

Size

53 KB

Subscribers

None

View Options

	diff --git a/UnderlyingEvent/MPIHandler.cc b/UnderlyingEvent/MPIHandler.cc
	--- a/UnderlyingEvent/MPIHandler.cc
	+++ b/UnderlyingEvent/MPIHandler.cc
	@@ -1,781 +1,809 @@
	// -- C++ --
	//
	// MPIHandler.cc is a part of Herwig++ - A multi-purpose Monte Carlo event generator
	// Copyright (C) 2002-2011 The Herwig Collaboration
	//
	// Herwig++ is licenced under version 2 of the GPL, see COPYING for details.
	// Please respect the MCnet academic guidelines, see GUIDELINES for details.
	//
	//
	// This is the implementation of the non-inlined, non-templated member
	// functions of the MPIHandler class.
	//

	#include "MPIHandler.h"

	#include "ThePEG/Handlers/StandardXComb.h"
	#include "ThePEG/Handlers/SubProcessHandler.h"
	#include "ThePEG/Interface/ClassDocumentation.h"
	#include "ThePEG/Interface/Parameter.h"
	#include "ThePEG/Interface/Reference.h"
	#include "ThePEG/Interface/RefVector.h"
	#include "ThePEG/Interface/ParVector.h"
	#include "ThePEG/Interface/Switch.h"
	#include "ThePEG/MatrixElement/MEBase.h"
	#include "ThePEG/Handlers/CascadeHandler.h"
	#include "ThePEG/Cuts/Cuts.h"
	#include "ThePEG/Cuts/SimpleKTCut.h"

	#include "gsl/gsl_sf_bessel.h"

	#include "ThePEG/Persistency/PersistentOStream.h"
	#include "ThePEG/Persistency/PersistentIStream.h"

	using namespace Herwig;

	MPIHandler * MPIHandler::currentHandler_ = 0;

	bool MPIHandler::beamOK() const {
	return (HadronMatcher::Check(*eventHandler()->incoming().first) &&
	HadronMatcher::Check(*eventHandler()->incoming().second) );
	}


	tStdXCombPtr MPIHandler::generate(unsigned int sel) {
	//generate a certain process
	if(sel+1 > processHandlers().size())
	throw Exception() << "MPIHandler::generate called with argument out of range"
	<< Exception::runerror;

	return processHandlers()[sel]->generate();
	}

	IBPtr MPIHandler::clone() const {
	return new_ptr(*this);
	}

	IBPtr MPIHandler::fullclone() const {
	return new_ptr(*this);
	}

	void MPIHandler::finalize() {
	if( beamOK() ){
	statistics();
	}
	}

	void MPIHandler::initialize() {
	currentHandler_ = this;
	useMe();
	theHandler = generator()->currentEventHandler();
	//stop if the EventHandler is not present:
	assert(theHandler);

	//check if MPI is wanted
	if( !beamOK() ){
	throw Exception() << "You have requested multiple parton-parton scattering,\n"
	<< "but the model is not forseen for the beam setup you chose.\n"
	<< "You should therefore disable that by setting XXXGenerator:EventHandler:"
	<< "CascadeHandler:MPIHandler to NULL"
	<< Exception::runerror;
	}

	numSubProcs_ = subProcesses().size();

	if( numSubProcs_ != cuts().size() )
	throw Exception() << "MPIHandler::each SubProcess needs a Cuts Object"
	<< "ReferenceVectors are not equal in size"
	<< Exception::runerror;

	if( additionalMultiplicities_.size()+1 != numSubProcs_ )
	throw Exception() << "MPIHandler: each additional SubProcess needs "
	<< "a multiplicity assigned. This can be done in with "
	<< "insert MPIHandler:additionalMultiplicities 0 1"
	<< Exception::runerror;

	//identicalToUE_ = 0 hard process is identical to ue, -1 no one
	if( identicalToUE_ > (int)numSubProcs_ \|\| identicalToUE_ < -1 )
	throw Exception() << "MPIHandler:identicalToUE has disallowed value"
	<< Exception::runerror;

	// override the cuts for the additional scatters if energyExtrapolation_ is
	// set
	- if (energyExtrapolation_) {
	+ if (energyExtrapolation_ != 0 ) {
	overrideUECuts();
	}

	tcPDPtr gluon=getParticleData(ParticleID::g);
	//determine ptmin
	Ptmin_ = cuts()[0]->minKT(gluon);


	if(identicalToUE_ == -1){
	algorithm_ = 2;
	}else{
	if(identicalToUE_ == 0){
	//Need to work a bit, in case of LesHouches events for QCD2to2
	if( dynamic_ptr_cast<Ptr<StandardEventHandler>::pointer>(eventHandler()) ){
	PtOfQCDProc_ = dynamic_ptr_cast
	<Ptr<StandardEventHandler>::pointer>(eventHandler())->cuts()->minKT(gluon);
	}else{
	if(PtOfQCDProc_ == -1.0*GeV)
	throw Exception() << "MPIHandler: You need to specify the pt cutoff "
	<< "used to in the LesHouches file for QCD2to2 events"
	<< Exception::runerror;
	}
	}else{
	PtOfQCDProc_ = cuts()[identicalToUE_]->minKT(gluon);
	}

	if(PtOfQCDProc_ > 2*Ptmin_)
	algorithm_ = 1;
	else
	algorithm_ = 0;

	if(PtOfQCDProc_ == ZERO)//pure MinBias mode
	algorithm_ = -1;
	}

	//Init all subprocesses
	for(unsigned int i=0; i<numSubProcs_; i++){
	theProcessHandlers.push_back(new_ptr(ProcessHandler()));
	processHandlers().back()->initialize(subProcesses()[i],
	cuts()[i], eventHandler());
	processHandlers().back()->initrun();
	}

	//now calculate the individual Probabilities
	XSVector UEXSecs;
	UEXSecs.push_back(processHandlers()[0]->integratedXSec());
	//save the hard cross section
	hardXSec_ = UEXSecs.front();

	//determine sigma_soft and beta
	if(softInt_){//check that soft ints are requested
	GSLBisection rootFinder;

	if(twoComp_){
	//two component model
	/*
	GSLMultiRoot eqSolver;
	slopeAndTotalXSec eq(this);
	pair<CrossSection, Energy2> res = eqSolver.value(eq, 10millibarn, 0.6GeV2);
	softXSec_ = res.first;
	softMu2_ = res.second;
	*/
	slopeBisection fs(this);
	try{
	softMu2_ = rootFinder.value(fs, 0.3GeV2, 1.GeV2);
	softXSec_ = fs.softXSec();
	}catch(GSLBisection::IntervalError){
	throw Exception() <<
	"\n**********************************************************\n"
	"* Inconsistent MPI parameter choice for this beam energy *\n"
	"**********************************************************\n"
	"MPIHandler parameter choice is unable to reproduce\n"
	"the total cross section. Please check arXiv:0806.2949\n"
	"for the allowed parameter space."
	<< Exception::runerror;
	}

	}else{
	//single component model
	TotalXSecBisection fn(this);
	try{
	softXSec_ = rootFinder.value(fn, 0millibarn, 5000millibarn);
	}catch(GSLBisection::IntervalError){
	throw Exception() <<
	"\n**********************************************************\n"
	"* Inconsistent MPI parameter choice for this beam energy *\n"
	"**********************************************************\n"
	"MPIHandler parameter choice is unable to reproduce\n"
	"the total cross section. Please check arXiv:0806.2949\n"
	"for the allowed parameter space."
	<< Exception::runerror;
	}
	}

	//now get the differential cross section at ptmin
	ProHdlPtr qcd = new_ptr(ProcessHandler());
	Energy eps = 0.1*GeV;
	Energy ptminPlus = Ptmin_ + eps;

	Ptr<SimpleKTCut>::pointer ktCut = new_ptr(SimpleKTCut(ptminPlus));
	ktCut->init();
	ktCut->initrun();

	CutsPtr qcdCut = new_ptr(Cuts(2*ptminPlus));
	qcdCut->add(dynamic_ptr_cast<tOneCutPtr>(ktCut));
	qcdCut->init();
	qcdCut->initrun();

	qcd->initialize(subProcesses()[0], qcdCut, eventHandler());
	qcd->initrun();

	// ds/dp_T^2 = 1/2/p_T ds/dp_T
	DiffXSec hardPlus = (hardXSec_-qcd->integratedXSec())/(2Ptmin_eps);

	betaBisection fn2(softXSec_, hardPlus, Ptmin_);
	try{
	beta_ = rootFinder.value(fn2, -10/GeV2, 2/GeV2);
	}catch(GSLBisection::IntervalError){
	throw Exception() << "MPIHandler: slope of soft pt spectrum couldn't be "
	<< "determined."
	<< Exception::runerror;
	}
	}

	Probs(UEXSecs);
	//MultDistribution("probs.test");

	UEXSecs.clear();
	}

	void MPIHandler::MultDistribution(string filename) const {
	ofstream file;
	double p(0.0), pold(0.0);
	file.open(filename.c_str());
	//theMultiplicities
	Selector<MPair>::const_iterator it = theMultiplicities.begin();

	while(it != theMultiplicities.end()){
	p = it->first;
	file << it->second.first << " " << it->second.second
	<< " " << p-pold << '\n';
	it++;
	pold = p;
	}

	file << "sum of all probabilities: " << theMultiplicities.sum()
	<< endl;

	file.close();
	}

	void MPIHandler::statistics() const {
	ostream & file = generator()->misc();

	string line = "======================================="
	"=======================================\n";

	for(unsigned int i=0; i<cuts().size(); i++){
	Stat tot;
	if(i == 0)
	file << "Statistics for the UE process: \n";
	else
	file << "Statistics for additional hard Process " << i << ": \n";

	processHandlers()[i]->statistics(file, tot);
	file << "\n";
	}

	if(softInt_){
	file << line
	<< "Eikonalized and soft cross sections:\n\n"
	<< "Model parameters: "
	<< "ptmin: " << Ptmin_/GeV << " GeV"
	<< ", mu2: " << invRadius_/sqr(1.*GeV) << " GeV2\n"
	<< " "
	<< "DL mode: " << DLmode_
	<< ", CMenergy: " << generator()->maximumCMEnergy()/GeV
	<< " GeV" << '\n'
	<< "hard inclusive cross section (mb): "
	<< hardXSec_/millibarn << '\n'
	<< "soft inclusive cross section (mb): "
	<< softXSec_/millibarn << '\n'
	<< "total cross section (mb): "
	<< totalXSecExp()/millibarn << '\n'
	<< "inelastic cross section (mb): "
	<< inelXSec_/millibarn << '\n'
	<< "soft inv radius (GeV2): "
	<< softMu2_/GeV2 << '\n'
	<< "slope of soft pt spectrum (1/GeV2): "
	<< beta_sqr(1.GeV) << '\n'
	<< "Average hard multiplicity: "
	<< avgNhard_ << '\n'
	<< "Average soft multiplicity: "
	<< avgNsoft_ << '\n' << line << endl;
	}else{
	file << line
	<< "Eikonalized and soft cross sections:\n\n"
	<< "Model parameters: "
	<< "ptmin: " << Ptmin_/GeV << " GeV"
	<< ", mu2: " << invRadius_/sqr(1.*GeV) << " GeV2\n"
	<< " "
	<< ", CMenergy: " << generator()->maximumCMEnergy()/GeV
	<< " GeV" << '\n'
	<< "hard inclusive cross section (mb): "
	<< hardXSec_/millibarn << '\n'
	<< "Average hard multiplicity: "
	<< avgNhard_ << '\n' << line << endl;
	}
	}

	unsigned int MPIHandler::multiplicity(unsigned int sel){
	if(sel==0){//draw from the pretabulated distribution
	MPair m = theMultiplicities.select(UseRandom::rnd());
	softMult_ = m.second;
	return m.first;
	} else{ //fixed multiplicities for the additional hard scatters
	if(additionalMultiplicities_.size() < sel)
	throw Exception() << "MPIHandler::multiplicity: process index "
	<< "is out of range"
	<< Exception::runerror;

	return additionalMultiplicities_[sel-1];
	}
	}


	void MPIHandler::Probs(XSVector UEXSecs) {
	GSLIntegrator integrator;
	unsigned int iH(1), iS(0);
	double P(0.0);
	double P0(0.0);//the probability for i hard and zero soft scatters
	Length bmax(500.0*sqrt(millibarn));
	//only one UE process will be drawn from a probability distribution,
	//so check that.
	assert(UEXSecs.size() == 1);

	for ( XSVector::const_iterator it = UEXSecs.begin();
	it != UEXSecs.end(); ++it ) {

	iH = 0;

	//get the inel xsec
	Eikonalization inelint(this, -1, *it, softXSec_, softMu2_);
	inelXSec_ = integrator.value(inelint, ZERO, bmax);

	avgNhard_ = 0.0;
	avgNsoft_ = 0.0;
	bmax = 10.0*sqrt(millibarn);
	do{//loop over hard ints
	if(Algorithm()>-1 && iH==0){
	iH++;
	continue;
	}
	iS = 0;
	do{//loop over soft ints
	if( ( Algorithm() == -1 && iS==0 && iH==0 ) ){
	iS++;
	continue;
	}

	Eikonalization integrand(this, iH100+iS, it, softXSec_, softMu2_);

	if(Algorithm() > 0){
	P = integrator.value(integrand, ZERO, bmax) / *it;
	}else{
	P = integrator.value(integrand, ZERO, bmax) / inelXSec_;
	}
	//store the probability
	if(Algorithm()>-1){
	theMultiplicities.insert(P, make_pair(iH-1, iS));
	avgNhard_ += P*(iH-1);
	}else{
	theMultiplicities.insert(P, make_pair(iH, iS));
	avgNhard_ += P*(iH);
	}
	avgNsoft_ += P*iS;
	if(iS==0)
	P0 = P;

	iS++;
	} while ( (iS < maxScatters_) && (iS < 5 \|\| P > 1.e-15 ) && softInt_ );
	iH++;
	} while ( (iH < maxScatters_) && (iH < 5 \|\| P0 > 1.e-15) );
	}
	}


	// calculate the integrand
	Length Eikonalization::operator() (Length b) const {
	unsigned int Nhard(0), Nsoft(0);
	//fac is just: d^2b=fac*db despite that large number
	Length fac(Constants::twopi*b);

	double chiTot(( theHandler->OverlapFunction(b)*hardXSec_ +
	theHandler->OverlapFunction(b, softMu2_)*softXSec_ ) / 2.0);

	//total cross section wanted
	if(theoption == -2) return 2 * fac * ( 1 - exp(-chiTot) );
	//inelastic cross section
	if(theoption == -1) return fac * ( 1 - exp(- 2.0 * chiTot) );

	if(theoption >= 0){
	//encode multiplicities as: N_hard*100 + N_soft
	Nhard = theoption/100;
	Nsoft = theoption%100;

	if(theHandler->Algorithm() > 0){
	//P_n*sigma_hard: n-1 extra scatters + 1 hard scatterer != hardXSec_
	return fac * Nhard * theHandler->poisson(b, hardXSec_, Nhard) *
	theHandler->poisson(b, softXSec_, Nsoft, softMu2_);
	}else{
	//P_n*sigma_inel: n extra scatters
	return fac * theHandler->poisson(b, hardXSec_, Nhard) *
	theHandler->poisson(b, softXSec_, Nsoft, softMu2_);
	}

	}else{
	throw Exception() << "Parameter theoption in Struct Eikonalization in "
	<< "MPIHandler.cc has not allowed value"
	<< Exception::runerror;
	return 0.0*meter;
	}
	}

	InvEnergy2 slopeBisection::operator() (Energy2 softMu2) const {
	GSLBisection root;
	//single component model
	TotalXSecBisection fn(handler_, softMu2);
	try{
	softXSec_ = root.value(fn, 0millibarn, 5000millibarn);
	}catch(GSLBisection::IntervalError){
	throw Exception() << "MPIHandler 2-Component model didn't work out."
	<< Exception::runerror;
	}
	return handler_->slopeDiff(softXSec_, softMu2);
	}

	LengthDiff slopeInt::operator() (Length b) const {
	//fac is just: d^2b=fac*db
	Length fac(Constants::twopi*b);

	double chiTot(( handler_->OverlapFunction(b)*hardXSec_ +
	handler_->OverlapFunction(b, softMu2_)*softXSec_ ) / 2.0);

	InvEnergy2 b2 = sqr(b/hbarc);
	//B*sigma_tot
	return fac * b2 * ( 1 - exp(-chiTot) );
	}

	double MPIHandler::factorial (unsigned int n) const {

	double f[] = {1.,1.,2.,6.,24.,120.,720.,5040.,40320.,362880.,3.6288e6,
	3.99168e7,4.790016e8,6.2270208e9,8.71782912e10,1.307674368e12,
	2.0922789888e13,3.55687428096e14,6.402373705728e15,1.21645100408832e17,
	2.43290200817664e18,5.10909421717094e19,1.12400072777761e21,
	2.5852016738885e22,6.20448401733239e23,1.5511210043331e25,
	4.03291461126606e26,1.08888694504184e28,3.04888344611714e29,
	8.8417619937397e30,2.65252859812191e32,8.22283865417792e33,
	2.63130836933694e35,8.68331761881189e36,2.95232799039604e38,
	1.03331479663861e40,3.71993326789901e41,1.37637530912263e43,
	5.23022617466601e44,2.03978820811974e46,8.15915283247898e47,
	3.34525266131638e49,1.40500611775288e51,6.04152630633738e52,
	2.65827157478845e54,1.1962222086548e56,5.50262215981209e57,
	2.58623241511168e59,1.24139155925361e61,6.08281864034268e62,
	3.04140932017134e64,1.55111875328738e66,8.06581751709439e67,
	4.27488328406003e69,2.30843697339241e71,1.26964033536583e73,
	7.10998587804863e74,4.05269195048772e76,2.35056133128288e78,
	1.3868311854569e80,8.32098711274139e81,5.07580213877225e83,
	3.14699732603879e85,1.98260831540444e87,1.26886932185884e89,
	8.24765059208247e90,5.44344939077443e92,3.64711109181887e94,
	2.48003554243683e96,1.71122452428141e98,1.19785716699699e100,
	8.50478588567862e101,6.12344583768861e103,4.47011546151268e105,
	3.30788544151939e107,2.48091408113954e109,1.88549470166605e111,
	1.45183092028286e113,1.13242811782063e115,8.94618213078298e116,
	7.15694570462638e118,5.79712602074737e120,4.75364333701284e122,
	3.94552396972066e124,3.31424013456535e126,2.81710411438055e128,
	2.42270953836727e130,2.10775729837953e132,1.85482642257398e134,
	1.65079551609085e136,1.48571596448176e138,1.3520015276784e140,
	1.24384140546413e142,1.15677250708164e144,1.08736615665674e146,
	1.03299784882391e148,9.9167793487095e149,9.61927596824821e151,
	9.42689044888325e153,9.33262154439442e155,9.33262154439442e157};

	if(n > maxScatters_)
	throw Exception() << "MPIHandler::factorial called with too large argument"
	<< Exception::runerror;
	else
	return f[n];
	}

	InvArea MPIHandler::OverlapFunction(Length b, Energy2 mu2) const {
	if(mu2 == ZERO)
	mu2 = invRadius_;

	InvLength mu = sqrt(mu2)/hbarc;
	return (sqr(mu)/96/Constants::pi)pow(mub, 3)(gsl_sf_bessel_Kn(3, mub));
	}

	double MPIHandler::poisson(Length b, CrossSection sigma, unsigned int N, Energy2 mu2) const {
	if(sigma > 0*millibarn){
	return pow(OverlapFunction(b, mu2)*sigma, (double)N)/factorial(N)
	exp(-OverlapFunction(b, mu2)sigma);
	}else{
	return (N==0) ? 1.0 : 0.0;
	}
	}

	CrossSection MPIHandler::totalXSecDiff(CrossSection softXSec,
	Energy2 softMu2) const {
	GSLIntegrator integrator;
	Eikonalization integrand(this, -2, hardXSec_, softXSec, softMu2);
	Length bmax = 500.0*sqrt(millibarn);

	CrossSection tot = integrator.value(integrand, ZERO, bmax);
	return (tot-totalXSecExp());
	}

	InvEnergy2 MPIHandler::slopeDiff(CrossSection softXSec,
	Energy2 softMu2) const {
	GSLIntegrator integrator;
	Eikonalization integrand(this, -2, hardXSec_, softXSec, softMu2);
	Length bmax = 500.0*sqrt(millibarn);

	CrossSection tot = integrator.value(integrand, ZERO, bmax);

	slopeInt integrand2(this, hardXSec_, softXSec, softMu2);

	return integrator.value(integrand2, ZERO, bmax)/tot - slopeExp();
	}

	CrossSection MPIHandler::totalXSecExp() const {
	if(totalXSecExp_ != 0*millibarn)
	return totalXSecExp_;

	double pom_old = 0.0808;
	CrossSection coef_old = 21.7*millibarn;
	double pom_new_hard = 0.452;
	CrossSection coef_new_hard = 0.0139*millibarn;
	double pom_new_soft = 0.0667;
	CrossSection coef_new_soft = 24.22*millibarn;

	Energy energy(generator()->maximumCMEnergy());

	switch(DLmode_){
	case 1://old DL extrapolation
	return coef_old * pow(energy/GeV, 2*pom_old);
	break;

	case 2://old DL extrapolation fixed to CDF
	return 81.8millibarn pow(energy/1800.0/GeV, 2*pom_old);
	break;

	case 3://new DL extrapolation
	return coef_new_hard * pow(energy/GeV, 2*pom_new_hard) +
	coef_new_soft * pow(energy/GeV, 2*pom_new_soft);
	break;

	default:
	throw Exception() << "MPIHandler::totalXSecExp non-existing mode selected"
	<< Exception::runerror;
	}
	}

	InvEnergy2 MPIHandler::slopeExp() const{
	//Currently return the slope as calculated in the pomeron fit by
	//Donnachie & Landshoff
	Energy energy(generator()->maximumCMEnergy());
	//slope at
	Energy e_0 = 1800*GeV;
	InvEnergy2 b_0 = 17/GeV2;
	return b_0 + log(energy/e_0)/GeV2;
	}

	void MPIHandler::overrideUECuts() {
	- Ptmin_ = EEparamA_ * log(generator()->maximumCMEnergy() / EEparamB_);
	-
	+ if(energyExtrapolation_==1)
	+ Ptmin_ = EEparamA_ * log(generator()->maximumCMEnergy() / EEparamB_);
	+ else if(energyExtrapolation_==2)
	+ Ptmin_ = pT0_*pow(double(generator()->maximumCMEnergy()/refScale_),b_);
	+ else
	+ assert(false);
	// create a new SimpleKTCut object with the calculated ptmin value
	Ptr<SimpleKTCut>::pointer newUEktCut = new_ptr(SimpleKTCut(Ptmin_));
	newUEktCut->init();
	newUEktCut->initrun();

	// create a new Cuts object with MHatMin = 2 * Ptmin_
	CutsPtr newUEcuts = new_ptr(Cuts(2*Ptmin_));
	newUEcuts->add(dynamic_ptr_cast<tOneCutPtr>(newUEktCut));
	newUEcuts->init();
	newUEcuts->initrun();

	// replace the old Cuts object
	cuts()[0] = newUEcuts;
	}

	void MPIHandler::persistentOutput(PersistentOStream & os) const {
	os << theMultiplicities << theHandler
	<< theSubProcesses << theCuts << theProcessHandlers
	<< additionalMultiplicities_ << identicalToUE_
	<< ounit(PtOfQCDProc_, GeV) << ounit(Ptmin_, GeV)
	<< ounit(hardXSec_, millibarn) << ounit(softXSec_, millibarn)
	<< ounit(beta_, 1/GeV2)
	<< algorithm_ << ounit(invRadius_, GeV2)
	<< numSubProcs_ << colourDisrupt_ << softInt_ << twoComp_
	<< DLmode_ << ounit(totalXSecExp_, millibarn)
	- << energyExtrapolation_ << ounit(EEparamA_, GeV) << ounit(EEparamB_, GeV);
	+ << energyExtrapolation_ << ounit(EEparamA_, GeV) << ounit(EEparamB_, GeV)
	+ << ounit(refScale_,GeV) << ounit(pT0_,GeV) << b_;
	}

	void MPIHandler::persistentInput(PersistentIStream & is, int) {
	is >> theMultiplicities >> theHandler
	>> theSubProcesses >> theCuts >> theProcessHandlers
	>> additionalMultiplicities_ >> identicalToUE_
	>> iunit(PtOfQCDProc_, GeV) >> iunit(Ptmin_, GeV)
	>> iunit(hardXSec_, millibarn) >> iunit(softXSec_, millibarn)
	>> iunit(beta_, 1/GeV2)
	>> algorithm_ >> iunit(invRadius_, GeV2)
	>> numSubProcs_ >> colourDisrupt_ >> softInt_ >> twoComp_
	>> DLmode_ >> iunit(totalXSecExp_, millibarn)
	- >> energyExtrapolation_ >> iunit(EEparamA_, GeV) >> iunit(EEparamB_, GeV);
	+ >> energyExtrapolation_ >> iunit(EEparamA_, GeV) >> iunit(EEparamB_, GeV)
	+ >> iunit(refScale_,GeV) >> iunit(pT0_,GeV) >> b_;
	}

	ClassDescription<MPIHandler> MPIHandler::initMPIHandler;
	// Definition of the static class description member.

	void MPIHandler::Init() {

	static ClassDocumentation<MPIHandler> documentation
	("The MPIHandler class is the main administrator of the multiple interaction model",
	"The underlying event was simulated with an eikonal model for multiple partonic interactions."
	"Details can be found in Ref.~\\cite{Bahr:2008dy,Bahr:2009ek}.",
	"%\\cite{Bahr:2008dy}\n"
	"\\bibitem{Bahr:2008dy}\n"
	" M.~Bahr, S.~Gieseke and M.~H.~Seymour,\n"
	" ``Simulation of multiple partonic interactions in Herwig++,''\n"
	" JHEP {\\bf 0807}, 076 (2008)\n"
	" [arXiv:0803.3633 [hep-ph]].\n"
	" %%CITATION = JHEPA,0807,076;%%\n"
	"\\bibitem{Bahr:2009ek}\n"
	" M.~Bahr, J.~M.~Butterworth, S.~Gieseke and M.~H.~Seymour,\n"
	" ``Soft interactions in Herwig++,''\n"
	" arXiv:0905.4671 [hep-ph].\n"
	" %%CITATION = ARXIV:0905.4671;%%\n"
	);

	static RefVector<MPIHandler,SubProcessHandler> interfaceSubhandlers
	("SubProcessHandlers",
	"The list of sub-process handlers used in this EventHandler. ",
	&MPIHandler::theSubProcesses, -1, false, false, true, false, false);

	static RefVector<MPIHandler,Cuts> interfaceCuts
	("Cuts",
	"List of cuts used for the corresponding list of subprocesses. These cuts "
	"should not be overidden in individual sub-process handlers.",
	&MPIHandler::theCuts, -1, false, false, true, false, false);

	static Parameter<MPIHandler,Energy2> interfaceInvRadius
	("InvRadius",
	"The inverse hadron radius squared used in the overlap function",
	&MPIHandler::invRadius_, GeV2, 2.0GeV2, 0.2GeV2, 4.0*GeV2,
	true, false, Interface::limited);

	static ParVector<MPIHandler,int> interfaceadditionalMultiplicities
	("additionalMultiplicities",
	"specify the multiplicities of secondary hard processes (multiple parton scattering)",
	&MPIHandler::additionalMultiplicities_,
	-1, 0, 0, 3,
	false, false, true);

	static Parameter<MPIHandler,int> interfaceIdenticalToUE
	("IdenticalToUE",
	"Specify which of the hard processes is identical to the UE one (QCD dijets)",
	&MPIHandler::identicalToUE_, -1, 0, 0,
	false, false, Interface::nolimits);

	static Parameter<MPIHandler,Energy> interfacePtOfQCDProc
	("PtOfQCDProc",
	"Specify the value of the pt cutoff for the process that is identical to the UE one",
	&MPIHandler::PtOfQCDProc_, GeV, -1.0*GeV, ZERO, ZERO,
	false, false, Interface::nolimits);

	static Parameter<MPIHandler,double> interfacecolourDisrupt
	("colourDisrupt",
	"Fraction of connections to additional subprocesses, which are colour disrupted.",
	&MPIHandler::colourDisrupt_,
	0.0, 0.0, 1.0,
	false, false, Interface::limited);


	static Switch<MPIHandler,bool> interfacesoftInt
	("softInt",
	"Switch to enable soft interactions",
	&MPIHandler::softInt_, true, false, false);

	static SwitchOption interfacesoftIntYes
	(interfacesoftInt,
	"Yes",
	"enable the two component model",
	true);
	static SwitchOption interfacesoftIntNo
	(interfacesoftInt,
	"No",
	"disable the model",
	false);


	- static Switch<MPIHandler,bool> interEnergyExtrapolation
	+ static Switch<MPIHandler,unsigned int> interEnergyExtrapolation
	("EnergyExtrapolation",
	"Switch to ignore the cuts object at MPIHandler:Cuts[0]. "
	"Instead, extrapolate the pt cut according to "
	"ptmin = A * log (sqrt(s) / B)",
	- &MPIHandler::energyExtrapolation_, true, false, false);
	- static SwitchOption interEnergyExtrapolationYes
	+ &MPIHandler::energyExtrapolation_, 2, false, false);
	+ static SwitchOption interEnergyExtrapolationLog
	(interEnergyExtrapolation,
	- "Yes",
	- "Use the energy extrapolation.",
	- true);
	+ "Log",
	+ "Use energy extrapolation in ptmin = A * log (sqrt(s) / B).",
	+ 1);
	+ static SwitchOption interEnergyExtrapolationPower
	+ (interEnergyExtrapolation,
	+ "Power",
	+ "Use energy extrapolation in ptmin = A * log (sqrt(s) / B).",
	+ 2);
	static SwitchOption interEnergyExtrapolationNo
	(interEnergyExtrapolation,
	"No",
	"Use manually set value for the minimal pt, "
	"specified in MPIHandler:Cuts[0]:OneCuts[0]:MinKT.",
	- false);
	+ 0);

	static Parameter<MPIHandler,Energy> interfaceEEparamA
	("EEparamA",
	"Parameter A in the empirical parametrization "
	"ptmin = A * log (sqrt(s) / B)",
	&MPIHandler::EEparamA_, GeV, 0.6*GeV, ZERO, Constants::MaxEnergy,
	false, false, Interface::limited);

	static Parameter<MPIHandler,Energy> interfaceEEparamB
	("EEparamB",
	"Parameter B in the empirical parametrization "
	"ptmin = A * log (sqrt(s) / B)",
	&MPIHandler::EEparamB_, GeV, 39.0*GeV, ZERO, Constants::MaxEnergy,
	false, false, Interface::limited);

	static Switch<MPIHandler,bool> interfacetwoComp
	("twoComp",
	"switch to enable the model with a different radius for soft interactions",
	&MPIHandler::twoComp_, true, false, false);

	static SwitchOption interfacetwoCompYes
	(interfacetwoComp,
	"Yes",
	"enable the two component model",
	true);
	static SwitchOption interfacetwoCompNo
	(interfacetwoComp,
	"No",
	"disable the model",
	false);


	static Parameter<MPIHandler,CrossSection> interfaceMeasuredTotalXSec
	("MeasuredTotalXSec",
	"Value for the total cross section (assuming rho=0). If non-zero, this "
	"overwrites the Donnachie-Landshoff parametrizations.",
	&MPIHandler::totalXSecExp_, millibarn, 0.0millibarn, 0.0millibarn, 0*millibarn,
	false, false, Interface::lowerlim);


	static Switch<MPIHandler,unsigned int> interfaceDLmode
	("DLmode",
	"Choice of Donnachie-Landshoff parametrization for the total cross section.",
	&MPIHandler::DLmode_, 2, false, false);
	static SwitchOption interfaceDLmodeStandard
	(interfaceDLmode,
	"Standard",
	"Standard parametrization with s**0.08",
	1);
	static SwitchOption interfaceDLmodeCDF
	(interfaceDLmode,
	"CDF",
	"Standard parametrization but normalization fixed to CDF's measured value",
	2);
	static SwitchOption interfaceDLmodeNew
	(interfaceDLmode,
	"New",
	"Parametrization taking hard and soft pomeron contributions into account",
	3);

	+ static Parameter<MPIHandler,Energy> interfaceReferenceScale
	+ ("ReferenceScale",
	+ "The reference energy for power law energy extrapolation of pTmin",
	+ &MPIHandler::refScale_, GeV, 7000.0GeV, 0.0GeV, 20000.*GeV,
	+ false, false, Interface::limited);
	+
	+ static Parameter<MPIHandler,Energy> interfacepTmin0
	+ ("pTmin0",
	+ "The pTmin at the reference scale for power law extrapolation of pTmin.",
	+ &MPIHandler::pT0_, GeV, 3.11GeV, 0.0GeV, 10.0*GeV,
	+ false, false, Interface::limited);
	+
	+ static Parameter<MPIHandler,double> interfacePower
	+ ("Power",
	+ "The power for power law extrapolation of the pTmin cut-off.",
	+ &MPIHandler::b_, 0.21, 0.0, 10.0,
	+ false, false, Interface::limited);
	}
	diff --git a/UnderlyingEvent/MPIHandler.h b/UnderlyingEvent/MPIHandler.h
	--- a/UnderlyingEvent/MPIHandler.h
	+++ b/UnderlyingEvent/MPIHandler.h
	@@ -1,910 +1,914 @@
	// -- C++ --
	//
	// MPIHandler.h is a part of Herwig++ - A multi-purpose Monte Carlo event generator
	// Copyright (C) 2002-2011 The Herwig Collaboration
	//
	// Herwig++ is licenced under version 2 of the GPL, see COPYING for details.
	// Please respect the MCnet academic guidelines, see GUIDELINES for details.
	//
	#ifndef HERWIG_MPIHandler_H
	#define HERWIG_MPIHandler_H
	//
	// This is the declaration of the MPIHandler class.
	//
	#include "ThePEG/Interface/Interfaced.h"
	#include "ThePEG/Handlers/StandardEventHandler.h"
	#include "ThePEG/Repository/EventGenerator.h"
	#include "Herwig++/PDT/StandardMatchers.h"
	#include "Herwig++/Utilities/GSLBisection.h"
	//#include "Herwig++/Utilities/GSLMultiRoot.h"
	#include "Herwig++/Utilities/GSLIntegrator.h"
	#include "Herwig++/Shower/UEBase.h"

	#include <cassert>
	#include "ProcessHandler.h"
	#include "MPIHandler.fh"


	namespace Herwig {
	using namespace ThePEG;

	/** \ingroup UnderlyingEvent
	* \class MPIHandler
	* This class is responsible for generating additional
	* semi hard partonic interactions.
	*
	* \author Manuel B\"ahr
	*
	* @see \ref MPIHandlerInterfaces "The interfaces"
	* defined for MPIHandler.
	* @see ProcessHandler
	* @see ShowerHandler
	* @see HwRemDecayer
	*/

	class MPIHandler: public UEBase {

	/**
	* Maximum number of scatters
	*/
	static const unsigned int maxScatters_ = 99;

	/**
	* Class for the integration is a friend to access private members
	*/
	friend struct Eikonalization;
	friend struct TotalXSecBisection;
	friend struct slopeAndTotalXSec;
	friend struct slopeInt;
	friend struct slopeBisection;

	public:

	/** A vector of <code>SubProcessHandler</code>s. */
	typedef vector<SubHdlPtr> SubHandlerList;

	/** A vector of <code>Cut</code>s. */
	typedef vector<CutsPtr> CutsList;

	/** A vector of <code>ProcessHandler</code>s. */
	typedef vector<ProHdlPtr> ProcessHandlerList;

	/** A vector of cross sections. */
	typedef vector<CrossSection> XSVector;

	/** A pair of multiplicities: hard, soft. */
	typedef pair<unsigned int, unsigned int> MPair;

	/** @name Standard constructors and destructors. */
	//@{
	/**
	* The default constructor.
	*/
	MPIHandler(): softMult_(0), identicalToUE_(-1),
	PtOfQCDProc_(-1.0GeV), Ptmin_(-1.0GeV),
	hardXSec_(0millibarn), softXSec_(0millibarn),
	totalXSecExp_(0*millibarn),
	softMu2_(ZERO), beta_(100.0/GeV2),
	algorithm_(2), numSubProcs_(0),
	colourDisrupt_(0.0), softInt_(true), twoComp_(true),
	DLmode_(2), avgNhard_(0.0), avgNsoft_(0.0),
	- energyExtrapolation_(true), EEparamA_(0.6*GeV),
	- EEparamB_(37.5*GeV) {}
	+ energyExtrapolation_(2), EEparamA_(0.6*GeV),
	+ EEparamB_(37.5GeV), refScale_(7000.GeV),
	+ pT0_(3.11*GeV), b_(0.21) {}

	/**
	* The destructor.
	*/
	virtual ~MPIHandler(){}
	//@}

	public:

	/** @name Methods for the MPI generation. */
	//@{

	/*
	* @return true if for this beam setup MPI can be generated
	*/
	virtual bool beamOK() const;

	/**
	* Return true or false depending on whether soft interactions are enabled.
	*/
	virtual bool softInt() const {return softInt_;}

	/**
	* Get the soft multiplicity from the pretabulated multiplicity
	* distribution. Generated in multiplicity in the first place.
	* @return the number of extra soft events in this collision
	*/
	virtual unsigned int softMultiplicity() const {return softMult_;}

	/**
	* Sample from the pretabulated multiplicity distribution.
	* @return the number of extra events in this collision
	*/
	virtual unsigned int multiplicity(unsigned int sel=0);

	/**
	* Select a StandardXComb according to it's weight
	* @return that StandardXComb Object
	* @param sel is the subprocess that should be returned,
	* if more than one is specified.
	*/
	virtual tStdXCombPtr generate(unsigned int sel=0);
	//@}


	/** @name Functions used by the persistent I/O system. */
	//@{
	/**
	* Function used to write out object persistently.
	* @param os the persistent output stream written to.
	*/
	void persistentOutput(PersistentOStream & os) const;

	/**
	* Function used to read in object persistently.
	* @param is the persistent input stream read from.
	* @param version the version number of the object when written.
	*/
	void persistentInput(PersistentIStream & is, int version);
	//@}

	/**
	* The standard Init function used to initialize the interfaces.
	* Called exactly once for each class by the class description system
	* before the main function starts or
	* when this class is dynamically loaded.
	*/
	static void Init();

	/**
	* Initialize this Multiple Interaction handler and all related objects needed to
	* generate additional events.
	*/
	virtual void initialize();

	/**
	* Finalize this Multiple Interaction handler and all related objects needed to
	* generate additional events.
	*/
	virtual void finalize();

	/**
	* Write out accumulated statistics about integrated cross sections.
	*/
	void statistics() const;

	/**
	* The level of statistics. Controlls the amount of statistics
	* written out after each run to the <code>EventGenerator</code>s
	* <code>.out</code> file. Simply the EventHandler method is called here.
	*/
	int statLevel() const {return eventHandler()->statLevel();}

	/**
	* Return the hard cross section above ptmin
	*/
	CrossSection hardXSec() const { return hardXSec_; }

	/**
	* Return the soft cross section below ptmin
	*/
	CrossSection softXSec() const { return softXSec_; }

	/**
	* Return the inelastic cross section
	*/
	CrossSection inelasticXSec() const { return inelXSec_; }

	/** @name Simple access functions. */
	//@{

	/**
	* Return the ThePEG::EventHandler assigned to this handler.
	* This methods shadows ThePEG::StepHandler::eventHandler(), because
	* it is not virtual in ThePEG::StepHandler. This is ok, because this
	* method would give a null-pointer at some stages, whereas this method
	* gives access to the explicitely copied pointer (in initialize())
	* to the ThePEG::EventHandler.
	*/
	tEHPtr eventHandler() const {return theHandler;}

	/**
	* Return the current handler
	*/
	static const MPIHandler * currentHandler() {
	return currentHandler_;
	}

	/**
	* Return theAlgorithm.
	*/
	virtual int Algorithm() const {return algorithm_;}

	/**
	* Return the ptmin parameter of the model
	*/
	virtual Energy Ptmin() const {
	if(Ptmin_ > ZERO)
	return Ptmin_;
	else
	throw Exception() << "MPIHandler::Ptmin called without initialize before"
	<< Exception::runerror;
	}

	/**
	* Return the slope of the soft pt spectrum as calculated.
	*/
	virtual InvEnergy2 beta() const {
	if(beta_ != 100.0/GeV2)
	return beta_;
	else
	throw Exception() << "MPIHandler::beta called without initialization"
	<< Exception::runerror;
	}

	/**
	* Return the pt Cutoff of the Interaction that is identical to the UE
	* one.
	*/
	virtual Energy PtForVeto() const {return PtOfQCDProc_;}

	/**
	* Return the number of additional "hard" processes ( = multiple
	* parton scattering)
	*/
	virtual unsigned int additionalHardProcs() const {return numSubProcs_-1;}

	/**
	* Return the fraction of colour disrupted connections to the
	* suprocesses.
	*/
	virtual double colourDisrupt() const {return colourDisrupt_;}

	protected:

	/** @name Clone Methods. */
	//@{
	/**
	* Make a simple clone of this object.
	* @return a pointer to the new object.
	*/
	virtual IBPtr clone() const;

	/** Make a clone of this object, possibly modifying the cloned object
	* to make it sane.
	* @return a pointer to the new object.
	*/
	virtual IBPtr fullclone() const;
	//@}

	private:

	/**
	* Access the list of sub-process handlers.
	*/
	const SubHandlerList & subProcesses()
	const {return theSubProcesses;}

	/**
	* Access the list of sub-process handlers.
	*/
	SubHandlerList & subProcesses() {return theSubProcesses;}

	/**
	* Access the list of cuts.
	*/
	const CutsList & cuts() const {return theCuts;}

	/**
	* Access the list of cuts.
	*/
	CutsList & cuts() {return theCuts;}

	/**
	* Access the list of sub-process handlers.
	*/
	const ProcessHandlerList & processHandlers()
	const {return theProcessHandlers;}

	/**
	* Access the list of sub-process handlers.
	*/
	ProcessHandlerList & processHandlers() {return theProcessHandlers;}


	/**
	* Method to calculate the individual probabilities for N scatters in the event.
	* @param UEXSecs is(are) the inclusiv cross section(s) for the UE process(es).
	*/
	void Probs(XSVector UEXSecs);

	/**
	* Debug method to check the individual probabilities.
	* @param filename is the file the output gets written to
	*/
	void MultDistribution(string filename) const;

	/**
	* Return the value of the Overlap function A(b) for a given impact
	* parameter \a b.
	* @param b impact parameter
	* @param mu2 = inv hadron radius squared. 0 will use the value of
	* invRadius_
	* @return inverse area.
	*/
	InvArea OverlapFunction(Length b, Energy2 mu2=ZERO) const;

	/**
	* Method to calculate the poisson probability for expectation value
	* \f$<n> = A(b)\sigma\f$, and multiplicity N.
	*/
	double poisson(Length b, CrossSection sigma,
	unsigned int N, Energy2 mu2=ZERO) const;

	/**
	* Return n!
	*/
	double factorial (unsigned int n) const;

	/**
	* Returns the total cross section for the current CMenergy. The
	* decision which parametrization will be used is steered by a
	* external parameter of this class.
	*/
	CrossSection totalXSecExp() const;

	/**
	* Difference of the calculated total cross section and the
	* experimental one from totalXSecExp.
	* @param softXSec = the soft cross section that is used
	* @param softMu2 = the soft radius, if 0 the hard radius will be used
	*/
	CrossSection totalXSecDiff(CrossSection softXSec,
	Energy2 softMu2=ZERO) const;

	/**
	* Difference of the calculated elastic slope and the
	* experimental one from slopeExp.
	* @param softXSec = the soft cross section that is used
	* @param softMu2 = the soft radius, if 0 the hard radius will be used
	*/
	InvEnergy2 slopeDiff(CrossSection softXSec,
	Energy2 softMu2=ZERO) const;

	/**
	* Returns the value of the elastic slope for the current CMenergy.
	* The decision which parametrization will be used is steered by a
	* external parameter of this class.
	*/
	InvEnergy2 slopeExp() const;


	/**
	* Calculate the minimal transverse momentum from the extrapolation
	*/
	void overrideUECuts();


	private:

	/**
	* The static object used to initialize the description of this class.
	* Indicates that this is a concrete class with persistent data.
	*/
	static ClassDescription<MPIHandler> initMPIHandler;

	/**
	* The assignment operator is private and must never be called.
	* In fact, it should not even be implemented.
	*/
	MPIHandler & operator=(const MPIHandler &);

	/**
	* A pointer to the EventHandler that calls us. Has to be saved, because the
	* method eventHandler() inherited from ThePEG::StepHandler returns a null-pointer
	* sometimes. Leif changed that in r1053 so that a valid pointer is present, when
	* calling doinitrun().
	*/
	tEHPtr theHandler;

	/**
	* The list of <code>SubProcessHandler</code>s.
	*/
	SubHandlerList theSubProcesses;

	/**
	* The kinematical cuts used for this collision handler.
	*/
	CutsList theCuts;

	/**
	* List of ProcessHandler used to sample different processes independently
	*/
	ProcessHandlerList theProcessHandlers;

	/**
	* A ThePEG::Selector where the individual Probabilities P_N are stored
	* and the actual Multiplicities can be selected.
	*/
	Selector<MPair> theMultiplicities;

	/**
	* Variable to store the soft multiplicity generated for a event. This
	* has to be stored as it is generated at the time of the hard
	* additional interactions but used later on.
	*/
	unsigned int softMult_;

	/**
	* Variable to store the multiplicity of the second hard process
	*/
	vector<int> additionalMultiplicities_;

	/**
	* Variable to store the information, which process is identical to
	* the UE one (QCD dijets).
	* 0 means "real" hard one
	* n>0 means the nth additional hard scatter
	* -1 means no one!
	*/
	int identicalToUE_;

	/**
	* Variable to store the minimal pt of the process that is identical
	* to the UE one. This only has to be set, if it can't be determined
	* automatically (i.e. when reading QCD LesHouches files in).
	*/
	Energy PtOfQCDProc_;

	/**
	* Variable to store the parameter ptmin
	*/
	Energy Ptmin_;

	/**
	* Variable to store the hard cross section above ptmin
	*/
	CrossSection hardXSec_;

	/**
	* Variable to store the final soft cross section below ptmin
	*/
	CrossSection softXSec_;

	/**
	* Variable to store the inelastic cross section
	*/
	CrossSection inelXSec_;

	/**
	* Variable to store the total pp cross section (assuming rho=0!) as
	* measured at LHC. If this variable is set, this value is used in the
	* subsequent run instead of any of the Donnachie-Landshoff
	* parametrizations.
	*/
	CrossSection totalXSecExp_;

	/**
	* Variable to store the soft radius, that is calculated during
	* initialization for the two-component model.
	*/
	Energy2 softMu2_;

	/**
	* slope to the non-perturbative pt spectrum: \f$d\sigma/dp_T^2 = A \exp
	* (- beta p_T^2)\f$. Its value is determined durint initialization.
	*/
	InvEnergy2 beta_;
	/**
	* Switch to be set from outside to determine the algorithm used for
	* UE activity.
	*/
	int algorithm_;

	/**
	* Inverse hadron Radius squared \f$ (\mu^2) \f$. Used inside the overlap function.
	*/
	Energy2 invRadius_;

	/**
	* Member variable to store the actual number of separate SubProcesses
	*/
	unsigned int numSubProcs_;

	/**
	* Variable to store the relative number of colour disrupted
	* connections to additional subprocesses. This variable is used in
	* Herwig::HwRemDecayer but store here, to have access to all
	* parameters through one Object.
	*/
	double colourDisrupt_;

	/**
	* Flag to store whether soft interactions, i.e. pt < ptmin should be
	* simulated.
	*/
	bool softInt_;

	/**
	* Flag to steer wheather the soft part has a different radius, that
	* will be dynamically fixed.
	*/
	bool twoComp_;

	/**
	* Switch to determine which Donnachie & Landshoff parametrization
	* should be used.
	*/
	unsigned int DLmode_;

	/**
	* Variable to store the average hard multiplicity.
	*/
	double avgNhard_;

	/**
	* Variable to store the average soft multiplicity.
	*/
	double avgNsoft_;

	/**
	* The current handler
	*/
	static MPIHandler * currentHandler_;

	/**
	* Flag to store whether to calculate the minimal UE pt according to an
	* extrapolation formula or whether to use MPIHandler:Cuts[0]:OneCuts[0]:MinKT
	*/
	- bool energyExtrapolation_;
	+ unsigned int energyExtrapolation_;

	/**
	* Parameters for the energy extrapolation formula
	*/
	Energy EEparamA_;
	Energy EEparamB_;
	+ Energy refScale_;
	+ Energy pT0_;
	+ double b_;

	protected:

	/** @cond EXCEPTIONCLASSES */

	/**
	* Exception class used by the MultipleInteractionHandler, when something
	* during initialization went wrong.
	* \todo understand!!!
	*/
	class InitError: public Exception {};

	/** @endcond */

	};

	}

	#include "ThePEG/Utilities/ClassTraits.h"

	namespace ThePEG {

	/** @cond TRAITSPECIALIZATIONS */

	/** This template specialization informs ThePEG about the
	* base classes of MPIHandler. */
	template <>
	struct BaseClassTrait<Herwig::MPIHandler,1> {
	/** Typedef of the first base class of MPIHandler. */
	typedef Interfaced NthBase;
	};

	/** This template specialization informs ThePEG about the name of
	* the MPIHandler class and the shared object where it is defined. */
	template <>
	struct ClassTraits<Herwig::MPIHandler>
	: public ClassTraitsBase<Herwig::MPIHandler> {
	/** Return a platform-independent class name */
	static string className() { return "Herwig::MPIHandler"; }
	/** Return the name(s) of the shared library (or libraries) be loaded to get
	* access to the MPIHandler class and any other class on which it depends
	* (except the base class). */
	static string library() { return "SimpleKTCut.so HwMPI.so"; }
	};

	/** @endcond */

	}

	namespace Herwig {

	/**
	* A struct for the 2D root finding that is necessary to determine the
	* soft cross section and the soft radius that is needed to describe
	* the total cross section correctly.
	* NOT IN USE CURRENTLY
	*/
	struct slopeAndTotalXSec : public GSLHelper<CrossSection, CrossSection> {

	public:

	/**
	* Constructor
	*/
	slopeAndTotalXSec(tcMPIHPtr handler): handler_(handler) {}

	/** second argument type */
	typedef Energy2 ArgType2;

	/** second value type */
	typedef InvEnergy2 ValType2;

	/** first element of the vector like function to find root for
	* @param softXSec soft cross-section
	* @param softMu2 \f$\mu^2\f$
	*/
	CrossSection f1(ArgType softXSec, ArgType2 softMu2) const {
	return handler_->totalXSecDiff(softXSec, softMu2);
	}

	/** second element of the vector like function to find root for
	* @param softXSec soft cross-section
	* @param softMu2 \f$\mu^2\f$
	*/
	InvEnergy2 f2(ArgType softXSec, ArgType2 softMu2) const {
	return handler_->slopeDiff(softXSec, softMu2);
	}

	/** provide the actual units of use */
	virtual ValType vUnit() const {return 1.0*millibarn;}

	/** otherwise rounding errors may get significant */
	virtual ArgType aUnit() const {return 1.0*millibarn;}

	/** provide the actual units of use */
	ValType2 vUnit2() const {return 1.0/GeV2;}

	/** otherwise rounding errors may get significant */
	ArgType2 aUnit2() const {return GeV2;}

	private:

	/**
	* Pointer to the handler
	*/
	tcMPIHPtr handler_;

	};

	/**
	* A struct for the root finding that is necessary to determine the
	* slope of the soft pt spectrum to match the soft cross section
	*/
	struct betaBisection : public GSLHelper<Energy2, InvEnergy2>{
	public:
	/**
	* Constructor.
	* @param soft = soft cross section, i.e. the integral of the soft
	* pt spectrum f(u=p_T^2) = dsig exp(-beta*u/u_min)
	* @param dsig = dsigma_hard/dp_T^2 at the p_T cutoff
	* @param ptmin = p_T cutoff
	*/
	betaBisection(CrossSection soft, DiffXSec dsig, Energy ptmin)
	: softXSec_(soft), dsig_(dsig), ptmin_(ptmin) {}

	/**
	* Operator that is used inside the GSLBisection class
	*/
	virtual Energy2 operator ()(InvEnergy2 beta) const
	{
	if( fabs(beta*GeV2) < 1.E-4 )
	beta = (beta > ZERO) ? 1.E-4/GeV2 : -1.E-4/GeV2;

	return (exp(beta*sqr(ptmin_)) - 1.0)/beta - softXSec_/dsig_;
	}

	/** provide the actual units of use */
	virtual ValType vUnit() const {return 1.0*GeV2;}

	/** provide the actual units of use */
	virtual ArgType aUnit() const {return 1.0/GeV2;}

	private:

	/** soft cross section */
	CrossSection softXSec_;

	/** dsigma/dp_T^2 at ptmin */
	DiffXSec dsig_;

	/** pt cutoff */
	Energy ptmin_;
	};

	/**
	* A struct for the root finding that is necessary to determine the
	* soft cross section and soft mu2 that are needed to describe the
	* total cross section AND elastic slope correctly.
	*/
	struct slopeBisection : public GSLHelper<InvEnergy2, Energy2> {
	public:
	/** Constructor */
	slopeBisection(tcMPIHPtr handler) : handler_(handler) {}

	/**
	* Return the difference of the calculated elastic slope to the
	* experimental one for a given value of the soft mu2. During that,
	* the soft cross section get fixed.
	*/
	InvEnergy2 operator ()(Energy2 arg) const;

	/** Return the soft cross section that has been calculated */
	CrossSection softXSec() const {return softXSec_;}

	private:
	/** const pointer to the MPIHandler to give access to member functions.*/
	tcMPIHPtr handler_;
	/** soft cross section that is determined on the fly.*/
	mutable CrossSection softXSec_;
	};

	/**
	* A struct for the root finding that is necessary to determine the
	* soft cross section that is needed to describe the total cross
	* section correctly.
	*/
	struct TotalXSecBisection : public GSLHelper<CrossSection, CrossSection> {
	public:

	/**
	* Constructor
	* @param handler The handler
	* @param softMu2 \f$\mu^2\f$
	*/
	TotalXSecBisection(tcMPIHPtr handler, Energy2 softMu2=ZERO):
	handler_(handler), softMu2_(softMu2) {}

	/**
	* operator to return the cross section
	* @param argument input cross section
	*/
	CrossSection operator ()(CrossSection argument) const {
	return handler_->totalXSecDiff(argument, softMu2_);
	}

	/** provide the actual units of use */
	virtual ValType vUnit() const {return 1.0*millibarn;}

	/** otherwise rounding errors may get significant */
	virtual ArgType aUnit() const {return 1.0*millibarn;}

	private:

	/**
	* The handler
	*/
	tcMPIHPtr handler_;

	/**
	* \f$\mu^2\f$
	*/
	Energy2 softMu2_;

	};

	/**
	* Typedef for derivative of the length
	*/
	typedef QTY<1,-2,0>::Type LengthDiff;

	/**
	* A struct for the integrand for the slope
	*/
	struct slopeInt : public GSLHelper<LengthDiff, Length>{

	public:
	/** Constructor
	* @param handler The handler
	* @param hard The hard cross section
	* @param soft The soft cross section
	* @param softMu2 \f$\mu^2\f$
	*/
	slopeInt(tcMPIHPtr handler, CrossSection hard,
	CrossSection soft=0*millibarn, Energy2 softMu2=ZERO)
	: handler_(handler), hardXSec_(hard),
	softXSec_(soft), softMu2_(softMu2) {}

	/**
	* Operator to return the answer
	* @param arg The argument
	*/
	ValType operator ()(ArgType arg) const;

	private:

	/**
	* Pointer to the Handler that calls this integrand
	*/
	tcMPIHPtr handler_;

	/**
	* The hard cross section to be eikonalized
	*/
	CrossSection hardXSec_;

	/**
	* The soft cross section to be eikonalized. Default is zero
	*/
	CrossSection softXSec_;

	/**
	* The inv radius^2 of the soft interactions.
	*/
	Energy2 softMu2_;

	};

	/**
	* A struct for the eikonalization of the inclusive cross section.
	*/
	struct Eikonalization : public GSLHelper<Length, Length>{

	/**
	* The constructor
	* @param handler is the pointer to the MPIHandler to get access to
	* MPIHandler::OverlapFunction and member variables of the MPIHandler.
	* @param option is a flag, whether the inelastic or the total
	* @param handler The handler
	* @param hard The hard cross section
	* @param soft The soft cross section
	* @param softMu2 \f$\mu^2\f$
	* cross section should be returned (-2 or -1). For option = N > 0 the integrand
	* is N(A(b)sigma)^N/N! exp(-A(b)sigma) this is the P_Nsigma where
	* P_N is the Probability of having exactly N interaction (including the hard one)
	* This is equation 14 from "Jimmy4: Multiparton Interactions in HERWIG for the LHC"
	*/
	Eikonalization(tcMPIHPtr handler, int option, CrossSection hard,
	CrossSection soft=0*millibarn, Energy2 softMu2=ZERO)
	: theHandler(handler), theoption(option), hardXSec_(hard),
	softXSec_(soft), softMu2_(softMu2) {}

	/**
	* Get the function value
	*/
	Length operator ()(Length argument) const;

	private:
	/**
	* Pointer to the Handler that calls this integrand
	*/
	tcMPIHPtr theHandler;

	/**
	* A flag to switch between the calculation of total and inelastic cross section
	* or calculations for the individual probabilities. See the constructor
	*/
	int theoption;

	/**
	* The hard cross section to be eikonalized
	*/
	CrossSection hardXSec_;

	/**
	* The soft cross section to be eikonalized. Default is zero
	*/
	CrossSection softXSec_;

	/**
	* The inv radius^2 of the soft interactions.
	*/
	Energy2 softMu2_;

	};
	}


	#ifndef ThePEG_TEMPLATES_IN_CC_FILE
	// #include "MPIHandler.tcc"
	#endif

	#endif /* HERWIG_MPIHandler_H */

File Metadata

Mime Type: text/x-diff
Expires: Tue, Nov 19, 9:06 PM (22 h, 32 m)
Storage Engine: blob
Storage Format: Raw Data
Storage Handle: 3806200
Default Alt Text: (53 KB)

No OneTemporaryActions

View Options

File Metadata

Event Timeline

No OneTemporary
Actions