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	diff --git a/FixedOrderGen/include/PhaseSpacePoint.hh b/FixedOrderGen/include/PhaseSpacePoint.hh
	index f89ab03..4399492 100644
	--- a/FixedOrderGen/include/PhaseSpacePoint.hh
	+++ b/FixedOrderGen/include/PhaseSpacePoint.hh
	@@ -1,298 +1,322 @@
	/** \file PhaseSpacePoint.hh
	* \brief Contains the PhaseSpacePoint Class
	*
	* \authors The HEJ collaboration (see AUTHORS for details)
	* \date 2019-2020
	* \copyright GPLv2 or later
	*/
	#pragma once

	#include <array>
	#include <bitset>
	#include <cstddef>
	#include <unordered_map>
	+#include <optional>
	#include <vector>

	#include "boost/iterator/filter_iterator.hpp"

	#include "HEJ/Event.hh"
	#include "HEJ/PDG_codes.hh"
	#include "HEJ/Particle.hh"

	#include "fastjet/PseudoJet.hh"

	#include "Decay.hh"
	#include "Status.hh"
	#include "Subleading.hh"

	namespace HEJ {
	class EWConstants;
	class PDF;
	class RNG;
	}

	namespace HEJFOG {
	struct JetParameters;
	struct Process;

	//! A point in resummation phase space
	class PhaseSpacePoint{
	public:

	//! Iterator over partons
	using ConstPartonIterator = boost::filter_iterator<
	bool (*)(HEJ::Particle const &),
	std::vector<HEJ::Particle>::const_iterator
	>;
	//! Reverse Iterator over partons
	using ConstReversePartonIterator = std::reverse_iterator<
	ConstPartonIterator>;

	//! Default PhaseSpacePoint Constructor
	PhaseSpacePoint() = delete;

	//! PhaseSpacePoint Constructor
	/**
	* @param proc The process to generate
	* @param jet_param Jet defintion & cuts
	* @param pdf The pdf set (used for sampling)
	* @param E_beam Energie of the beam
	* @param subl_chance Chance to turn a potentially unordered
	* emission into an actual one
	* @param subl_channels Possible subleading channels.
	* see HEJFOG::Subleading
	* @param particle_properties Properties of producted boson
	*
	* Initially, only FKL phase space points are generated. subl_chance gives
	* the chance of turning one emissions into a subleading configuration,
	* i.e. either unordered or central quark/anti-quark pair. Unordered
	* emissions require that the most extremal emission in any direction is
	* a quark or anti-quark and the next emission is a gluon. Quark/anti-quark
	* pairs are only generated for W processes. At most one subleading
	* emission will be generated in this way.
	*/
	PhaseSpacePoint(
	Process const & proc,
	JetParameters const & jet_param,
	HEJ::PDF & pdf, double E_beam,
	double subl_chance,
	Subleading subl_channels,
	ParticlesDecayMap const & particle_decays,
	HEJ::EWConstants const & ew_parameters,
	HEJ::RNG & ran
	);

	//! Get Weight Function
	/**
	* @returns Weight of Event
	*/
	double weight() const{
	return weight_;
	}

	Status status() const{
	return status_;
	}

	//! Get Incoming Function
	/**
	* @returns Incoming Particles
	*/
	std::array<HEJ::Particle, 2> const & incoming() const{
	return incoming_;
	}

	//! Get Outgoing Function
	/**
	* @returns Outgoing Particles
	*/
	std::vector<HEJ::Particle> const & outgoing() const{
	return outgoing_;
	}

	std::unordered_map<std::size_t, std::vector<HEJ::Particle>> const & decays() const{
	return decays_;
	}

	//! Iterator to the first outgoing parton
	ConstPartonIterator begin_partons() const;
	//! Iterator to the first outgoing parton
	ConstPartonIterator cbegin_partons() const;

	//! Iterator to the end of the outgoing partons
	ConstPartonIterator end_partons() const;
	//! Iterator to the end of the outgoing partons
	ConstPartonIterator cend_partons() const;

	//! Reverse Iterator to the first outgoing parton
	ConstReversePartonIterator rbegin_partons() const;
	//! Reverse Iterator to the first outgoing parton
	ConstReversePartonIterator crbegin_partons() const;
	//! Reverse Iterator to the first outgoing parton
	ConstReversePartonIterator rend_partons() const;
	//! Reverse Iterator to the first outgoing parton
	ConstReversePartonIterator crend_partons() const;

	private:
	static constexpr std::size_t NUM_PARTONS = 11; //!< Number of partons
	public:
	using part_mask = std::bitset<NUM_PARTONS>; //!< Selection mask for partons
	private:
	friend HEJ::Event::EventData to_EventData(PhaseSpacePoint psp);
	/**
	* @internal
	* @brief Generate LO parton momentum
	*
	* @param np Number of partons to generate
	* @param is_pure_jets If true ensures momentum conservation in x and y
	* @param jet_param Jet properties to fulfil
	* @param max_pt max allowed pt for a parton (typically E_CMS)
	* @param ran Random Number Generator
	*
	* @returns Momentum of partons
	*
	* Ensures that each parton is in its own jet.
	* Generation is independent of parton flavour. Output is sorted in rapidity.
	*/
	std::vector<fastjet::PseudoJet> gen_LO_partons(
	int np, bool is_pure_jets,
	JetParameters const & jet_param,
	double max_pt,
	HEJ::RNG & ran
	);
	HEJ::Particle gen_boson(
	HEJ::ParticleID bosonid, double mass, double width,
	+ Process const & proc,
	+ std::optional<subleading::Channels> channel,
	HEJ::RNG & ran
	);
	double gen_V_boson_rapidity(HEJ::RNG & ran);
	- double gen_Higgs_rapidity(HEJ::RNG & ran);
	+ double gen_Higgs_rapidity(
	+ Process const & proc,
	+ std::optional<subleading::Channels> channel,
	+ HEJ::RNG & ran
	+ );
	template<class ParticleMomenta>
	fastjet::PseudoJet gen_last_momentum(
	ParticleMomenta const & other_momenta,
	double mass_square, double y
	) const;

	bool jets_ok(
	std::vector<fastjet::PseudoJet> const & Born_jets,
	std::vector<fastjet::PseudoJet> const & partons
	) const;
	/**
	* @internal
	* @brief Generate incoming partons according to the PDF
	*
	* @param uf Scale used in the PDF
	*/
	void reconstruct_incoming(
	Process const & proc,
	- double subl_chance, Subleading subl_channels,
	+ std::optional<subleading::Channels> channel,
	HEJ::PDF & pdf, double E_beam,
	double uf,
	HEJ::RNG & ran
	);
	HEJ::ParticleID generate_incoming_id(
	std::size_t beam_idx, double x, double uf, HEJ::PDF & pdf,
	part_mask allowed_partons, HEJ::RNG & ran
	);
	//! @brief Returns list of all allowed initial states partons
	std::array<part_mask,2> allowed_incoming(
	Process const & proc,
	- double subl_chance, Subleading subl_channels,
	+ std::optional<subleading::Channels> channel,
	HEJ::RNG & ran
	);

	//! Ensure that incoming state compatible with A/W/Z production
	+ //! Should not be called for final-state qqbar configurations,
	+ //! since A/W/Z emission doesn't constrain the initial state there
	std::array<part_mask,2> incoming_AWZ(
	- Process const & proc, Subleading subl_channels,
	+ Process const & proc,
	std::array<part_mask,2> allowed_partons,
	HEJ::RNG & ran
	);
	//! Ensure that incoming state compatible with extremal qqbar
	std::array<part_mask,2> incoming_eqqbar(
	std::array<part_mask,2> allowed_partons, HEJ::RNG & ran);
	//! Ensure that incoming state compatible with unordered
	std::array<part_mask,2> incoming_uno(
	std::array<part_mask,2> allowed_partons, HEJ::RNG & ran);

	bool momentum_conserved(double ep) const;

	bool extremal_FKL_ok(
	std::vector<fastjet::PseudoJet> const & partons
	) const;
	double random_normal(double stddev, HEJ::RNG & ran);
	+ double random_normal_trunc(
	+ double stddev,
	+ HEJ::RNG & ran,
	+ double min,
	+ double max
	+ );
	/**
	* @internal
	* @brief Turns a FKL configuration into a subleading one
	*
	* @param chance Chance to switch to subleading configuration
	* @param channels Allowed channels for subleading process
	* @param proc Process to decide which subleading
	* configurations are allowed
	*
	* With a chance of "chance" the FKL configuration is either turned into
	* a unordered configuration or, for A/W/Z bosons, a configuration with
	* a central quark/anti-quark pair.
	*/
	- void maybe_turn_to_subl(double chance, Subleading channels,
	- Process const & proc, HEJ::RNG & ran);
	+ void turn_to_subl(
	+ subleading::Channels channel,
	+ Process const & proc,
	+ HEJ::RNG & ran
	+ );
	void turn_to_subl(
	Subleading channels,
	bool can_be_uno_backward, bool can_be_uno_forward, bool allow_strange,
	HEJ::RNG & ran);
	void turn_to_uno(bool can_be_uno_backward, bool can_be_uno_forward,
	HEJ::RNG & ran);
	HEJ::ParticleID select_qqbar_flavour(bool allow_strange, HEJ::RNG & ran);
	void turn_to_cqqbar(bool allow_strange, HEJ::RNG & ran);
	void turn_to_eqqbar(bool allow_strange, HEJ::RNG & ran);
	//! decay where we select the decay channel
	std::vector<HEJ::Particle> decay_channel(
	HEJ::Particle const & parent,
	std::vector<Decay> const & decays,
	HEJ::RNG & ran
	);
	/// @brief setup outgoing partons to ensure correct coupling to boson
	void couple_boson(HEJ::ParticleID boson, HEJ::RNG & ran);
	Decay select_decay_channel(
	std::vector<Decay> const & decays,
	HEJ::RNG & ran
	);
	double gen_hard_pt(
	int np, double ptmin, double ptmax, double y,
	HEJ::RNG & ran
	);
	double gen_soft_pt(int np, double max_pt, HEJ::RNG & ran);
	double gen_parton_pt(
	int count, JetParameters const & jet_param, double max_pt, double y,
	HEJ::RNG & ran
	);

	//! Iterator over partons (non-const)
	using PartonIterator = boost::filter_iterator<
	bool (*)(HEJ::Particle const &),
	std::vector<HEJ::Particle>::iterator
	>;
	//! Reverse Iterator over partons (non-const)
	using ReversePartonIterator = std::reverse_iterator<PartonIterator>;

	//! Iterator to the first outgoing parton (non-const)
	PartonIterator begin_partons();
	//! Iterator to the end of the outgoing partons (non-const)
	PartonIterator end_partons();

	//! Reverse Iterator to the first outgoing parton (non-const)
	ReversePartonIterator rbegin_partons();
	//! Reverse Iterator to the first outgoing parton (non-const)
	ReversePartonIterator rend_partons();

	+ std::optional<subleading::Channels> select_channel(
	+ Subleading subl_channels,
	+ double chance,
	+ HEJ::RNG & ran
	+ );
	+
	double weight_;

	Status status_;

	std::array<HEJ::Particle, 2> incoming_;
	std::vector<HEJ::Particle> outgoing_;
	//! Particle decays in the format {outgoing index, decay products}
	std::unordered_map<std::size_t, std::vector<HEJ::Particle>> decays_;
	};

	//! Extract HEJ::Event::EventData from PhaseSpacePoint
	HEJ::Event::EventData to_EventData(PhaseSpacePoint psp);
	} // namespace HEJFOG
	diff --git a/FixedOrderGen/src/PhaseSpacePoint.cc b/FixedOrderGen/src/PhaseSpacePoint.cc
	index 459fb1f..7ba2e7b 100644
	--- a/FixedOrderGen/src/PhaseSpacePoint.cc
	+++ b/FixedOrderGen/src/PhaseSpacePoint.cc
	@@ -1,1003 +1,1032 @@
	/**
	* \authors The HEJ collaboration (see AUTHORS for details)
	* \date 2019-2020
	* \copyright GPLv2 or later
	*/
	#include "PhaseSpacePoint.hh"

	#include <algorithm>
	#include <cassert>
	#include <cmath>
	+#include <cstdint>
	#include <cstdlib>
	#include <iostream>
	#include <iterator>
	#include <limits>
	#include <tuple>
	#include <type_traits>
	#include <utility>

	+#include "Subleading.hh"
	#include "fastjet/ClusterSequence.hh"

	#include "HEJ/Constants.hh"
	#include "HEJ/EWConstants.hh"
	#include "HEJ/PDF.hh"
	#include "HEJ/PDG_codes.hh"
	#include "HEJ/Particle.hh"
	#include "HEJ/RNG.hh"
	#include "HEJ/exceptions.hh"
	#include "HEJ/kinematics.hh"
	#include "HEJ/utility.hh"

	#include "JetParameters.hh"
	#include "Process.hh"

	namespace HEJFOG {
	HEJ::Event::EventData to_EventData(PhaseSpacePoint psp){
	//! @TODO Same function already in HEJ
	HEJ::Event::EventData result;
	result.incoming = std::move(psp).incoming_; // NOLINT(bugprone-use-after-move)
	result.outgoing = std::move(psp).outgoing_; // NOLINT(bugprone-use-after-move)
	// technically Event::EventData doesn't have to be sorted,
	// but PhaseSpacePoint should be anyway
	assert(
	std::is_sorted(
	begin(result.outgoing), end(result.outgoing),
	HEJ::rapidity_less{}
	)
	);
	assert(result.outgoing.size() >= 2);
	result.decays = std::move(psp).decays_; // NOLINT(bugprone-use-after-move)
	static_assert(
	std::numeric_limits<double>::has_quiet_NaN,
	"no quiet NaN for double"
	);
	constexpr double nan = std::numeric_limits<double>::quiet_NaN();
	result.parameters.central = {nan, nan, psp.weight()}; // NOLINT(bugprone-use-after-move)
	return result;
	}

	PhaseSpacePoint::ConstPartonIterator PhaseSpacePoint::begin_partons() const {
	return cbegin_partons();
	}
	PhaseSpacePoint::ConstPartonIterator PhaseSpacePoint::cbegin_partons() const {
	return {HEJ::is_parton, cbegin(outgoing()), cend(outgoing())};
	}

	PhaseSpacePoint::ConstPartonIterator PhaseSpacePoint::end_partons() const {
	return cend_partons();
	}
	PhaseSpacePoint::ConstPartonIterator PhaseSpacePoint::cend_partons() const {
	return {HEJ::is_parton, cend(outgoing()), cend(outgoing())};
	}

	PhaseSpacePoint::ConstReversePartonIterator PhaseSpacePoint::rbegin_partons() const {
	return crbegin_partons();
	}
	PhaseSpacePoint::ConstReversePartonIterator PhaseSpacePoint::crbegin_partons() const {
	return std::reverse_iterator<ConstPartonIterator>( cend_partons() );
	}

	PhaseSpacePoint::ConstReversePartonIterator PhaseSpacePoint::rend_partons() const {
	return crend_partons();
	}
	PhaseSpacePoint::ConstReversePartonIterator PhaseSpacePoint::crend_partons() const {
	return std::reverse_iterator<ConstPartonIterator>( cbegin_partons() );
	}

	PhaseSpacePoint::PartonIterator PhaseSpacePoint::begin_partons() {
	return {HEJ::is_parton, begin(outgoing_), end(outgoing_)};
	}

	PhaseSpacePoint::PartonIterator PhaseSpacePoint::end_partons() {
	return {HEJ::is_parton, end(outgoing_), end(outgoing_)};
	}

	PhaseSpacePoint::ReversePartonIterator PhaseSpacePoint::rbegin_partons() {
	return std::reverse_iterator<PartonIterator>( end_partons() );
	}

	PhaseSpacePoint::ReversePartonIterator PhaseSpacePoint::rend_partons() {
	return std::reverse_iterator<PartonIterator>( begin_partons() );
	}

	namespace {
	bool can_swap_to_uno(
	HEJ::Particle const & p1, HEJ::Particle const & p2
	){
	assert(is_parton(p1) && is_parton(p2));
	return p1.type != HEJ::pid::gluon
	&& p2.type == HEJ::pid::gluon;
	}

	- size_t count_gluons(PhaseSpacePoint::ConstPartonIterator first,
	- PhaseSpacePoint::ConstPartonIterator last
	- ){
	- return std::count_if(first, last, [](HEJ::Particle const & p)
	- {return p.type == HEJ::pid::gluon;});
	- }
	-
	- /** assumes FKL configurations between first and last,
	- * else there can be a quark in a non-extreme position
	- * e.g. uno configuration gqg would pass
	- */
	- Subleading possible_qqbar(
	- PhaseSpacePoint::ConstPartonIterator first,
	- PhaseSpacePoint::ConstReversePartonIterator const & last
	- ){
	- using namespace subleading;
	- assert( std::distance( first,last.base() )>2 );
	- Subleading channels = ALL;
	- channels.reset(eqqbar);
	- channels.reset(cqqbar);
	- auto const ngluon = count_gluons(first,last.base());
	- if(ngluon < 2) return channels;
	- if(first->type==HEJ::pid::gluon \|\| last->type==HEJ::pid::gluon){
	- channels.set(eqqbar);
	- }
	- if(std::distance(first,last.base())>=4){
	- channels.set(cqqbar);
	- }
	- return channels;
	- }
	-
	template<class PartonIt, class OutIt>
	bool uno_possible(
	PartonIt first_parton, OutIt first_out
	){
	using namespace HEJ;
	// Special case: Higgs can not be outside of uno
	if(first_out->type == pid::Higgs
	\|\| std::next(first_out)->type==pid::Higgs){
	return false;
	}
	// decide what kind of subleading process is allowed
	return can_swap_to_uno( first_parton, std::next(first_parton) );
	}

	bool is_AWZ_proccess(Process const & proc){
	return proc.boson && HEJ::is_AWZ_boson(*proc.boson);
	}

	bool is_up_type(HEJ::Particle const & part){
	return is_anyquark(part) && ((std::abs(part.type)%2) == 0);
	}
	bool is_down_type(HEJ::Particle const & part){
	return is_anyquark(part) && ((std::abs(part.type)%2) != 0);
	}
	bool can_couple_to_W(
	HEJ::Particle const & part, HEJ::pid::ParticleID const W_id
	){
	const int W_charge = W_id>0?1:-1;
	return std::abs(part.type)<HEJ::pid::b
	&& ( (W_charge*part.type > 0 && is_up_type(part))
	\|\| (W_charge*part.type < 0 && is_down_type(part)) );
	}
	-
	- Subleading ensure_AWZ(
	- double & subl_chance, bool & allow_strange,
	- HEJ::ParticleID const boson,
	- PhaseSpacePoint::ConstPartonIterator first_parton,
	- PhaseSpacePoint::ConstPartonIterator last_parton
	- ){
	- auto channels = subleading::ALL;
	- if(std::none_of(first_parton, last_parton,
	- [&boson](HEJ::Particle const & p){
	- return can_couple_to_W(p, boson);})) {
	- // enforce qqbar if A/W/Z can't couple somewhere else
	- // this is ensured to work through filter_partons in reconstruct_incoming
	- channels.reset(subleading::uno);
	- assert(channels.any());
	- subl_chance = 1.;
	- // strange not allowed for W
	- if(std::abs(boson)== HEJ::pid::Wp) allow_strange = false;
	- }
	- return channels;
	- }
	} // namespace

	- void PhaseSpacePoint::turn_to_subl(
	- Subleading const channels,
	- bool const can_be_uno_backward, bool const can_be_uno_forward,
	- bool const allow_strange,
	- HEJ::RNG & ran
	- ){
	- double const nchannels = channels.count();
	- double const step = 1./nchannels;
	- weight_*=nchannels;
	- unsigned selected = subleading::first;
	- double rnd = nchannels>1?ran.flat():0.;
	- // @TODO optimise this sampling
	- for(; selected<=subleading::last; ++selected){
	- assert(rnd>=0);
	- if(channels[selected]){
	- if(rnd<step) break;
	- rnd-=step;
	- }
	- }
	- switch(selected){
	- case subleading::uno:
	- return turn_to_uno(can_be_uno_backward, can_be_uno_forward, ran);
	- case subleading::cqqbar:
	- return turn_to_cqqbar(allow_strange, ran);
	- case subleading::eqqbar:
	- return turn_to_eqqbar(allow_strange, ran);
	- default:
	- throw std::logic_error{"unreachable"};
	+ namespace {
	+ template<class Iterator>
	+ bool allow_strange(
	+ Iterator first_parton, Iterator last_parton,
	+ Process const & proc
	+ ) {
	+ const auto boson = proc.boson;
	+ return !(
	+ boson
	+ && std::abs(*boson)== HEJ::pid::Wp
	+ && std::none_of(
	+ first_parton, last_parton,
	+ [boson](HEJ::Particle const & p){
	+ return can_couple_to_W(p, *boson);
	+ })
	+ );
	}
	}

	- void PhaseSpacePoint::maybe_turn_to_subl(
	- double chance, Subleading channels, Process const & proc, HEJ::RNG & ran
	- ){
	+ void PhaseSpacePoint::turn_to_subl(
	+ subleading::Channels const channel,
	+ Process const & proc,
	+ HEJ::RNG & ran
	+ ) {
	using namespace HEJ;
	- if(proc.njets <= 2) return;
	- assert(outgoing_.size() >= 2);
	+ assert(proc.njets > 2);

	- // decide what kind of subleading process is allowed
	- bool const can_be_uno_backward = uno_possible(cbegin_partons(),
	+ switch(channel) {
	+ case subleading::unordered: {
	+ bool const can_be_uno_backward = uno_possible(cbegin_partons(),
	outgoing_.cbegin());
	- bool const can_be_uno_forward = uno_possible(crbegin_partons(),
	+ bool const can_be_uno_forward = uno_possible(crbegin_partons(),
	outgoing_.crbegin());
	- if(channels[subleading::uno]){
	- channels.set(subleading::uno, can_be_uno_backward \|\| can_be_uno_forward);
	+ return turn_to_uno(can_be_uno_backward, can_be_uno_forward, ran);
	}
	- channels &= possible_qqbar(cbegin_partons(), crbegin_partons());
	-
	- bool allow_strange = true;
	- if(is_AWZ_proccess(proc)) {
	- channels &= ensure_AWZ(chance, allow_strange, *proc.boson,
	- cbegin_partons(), cend_partons());
	+ case subleading::central_qqbar: {
	+ bool const strange_allowed = allow_strange(
	+ begin_partons(),
	+ end_partons(),
	+ proc
	+ );
	+ return turn_to_cqqbar(strange_allowed, ran);
	}
	-
	- std::size_t const nchannels = channels.count();
	- // no subleading
	- if(nchannels==0) return;
	- if(ran.flat() >= chance){
	- weight_ /= 1 - chance;
	- return;
	+ case subleading::extremal_qqbar: {
	+ bool const strange_allowed = allow_strange(
	+ begin_partons(),
	+ end_partons(),
	+ proc
	+ );
	+ return turn_to_eqqbar(strange_allowed, ran);
	}
	- weight_ /= chance;
	-
	- // select channel
	- return turn_to_subl( channels, can_be_uno_backward, can_be_uno_forward,
	- allow_strange, ran);
	+ default:;
	+ }
	+ throw std::logic_error{"enum value not covered"};
	}

	void PhaseSpacePoint::turn_to_uno(
	const bool can_be_uno_backward, const bool can_be_uno_forward,
	HEJ::RNG & ran
	){
	- if(!can_be_uno_backward && !can_be_uno_forward) return;
	if(can_be_uno_backward && can_be_uno_forward){
	weight_ *= 2.;
	if(ran.flat() < 0.5){
	return std::swap(begin_partons()->type, std::next(begin_partons())->type);
	}
	return std::swap(rbegin_partons()->type, std::next(rbegin_partons())->type);
	}
	if(can_be_uno_backward){
	return std::swap(begin_partons()->type, std::next(begin_partons())->type);
	}
	assert(can_be_uno_forward);
	std::swap(rbegin_partons()->type, std::next(rbegin_partons())->type);
	}

	//! select flavour of quark
	HEJ::ParticleID PhaseSpacePoint::select_qqbar_flavour(
	const bool allow_strange, HEJ::RNG & ran
	){
	const double r1 = 2.*ran.flat()-1.;
	const double max_flavour = allow_strange?HEJ::N_F:HEJ::N_F-1;
	weight_ = max_flavour2;
	double const flavour = HEJ::pid::down + std::floor(std::abs(r1)*max_flavour);
	return static_cast<HEJ::ParticleID>(flavour*(r1<0.?-1:1));
	}

	void PhaseSpacePoint::turn_to_cqqbar(const bool allow_strange, HEJ::RNG & ran){
	// we assume all FKL partons to be gluons
	auto first = std::next(begin_partons());
	auto last = std::next(rbegin_partons());
	auto const ng = std::distance(first, last.base());
	if(ng < 2)
	throw std::logic_error("not enough gluons to create qqbar");
	auto flavour = select_qqbar_flavour(allow_strange, ran);
	// select gluon for switch
	if(ng!=2){
	const double steps = 1./(ng-1.);
	weight_ /= steps;
	for(auto rnd = ran.flat(); rnd>steps; ++first){
	rnd-=steps;
	}
	}
	first->type = flavour;
	std::next(first)->type = anti(flavour);
	}

	void PhaseSpacePoint::turn_to_eqqbar(const bool allow_strange, HEJ::RNG & ran){
	/// find first and last gluon in FKL chain
	auto first = begin_partons();
	const bool can_forward = !is_anyquark(*first);
	auto last = rbegin_partons();
	const bool can_backward = !is_anyquark(*last);
	if(std::distance(first, last.base()) < 2)
	throw std::logic_error("not enough gluons to create qqbar");
	auto flavour = select_qqbar_flavour(allow_strange, ran);
	// select gluon for switch
	if(can_forward && !can_backward){
	first->type = flavour;
	std::next(first)->type = anti(flavour);
	return;
	}
	if(!can_forward && can_backward){
	last->type = flavour;
	std::next(last)->type = anti(flavour);
	return;
	}
	assert(can_forward && can_backward);
	weight_*=2.;
	if(ran.flat()>0.5){
	first->type = flavour;
	std::next(first)->type = anti(flavour);
	return;
	}
	last->type = flavour;
	std::next(last)->type = anti(flavour);
	}

	template<class ParticleMomenta>
	fastjet::PseudoJet PhaseSpacePoint::gen_last_momentum(
	ParticleMomenta const & other_momenta,
	const double mass_square, const double y
	) const {
	std::array<double,2> pt{0.,0.};
	for (auto const & p: other_momenta) {
	pt[0]-= p.px();
	pt[1]-= p.py();
	}

	const double mperp = std::sqrt(pt[0]pt[0]+pt[1]pt[1]+mass_square);
	const double pz=mperp*std::sinh(y);
	const double E=mperp*std::cosh(y);

	return {pt[0], pt[1], pz, E};
	}

	Decay PhaseSpacePoint::select_decay_channel(
	std::vector<Decay> const & decays,
	HEJ::RNG & ran
	){
	double br_total = 0.;
	for(auto const & decay: decays) br_total += decay.branching_ratio;
	// adjust weight
	// this is given by (channel branching ratio)/(chance to pick channel)
	// where (chance to pick channel) =
	// (channel branching ratio)/(total branching ratio)
	weight_ *= br_total;
	if(decays.size()==1) return decays.front();
	const double r1 = br_total*ran.flat();
	double br_sum = 0.;
	for(auto const & decay: decays){
	br_sum += decay.branching_ratio;
	if(r1 < br_sum) return decay;
	}
	throw std::logic_error{"unreachable"};
	}
	namespace {
	//! generate decay products of a boson
	std::vector<HEJ::Particle> decay_boson(
	HEJ::Particle const & parent,
	std::vector<HEJ::ParticleID> const & decays,
	HEJ::RNG & ran
	){
	if(decays.size() != 2){
	throw HEJ::not_implemented{
	"only decays into two particles are implemented"
	};
	}
	std::vector<HEJ::Particle> decay_products(decays.size());
	for(size_t i = 0; i < decays.size(); ++i){
	decay_products[i].type = decays[i];
	}
	// choose polar and azimuth angle in parent rest frame
	const double E = parent.m()/2;
	const double theta = 2.M_PIran.flat();
	const double cos_phi = 2.*ran.flat()-1.; // Jacobian Factors for W in line 418
	const double sin_phi = std::sqrt(1. - cos_phi*cos_phi); // Know 0 < phi < pi
	const double px = Estd::cos(theta)sin_phi;
	const double py = Estd::sin(theta)sin_phi;
	const double pz = E*cos_phi;
	decay_products[0].p.reset(px, py, pz, E);
	decay_products[1].p.reset(-px, -py, -pz, E);
	for(auto & particle: decay_products) particle.p.boost(parent.p);
	return decay_products;
	}
	} // namespace

	std::vector<HEJ::Particle> PhaseSpacePoint::decay_channel(
	HEJ::Particle const & parent,
	std::vector<Decay> const & decays,
	HEJ::RNG & ran
	){
	const auto channel = select_decay_channel(decays, ran);
	return decay_boson(parent, channel.products, ran);
	}

	namespace {
	//! adds a particle to target (in correct rapidity ordering)
	//! @returns positon of insertion
	auto insert_particle(std::vector<HEJ::Particle> & target,
	HEJ::Particle && particle
	){
	const auto pos = std::upper_bound(
	begin(target),end(target),particle,HEJ::rapidity_less{}
	);
	target.insert(pos, std::move(particle));
	return pos;
	}
	} // namespace

	PhaseSpacePoint::PhaseSpacePoint(
	Process const & proc,
	JetParameters const & jet_param,
	HEJ::PDF & pdf, double E_beam,
	double const subl_chance,
	- Subleading subl_channels,
	+ Subleading const subl_channels,
	ParticlesDecayMap const & particle_decays,
	HEJ::EWConstants const & ew_parameters,
	HEJ::RNG & ran
	){
	assert(proc.njets >= 2);
	status_ = Status::good;
	weight_ = 1;

	// ensure that all setting are consistent
	- if(subl_chance == 0.)
	- subl_channels.reset();
	+ // a more thorough check is in EventGenerator
	+ assert(subl_chance > 0. \|\| subl_channels.none());

	const std::size_t nout = proc.njets + (proc.boson?1:0)
	+ proc.boson_decay.size();
	outgoing_.reserve(nout);

	// generate parton momenta
	const bool is_pure_jets = (nout == proc.njets);
	auto partons = gen_LO_partons(
	proc.njets, is_pure_jets, jet_param, E_beam, ran
	);
	+ if(status_ != Status::good) return;
	// pre fill flavour with gluons
	- for( auto it = std::make_move_iterator(partons.begin());
	- it != std::make_move_iterator(partons.end());
	- ++it
	- ){
	- outgoing_.emplace_back(HEJ::Particle{HEJ::pid::gluon, *it, {}});
	+ for(auto && parton: std::move(partons)){
	+ outgoing_.emplace_back(HEJ::Particle{HEJ::pid::gluon, std::move(parton), {}});
	}
	- if(status_ != Status::good) return;
	+
	+ const std::optional<subleading::Channels> channel = select_channel(
	+ subl_channels,
	+ subl_chance,
	+ ran
	+ );

	if(proc.boson){ // decay boson
	auto const & boson_prop = (*proc.boson == HEJ::pid::Z_photon_mix
	? ew_parameters.prop(HEJ::pid::Z)
	: ew_parameters.prop(*proc.boson));
	- auto boson{ gen_boson(*proc.boson, boson_prop.mass, boson_prop.width, ran) };
	+ auto boson = gen_boson(
	+ *proc.boson, boson_prop.mass, boson_prop.width,
	+ proc,
	+ channel,
	+ ran
	+ );
	const auto pos{insert_particle(outgoing_, std::move(boson))};
	const size_t boson_idx = std::distance(begin(outgoing_), pos);
	auto const & boson_decay = particle_decays.find(*proc.boson);
	if( !proc.boson_decay.empty() ){ // decay given in proc
	decays_.emplace(
	boson_idx,
	decay_boson(outgoing_[boson_idx], proc.boson_decay, ran)
	);
	} else if( boson_decay != particle_decays.end()
	&& !boson_decay->second.empty() ){ // decay given explicitly
	decays_.emplace(
	boson_idx,
	decay_channel(outgoing_[boson_idx], boson_decay->second, ran)
	);
	}
	}
	// normalisation of momentum-conserving delta function
	weight_ = std::pow(2M_PI, 4);

	/** @TODO
	* uf (jet_param.min_pt) doesn't correspond to our final scale choice.
	* The HEJ scale generators currently expect a full event as input,
	* so fixing this is not completely trivial
	*/
	- reconstruct_incoming(proc, subl_chance, subl_channels, pdf, E_beam, jet_param.min_pt, ran);
	+ reconstruct_incoming(proc, channel, pdf, E_beam, jet_param.min_pt, ran);
	if(status_ != Status::good) return;
	// set outgoing states
	begin_partons()->type = incoming_[0].type;
	rbegin_partons()->type = incoming_[1].type;

	- maybe_turn_to_subl(subl_chance, subl_channels, proc, ran);
	+ if(channel) turn_to_subl(*channel, proc, ran);

	if(proc.boson) couple_boson(*proc.boson, ran);
	}

	// pt generation, see eq:pt_sampling in developer manual
	double PhaseSpacePoint::gen_hard_pt(
	const int np , const double ptmin, const double ptmax, const double /* y */,
	HEJ::RNG & ran
	){
	// heuristic parameter for pt sampling, see eq:pt_par in developer manual
	const double ptpar = ptmin + np/5.;

	const double arctan = std::atan((ptmax - ptmin)/ptpar);
	const double xpt = ran.flat();
	const double pt = ptmin + ptparstd::tan(xptarctan);
	const double cosine = std::cos(xpt*arctan);
	weight_ = ptptpararctan/(cosinecosine);
	return pt;
	}

	double PhaseSpacePoint::gen_soft_pt(int np, double max_pt, HEJ::RNG & ran) {
	constexpr double ptpar = 4.;

	const double r = ran.flat();
	const double pt = max_pt + ptpar/np*std::log(r);
	weight_ = ptptpar/(np*r);
	return pt;
	}

	double PhaseSpacePoint::gen_parton_pt(
	int count, JetParameters const & jet_param, double max_pt, double y,
	HEJ::RNG & ran
	) {
	constexpr double p_small_pt = 0.02;

	if(! jet_param.peak_pt) {
	return gen_hard_pt(count, jet_param.min_pt, max_pt, y, ran);
	}
	const double r = ran.flat();
	if(r > p_small_pt) {
	weight_ /= 1. - p_small_pt;
	return gen_hard_pt(count, *jet_param.peak_pt, max_pt, y, ran);
	}
	weight_ /= p_small_pt;
	const double pt = gen_soft_pt(count, *jet_param.peak_pt, ran);
	if(pt < jet_param.min_pt) {
	weight_=0.0;
	status_ = Status::not_enough_jets;
	return jet_param.min_pt;
	}
	return pt;
	}

	std::vector<fastjet::PseudoJet> PhaseSpacePoint::gen_LO_partons(
	int np, bool is_pure_jets,
	JetParameters const & jet_param,
	double max_pt,
	HEJ::RNG & ran
	){
	if (np<2) throw std::invalid_argument{"Not enough partons in gen_LO_partons"};

	weight_ /= std::pow(16.*std::pow(M_PI,3),np);
	weight_ /= std::tgamma(np+1); //remove rapidity ordering
	std::vector<fastjet::PseudoJet> partons;
	partons.reserve(np);
	for(int i = 0; i < np; ++i){
	const double y = -jet_param.max_y + 2jet_param.max_yran.flat();
	weight_ = 2jet_param.max_y;

	const bool is_last_parton = i+1 == np;
	if(is_pure_jets && is_last_parton) {
	constexpr double parton_mass_sq = 0.;
	partons.emplace_back(gen_last_momentum(partons, parton_mass_sq, y));
	break;
	}

	const double phi = 2M_PIran.flat();
	weight_ = 2.0M_PI;

	const double pt = gen_parton_pt(np, jet_param, max_pt, y, ran);
	if(weight_ == 0.0) return {};

	partons.emplace_back(fastjet::PtYPhiM(pt, y, phi));
	assert(jet_param.min_pt <= partons[i].pt());
	assert(partons[i].pt() <= max_pt+1e-5);
	}
	// Need to check that at LO, the number of jets = number of partons;
	fastjet::ClusterSequence cs(partons, jet_param.def);
	auto cluster_jets=cs.inclusive_jets(jet_param.min_pt);
	if (cluster_jets.size()!=unsigned(np)){
	weight_=0.0;
	status_ = Status::not_enough_jets;
	return {};
	}

	std::sort(begin(partons), end(partons), HEJ::rapidity_less{});

	return partons;
	}

	HEJ::Particle PhaseSpacePoint::gen_boson(
	HEJ::ParticleID bosonid, double mass, double width,
	+ Process const & proc,
	+ std::optional<subleading::Channels> const channel,
	HEJ::RNG & ran
	){
	// Usual phase space measure for single particle,
	// see eq:single_particle_phase_space in developer manual
	weight_ /= 16.*std::pow(M_PI, 3);

	const double y = (bosonid == HEJ::pid::Higgs)?
	- gen_Higgs_rapidity(ran):
	+ gen_Higgs_rapidity(proc, channel, ran):
	gen_V_boson_rapidity(ran);

	// off-shell sampling, see eq:breit-wigner-sampling in developer manual
	const double r1 = ran.flat();
	const double s_boson = mass*(
	mass + widthstd::tan(M_PI/2.r1 + (r1-1.)*std::atan(mass/width))
	);
	if(bosonid != HEJ::pid::Higgs){
	// two-particle phase space,
	// compare eq:two_particle_phase_space and eq:one_particle_phase_space
	// in developer manual
	weight_/=M_PIM_PI16.;
	// Jacobian, see eq:breit-wigner-sampling_jacobian in developer manual
	weight_= masswidth( M_PI+2.std::atan(mass/width) )
	/ ( 1. + std::cos( M_PIr1 + 2.(r1-1.)*std::atan(mass/width) ) );
	}

	return {
	bosonid,
	gen_last_momentum(outgoing_, s_boson, y),
	{}
	};
	}

	double PhaseSpacePoint::gen_Higgs_rapidity(
	+ Process const & proc,
	+ std::optional<subleading::Channels> const channel,
	HEJ::RNG & ran
	) {
	constexpr double STDDEV_Y_H = 1.6;
	+ if(channel && *channel == subleading::uno) {
	+ assert(outgoing().size() >= 3);
	+ if(proc.incoming[0] == HEJ::pid::gluon) {
	+ // backward uno not possible
	+ // Higgs has to be before the second most forward parton
	+ assert(proc.incoming[1] != HEJ::pid::gluon);
	+ return random_normal_trunc(
	+ STDDEV_Y_H,
	+ ran,
	+ std::numeric_limits<double>::lowest(),
	+ outgoing_[outgoing().size() - 2].rapidity()
	+ );
	+ }
	+ if(proc.incoming[1] == HEJ::pid::gluon) {
	+ // forward uno not possible
	+ // Higgs has to be after the second most backward parton
	+ assert(proc.incoming[0] != HEJ::pid::gluon);
	+ return random_normal_trunc(
	+ STDDEV_Y_H,
	+ ran,
	+ outgoing_[1].rapidity(),
	+ std::numeric_limits<double>::max()
	+ );
	+ }
	+ }
	return random_normal(STDDEV_Y_H, ran);
	}

	double PhaseSpacePoint::gen_V_boson_rapidity(
	HEJ::RNG & ran
	){
	// two Gaussians around (+/-)2.6 of std width ~1.8
	const int backward = int (2*ran.flat()); //0:forward 1:backward
	// This is not an integral over two distributions, but a random choice of
	// which option to take, each one representing the full integral.
	// So the weight of the integral should not be multiplied by 2
	constexpr double STDDEV_Y_V = 1.8;
	const double y = random_normal(STDDEV_Y_V, ran);
	return y + (1.-2.backward)2.6; // add or subtract 2.6
	}

	namespace {
	/// partons are ordered: even = anti, 0 = gluon
	- HEJ::ParticleID index_to_pid(size_t i){
	+ constexpr HEJ::ParticleID index_to_pid(size_t i){
	if(!i) return HEJ::pid::gluon;
	return static_cast<HEJ::ParticleID>( i%2 ? (i+1)/2 : -i/2 );
	}

	/// partons are ordered: even = anti, 0 = gluon
	- size_t pid_to_index(HEJ::ParticleID id){
	+ constexpr size_t pid_to_index(HEJ::ParticleID id){
	if(id==HEJ::pid::gluon) return 0;
	return id>0 ? id2-1 : std::abs(id)2;
	}

	+ constexpr PhaseSpacePoint::part_mask GLUON = 1u << pid_to_index(HEJ::pid::gluon);
	+ constexpr PhaseSpacePoint::part_mask ALL = ~0;
	+
	PhaseSpacePoint::part_mask init_allowed(HEJ::ParticleID const id){
	if(std::abs(id) == HEJ::pid::proton)
	- return ~0;
	+ return ALL;
	PhaseSpacePoint::part_mask out{0};
	if(HEJ::is_parton(id))
	out[pid_to_index(id)] = true;
	return out;
	}

	/// decides which "index" (see index_to_pid) are allowed for process
	PhaseSpacePoint::part_mask allowed_quarks(HEJ::ParticleID const boson){
	if(std::abs(boson) != HEJ::pid::Wp){
	- return ~1; // not a gluon
	+ return ~GLUON;
	}
	// special case W:
	// Wp: anti-down or up-type quark, no b/t
	// Wm: down or anti-up-type quark, no b/t
	return boson>0?0b00011001100 // NOLINT(readability-magic-numbers)
	:0b00100110010; // NOLINT(readability-magic-numbers)
	}
	} // namespace

	std::array<PhaseSpacePoint::part_mask,2> PhaseSpacePoint::incoming_AWZ(
	- Process const & proc, Subleading const subl_channels,
	+ Process const & proc,
	std::array<part_mask,2> allowed_partons,
	HEJ::RNG & ran
	){
	assert(proc.boson);
	auto couple_parton = allowed_quarks(*proc.boson);
	- // eqqbar possible if one incoming is a gluon
	- if(proc.njets >= 3 && subl_channels[subleading::eqqbar]){
	- couple_parton.set(pid_to_index(HEJ::ParticleID::gluon));
	- }
	if( // coupling possible through input
	allowed_partons[0] == (couple_parton&allowed_partons[0])
	\|\| allowed_partons[1] == (couple_parton&allowed_partons[1])
	- // cqqbar possible
	- \|\| (proc.njets >= 4 && subl_channels[subleading::cqqbar])
	){
	return allowed_partons;
	}
	// only first can couple
	if( (allowed_partons[0]&couple_parton).any()
	&&(allowed_partons[1]&couple_parton).none()
	){
	return {allowed_partons[0]&couple_parton, allowed_partons[1]};
	}
	// only second can couple
	if( (allowed_partons[0]&couple_parton).none()
	&& (allowed_partons[1]&couple_parton).any()
	){
	return {allowed_partons[0], allowed_partons[1]&couple_parton};
	}
	// both can couple
	if( (allowed_partons[0]&couple_parton).any()
	&& (allowed_partons[1]&couple_parton).any()
	){
	double rnd = ran.flat();
	weight_*=3.;
	if(rnd<1./3.){
	return {
	allowed_partons[0] & couple_parton,
	allowed_partons[1] & ~couple_parton
	};
	}
	if(rnd<2./3.){
	return {
	allowed_partons[0] & ~couple_parton,
	allowed_partons[1] & couple_parton
	};
	}
	return {
	allowed_partons[0] & couple_parton,
	allowed_partons[1] & couple_parton
	};
	}
	throw std::invalid_argument{"Incoming state not allowed."};
	}

	std::array<PhaseSpacePoint::part_mask,2> PhaseSpacePoint::incoming_eqqbar(
	std::array<part_mask,2> allowed_partons, HEJ::RNG & ran
	){
	auto const gluon_idx = pid_to_index(HEJ::pid::gluon);
	auto & first_beam = allowed_partons[0];
	auto & second_beam = allowed_partons[1];
	if(first_beam[gluon_idx] && !second_beam[gluon_idx]){
	first_beam.reset();
	first_beam.set(gluon_idx);
	return allowed_partons;
	}
	if(!first_beam[gluon_idx] && second_beam[gluon_idx]) {
	second_beam.reset();
	second_beam.set(gluon_idx);
	return allowed_partons;
	}
	if(first_beam[gluon_idx] && second_beam[gluon_idx]) {
	// both beams can be gluons
	// if one can't be a quark everything is good
	auto first_quarks = first_beam;
	first_quarks.reset(gluon_idx);
	auto second_quarks = second_beam;
	second_quarks.reset(gluon_idx);
	if(first_quarks.none() \|\| second_quarks.none()){
	return allowed_partons;
	}
	// else choose one to be a gluon
	double rnd = ran.flat();
	weight_*=3.;
	if(rnd<1./3.){
	allowed_partons[0].reset();
	allowed_partons[0].set(gluon_idx);
	allowed_partons[1].reset(gluon_idx);
	} else if(rnd<2./3.){
	allowed_partons[1].reset();
	allowed_partons[1].set(gluon_idx);
	allowed_partons[0].reset(gluon_idx);
	} else {
	allowed_partons[0].reset();
	allowed_partons[0].set(gluon_idx);
	allowed_partons[1].reset();
	allowed_partons[1].set(gluon_idx);
	}
	return allowed_partons;
	}
	throw std::invalid_argument{
	"Incoming state not allowed for pure extremal qqbar."};
	}

	std::array<PhaseSpacePoint::part_mask,2> PhaseSpacePoint::incoming_uno(
	std::array<part_mask,2> allowed_partons, HEJ::RNG & ran
	){
	auto const gluon_idx = pid_to_index(HEJ::pid::gluon);
	auto & first_beam = allowed_partons[0];
	+ auto & second_beam = allowed_partons[1];
	+ // cannot have Higgs on same side as uno
	+ if(outgoing_[0].type == HEJ::pid::Higgs \|\| outgoing_[1].type == HEJ::pid::Higgs) {
	+ assert(outgoing().size() >= 4);
	+ second_beam.reset(gluon_idx);
	+ assert(second_beam.any());
	+ } else if(
	+ outgoing_.back().type == HEJ::pid::Higgs
	+ \|\| outgoing_[outgoing_.size() - 2].type == HEJ::pid::Higgs
	+ ) {
	+ assert(outgoing().size() >= 4);
	+ first_beam.reset(gluon_idx);
	+ assert(first_beam.any());
	+ }
	auto first_quarks = first_beam;
	first_quarks.reset(gluon_idx);
	- auto & second_beam = allowed_partons[1];
	auto second_quarks = second_beam;
	second_quarks.reset(gluon_idx);
	if(first_quarks.any() && second_quarks.none()){
	first_beam.reset(gluon_idx);
	return allowed_partons;
	}
	if(first_quarks.none() && second_quarks.any()) {
	second_beam.reset(gluon_idx);
	return allowed_partons;
	}
	if(first_quarks.any() && second_quarks.any()) {
	// both beams can be quarks
	// if one can't be gluon everything is good
	if(!first_beam[gluon_idx] \|\| !second_beam[gluon_idx]){
	return allowed_partons;
	}
	// else choose one to be a quark
	double rnd = ran.flat();
	weight_*=3.;
	if(rnd<1./3.){
	allowed_partons[0].reset(gluon_idx);
	allowed_partons[1].reset();
	allowed_partons[1].set(gluon_idx);
	} else if(rnd<2./3.){
	allowed_partons[1].reset(gluon_idx);
	allowed_partons[0].reset();
	allowed_partons[0].set(gluon_idx);
	} else {
	allowed_partons[0].reset(gluon_idx);
	allowed_partons[1].reset(gluon_idx);
	}
	return allowed_partons;
	}
	throw std::invalid_argument{
	"Incoming state not allowed for pure unordered."};
	}

	/**
	* @brief Returns list of all allowed initial states partons
	*
	* checks which partons are allowed as initial state:
	* 1. only allow what is given in the Runcard (p -> all)
	* 2. A/W/Z require something to couple to
	* a) no qqbar => no incoming gluon
	* b) 2j => no incoming gluon
	* c) >3j => can couple OR is gluon => 2 gluons become qqbar later
	* 3. pure eqqbar requires at least one gluon
	* 4. pure uno requires at least one quark
	*/
	std::array<PhaseSpacePoint::part_mask,2> PhaseSpacePoint::allowed_incoming(
	Process const & proc,
	- double const subl_chance, Subleading const subl_channels,
	+ std::optional<subleading::Channels> channel,
	HEJ::RNG & ran
	){
	// all possible incoming states
	std::array<part_mask,2> allowed_partons{
	init_allowed(proc.incoming[0]),
	init_allowed(proc.incoming[1])
	};
	- // special case A/W/Z
	- if(proc.boson && is_AWZ_proccess(proc)){
	- allowed_partons = incoming_AWZ(proc, subl_channels, allowed_partons, ran);
	+ // special case: A/W/Z without qqbar
	+ if(
	+ is_AWZ_proccess(proc)
	+ && (!channel \|\| *channel == subleading::unordered)
	+ ) {
	+ return incoming_AWZ(proc, allowed_partons, ran);
	}
	- // special case: pure subleading
	- if(subl_chance!=1.){
	+ if(!channel) return allowed_partons;
	+ switch(*channel) {
	+ case subleading::central_qqbar:
	return allowed_partons;
	- }
	- auto other_channels = subl_channels;
	- // pure eqqbar
	- other_channels.reset(subleading::eqqbar);
	- if(other_channels.none()){
	+ case subleading::extremal_qqbar:
	return incoming_eqqbar(allowed_partons, ran);
	- }
	- other_channels = subl_channels;
	- // pure uno
	- other_channels.reset(subleading::uno);
	- if(other_channels.none()){
	+ case subleading::unordered:
	return incoming_uno(allowed_partons, ran);
	- }
	- return allowed_partons;
	+ default:;
	+ };
	+ throw std::logic_error{"enum value not covered"};
	}

	-
	void PhaseSpacePoint::reconstruct_incoming(
	Process const & proc,
	- double const subl_chance, Subleading const subl_channels,
	+ std::optional<subleading::Channels> const channel,
	HEJ::PDF & pdf, double E_beam,
	double uf,
	HEJ::RNG & ran
	){
	std::tie(incoming_[0].p, incoming_[1].p) = incoming_momenta(outgoing_);
	// calculate xa, xb
	const double sqrts=2*E_beam;
	const double xa=(incoming_[0].E()-incoming_[0].pz())/sqrts;
	const double xb=(incoming_[1].E()+incoming_[1].pz())/sqrts;
	// abort if phase space point is outside of collider energy reach
	if (xa>1. \|\| xb>1.){
	weight_=0;
	status_ = Status::too_much_energy;
	return;
	}
	auto const & ids = proc.incoming;
	std::array<part_mask,2> allowed_partons
	- = allowed_incoming(proc, subl_chance, subl_channels, ran);
	+ = allowed_incoming(proc, channel, ran);
	for(size_t i = 0; i < 2; ++i){
	if(ids[i] == HEJ::pid::proton \|\| ids[i] == HEJ::pid::p_bar){
	// pick ids according to pdfs
	incoming_[i].type =
	generate_incoming_id(i, i?xb:xa, uf, pdf, allowed_partons[i], ran);
	} else {
	assert(allowed_partons[i][pid_to_index(ids[i])]);
	incoming_[i].type = ids[i];
	}
	}
	assert(momentum_conserved(1e-7));
	}

	HEJ::ParticleID PhaseSpacePoint::generate_incoming_id(
	size_t const beam_idx, double const x, double const uf,
	HEJ::PDF & pdf, part_mask allowed_partons, HEJ::RNG & ran
	){
	std::array<double,NUM_PARTONS> pdf_wt{};
	pdf_wt[0] = allowed_partons[0]?
	std::fabs(pdf.pdfpt(beam_idx,x,uf,HEJ::pid::gluon)):0.;
	double pdftot = pdf_wt[0];
	for(size_t i = 1; i < pdf_wt.size(); ++i){
	pdf_wt[i] = allowed_partons[i]?
	4./9.*std::fabs(pdf.pdfpt(beam_idx,x,uf,index_to_pid(i))):0;
	pdftot += pdf_wt[i];
	}
	const double r1 = pdftot * ran.flat();
	double sum = 0;
	for(size_t i=0; i < pdf_wt.size(); ++i){
	if (r1 < (sum+=pdf_wt[i])){
	weight_*= pdftot/pdf_wt[i];
	return index_to_pid(i);
	}
	}
	std::cerr << "Error in choosing incoming parton: "<<x<<" "<<uf<<" "
	<<sum<<" "<<pdftot<<" "<<r1<<std::endl;
	throw std::logic_error{"Failed to choose parton flavour"};
	}

	void PhaseSpacePoint::couple_boson(
	HEJ::ParticleID const boson, HEJ::RNG & ran
	){
	if(std::abs(boson) != HEJ::pid::Wp) return; // only matters for W
	/// @TODO this could be use to sanity check gamma and Z

	// find all possible quarks
	std::vector<PartonIterator> allowed_parts;
	for(auto part_it=begin_partons(); part_it!=end_partons(); ++part_it){
	// Wp -> up OR anti-down, Wm -> anti-up OR down, no bottom
	if ( can_couple_to_W(*part_it, boson) )
	allowed_parts.push_back(part_it);
	}
	if(allowed_parts.empty()){
	throw std::logic_error{"Found no parton for coupling with boson"};
	}

	// select one and flip it
	size_t idx = 0;
	if(allowed_parts.size() > 1){
	/// @TODO more efficient sampling
	/// old code: probability[i] = exp(parton[i].y - W.y)
	idx = std::floor(ran.flat()*allowed_parts.size());
	weight_ *= allowed_parts.size();
	}
	const int W_charge = boson>0?1:-1;
	allowed_parts[idx]->type =
	static_cast<HEJ::ParticleID>( allowed_parts[idx]->type - W_charge );
	}

	double PhaseSpacePoint::random_normal( double stddev, HEJ::RNG & ran ){
	const double r1 = ran.flat();
	const double r2 = ran.flat();
	const double lninvr1 = -std::log(r1);
	const double result = stddevstd::sqrt(2.lninvr1)std::cos(2.M_PI*r2);
	weight_ = exp(resultresult/(2stddevstddev))std::sqrt(2.M_PI)*stddev;
	return result;
	}

	+ double PhaseSpacePoint::random_normal_trunc(
	+ const double stddev,
	+ HEJ::RNG & ran,
	+ const double min,
	+ const double max
	+ ) {
	+ double result;
	+ std::uint64_t trials = 0;
	+ do {
	+ ++trials;
	+ const double r1 = ran.flat();
	+ const double r2 = ran.flat();
	+ const double lninvr1 = -std::log(r1);
	+ result = stddevstd::sqrt(2.lninvr1)std::cos(2.M_PI*r2);
	+ } while(result < min \|\| result > max);
	+ weight_ = exp(resultresult/(2stddevstddev))std::sqrt(2.M_PI)*stddev / trials;
	+ return result;
	+ }
	+
	bool PhaseSpacePoint::momentum_conserved(double ep) const{
	fastjet::PseudoJet diff;
	for(auto const & in: incoming()) diff += in.p;
	for(auto const & out: outgoing()) diff -= out.p;
	return HEJ::nearby_ep(diff, fastjet::PseudoJet{}, ep);
	}

	+ std::optional<subleading::Channels> PhaseSpacePoint::select_channel(
	+ Subleading const subl_channels,
	+ double const chance,
	+ HEJ::RNG & ran
	+ ) {
	+ const double r = ran.flat();
	+ if(r > chance) {
	+ weight_ /= 1 - chance;
	+ return {};
	+ }
	+ // pick a random subleading channel (flat)
	+ const std::size_t num_channels = subl_channels.count();
	+ weight_ *= num_channels / chance;
	+ std::size_t channel_idx = r / chance * num_channels;
	+ for(
	+ unsigned channel = subleading::first;
	+ channel <= subleading::last;
	+ ++channel
	+ ) {
	+ if(subl_channels.test(channel)) {
	+ if(channel_idx == 0) {
	+ return {static_cast<subleading::Channels>(channel)};
	+ } else {
	+ --channel_idx;
	+ }
	+ }
	+ }
	+ throw std::logic_error{"unreachable"};
	+ }
	+
	} // namespace HEJFOG
	diff --git a/FixedOrderGen/t/W_2j_classify.cc b/FixedOrderGen/t/W_2j_classify.cc
	index 7b7ee17..2e0c264 100644
	--- a/FixedOrderGen/t/W_2j_classify.cc
	+++ b/FixedOrderGen/t/W_2j_classify.cc
	@@ -1,163 +1,163 @@
	/**
	* \brief check that the PSP generates only "valid" W + 2 jets events
	*
	* \authors The HEJ collaboration (see AUTHORS for details)
	* \date 2019-2020
	* \copyright GPLv2 or later
	*/

	#include <cstdlib>
	#include <iostream>
	#include <string>
	#include <vector>

	#include "fastjet/JetDefinition.hh"

	#include "HEJ/EWConstants.hh"
	#include "HEJ/exceptions.hh"
	#include "HEJ/Mixmax.hh"
	#include "HEJ/Particle.hh"
	#include "HEJ/PDF.hh"
	#include "HEJ/PDG_codes.hh"

	#include "Decay.hh"
	#include "JetParameters.hh"
	#include "PhaseSpacePoint.hh"
	#include "Process.hh"
	#include "Status.hh"
	#include "Subleading.hh"

	namespace {
	using namespace HEJFOG;
	using namespace HEJ;

	void print_psp(PhaseSpacePoint const & psp){
	std::cerr << "Process:\n"
	<< psp.incoming()[0].type << " + "<< psp.incoming()[1].type << " -> ";
	for(auto const & out: psp.outgoing()){
	std::cerr << out.type << " ";
	}
	std::cerr << "\n";
	}

	void bail_out(PhaseSpacePoint const & psp, std::string msg){
	print_psp(psp);
	throw std::logic_error{msg};
	}

	bool is_up_type(Particle const & part){
	return HEJ::is_anyquark(part) && !(std::abs(part.type)%2);
	}
	bool is_down_type(Particle const & part){
	return HEJ::is_anyquark(part) && std::abs(part.type)%2;
	}

	bool check_W2j(PhaseSpacePoint const & psp, ParticleID const W_type){
	bool found_quark = false;
	bool found_anti = false;
	std::vector<Particle> out_partons;
	std::vector<Particle> Wp;
	for(auto const & p: psp.outgoing()){
	if(p.type == W_type) Wp.push_back(p);
	else if(is_parton(p)) out_partons.push_back(p);
	else bail_out(psp, "Found particle with is not "
	+std::to_string(int(W_type))+" or parton");
	}
	if(Wp.size() != 1 \|\| out_partons.size() != 2){
	bail_out(psp, "Found wrong number of outgoing partons");
	}
	for(std::size_t j=0; j<2; ++j){
	auto const & in = psp.incoming()[j];
	auto const & out = out_partons[j];
	if(is_quark(in) \|\| is_antiquark(in)) {
	found_quark = true;
	if(in.type != out.type) { // switch in quark type -> Wp couples to it
	if(found_anti){ // already found qq for coupling to W
	bail_out(psp, "Found second up/down pair");
	} else if(std::abs(in.type)>4 \|\| std::abs(out.type)>4){
	bail_out(psp, "Found bottom/top pair");
	}
	found_anti = true;
	if( is_up_type(in)) { // "up" in
	if(W_type > 0){
	// -> only allowed u -> Wp + d
	if(in.type < 0 \|\| is_up_type(out) \|\| out.type < 0)
	bail_out(psp, "u -/> Wp + d");

	} else {
	// -> only allowed ux -> Wm + dx
	if(in.type > 0 \|\| is_up_type(out) \|\| out.type > 0)
	bail_out(psp, "ux -/> Wm + dx");
	}
	} else { // "down" in
	if(W_type > 0){
	// -> only allowed dx -> Wp + ux
	if(in.type > 0 \|\| is_down_type(out) \|\| out.type > 0)
	bail_out(psp, "dx -/> Wp + ux");
	} else {
	// -> only allowed d -> Wm + u
	if(in.type < 0 \|\| is_down_type(out) \|\| out.type < 0)
	bail_out(psp, "d -/> Wm + u");
	}
	}
	}
	}
	}
	if(!found_quark) {
	bail_out(psp, "Found no initial quarks");
	} else if(!found_anti){
	bail_out(psp, "Found no up/down pair");
	}
	return true;
	}
	}

	int main(){
	constexpr std::size_t n_psp_base = 1337;
	const JetParameters jet_para{
	fastjet::JetDefinition(fastjet::JetAlgorithm::antikt_algorithm, 0.4), 30, 5, 30};
	PDF pdf(11000, pid::proton, pid::proton);
	constexpr double E_cms = 13000.;
	- constexpr double subl_chance = 0.5;
	- const Subleading subl_channels = subleading::ALL;
	+ constexpr double subl_chance = 0.0;
	+ const Subleading subl_channels = subleading::NONE;
	const ParticlesDecayMap boson_decays{
	{pid::Wp, {Decay{ {pid::e_bar, pid::nu_e}, 1.} }},
	{pid::Wm, {Decay{ {pid::e, pid::nu_e_bar}, 1.} }}
	};
	constexpr EWConstants ew_constants{246.2196508, {80.385, 2.085},
	{91.187, 2.495},
	{125, 0.004165} };
	HEJ::Mixmax ran{};

	// Wp2j
	Process proc {{pid::proton,pid::proton}, 2, pid::Wp, {}};
	std::size_t n_psp = n_psp_base;
	for( std::size_t i = 0; i<n_psp; ++i){
	const PhaseSpacePoint psp{proc,jet_para,pdf,E_cms, subl_chance,subl_channels,
	boson_decays, ew_constants, ran};
	if(psp.status()==Status::good){
	check_W2j(psp, *proc.boson);
	} else { // bad process -> try again
	++n_psp;
	}
	}
	std::cout << "Wp+2j: Took " << n_psp << " to generate "
	<< n_psp_base << " successfully PSP (" << 1.*n_psp/n_psp_base << " trials/PSP)" << std::endl;
	// Wm2j
	proc = Process{{pid::proton,pid::proton}, 2, pid::Wm, {}};
	n_psp = n_psp_base;
	for( std::size_t i = 0; i<n_psp; ++i){
	const PhaseSpacePoint psp{proc,jet_para,pdf,E_cms, subl_chance,subl_channels,
	boson_decays, ew_constants, ran};
	if(psp.status()==Status::good){
	check_W2j(psp, *proc.boson);
	} else { // bad process -> try again
	++n_psp;
	}
	}
	std::cout << "Wm+2j: Took " << n_psp << " to generate "
	<< n_psp_base << " successfully PSP (" << 1.*n_psp/n_psp_base << " trials/PSP)" << std::endl;

	std::cout << "All processes passed." << std::endl;
	return EXIT_SUCCESS;
	}
	diff --git a/FixedOrderGen/t/W_nj_classify.cc b/FixedOrderGen/t/W_nj_classify.cc
	index 44437d8..c6576db 100644
	--- a/FixedOrderGen/t/W_nj_classify.cc
	+++ b/FixedOrderGen/t/W_nj_classify.cc
	@@ -1,226 +1,227 @@
	/**
	* \brief check that the PSP generates the all W+jet subleading processes
	*
	* \authors The HEJ collaboration (see AUTHORS for details)
	* \date 2019-2020
	* \copyright GPLv2 or later
	*/

	#include <algorithm>
	#include <cmath>
	#include <cstdlib>
	#include <iomanip>
	#include <iostream>
	#include <string>
	#include <unordered_map>
	#include <vector>

	#include "HEJ/Event.hh"
	#include "HEJ/event_types.hh"
	#include "HEJ/EWConstants.hh"
	#include "HEJ/exceptions.hh"
	#include "HEJ/Mixmax.hh"
	#include "HEJ/PDF.hh"
	#include "HEJ/PDG_codes.hh"

	#include "fastjet/JetDefinition.hh"

	#include "Decay.hh"
	#include "JetParameters.hh"
	#include "PhaseSpacePoint.hh"
	#include "Process.hh"
	#include "Status.hh"
	#include "Subleading.hh"

	namespace {
	using namespace HEJFOG;
	using namespace HEJ;

	void print_psp(PhaseSpacePoint const & psp){
	std::cerr << "Process:\n"
	<< psp.incoming()[0].type << " + "<< psp.incoming()[1].type << " -> ";
	for(auto const & out: psp.outgoing()){
	std::cerr << out.type << " ";
	}
	std::cerr << "\n";
	}
	void bail_out(PhaseSpacePoint const & psp, std::string msg){
	print_psp(psp);
	throw std::logic_error{msg};
	}

	#if !defined(__clang__) && defined(__GNUC__) && (__GNUC__ < 6)
	// gcc version < 6 explicitly needs hash function for enum
	// see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60970
	using type_map = std::unordered_map<event_type::EventType, std::size_t, std::hash<std::size_t>>;
	#else
	using type_map = std::unordered_map<event_type::EventType, std::size_t>;
	#endif
	}

	int main(){
	constexpr std::size_t n_psp_base = 10375;
	const JetParameters jet_para{
	fastjet::JetDefinition(fastjet::JetAlgorithm::antikt_algorithm, 0.4), 30, 5, 30};
	PDF pdf(11000, pid::proton, pid::proton);
	constexpr double E_cms = 13000.;
	constexpr double subl_chance = 0.8;
	const ParticlesDecayMap boson_decays{
	{pid::Wp, {Decay{ {pid::e_bar, pid::nu_e}, 1.} }},
	{pid::Wm, {Decay{ {pid::e, pid::nu_e_bar}, 1.} }}
	};
	constexpr EWConstants ew_constants{246.2196508, {80.385, 2.085},
	{91.187, 2.495},
	{125, 0.004165}
	};
	HEJ::Mixmax ran{};

	Subleading subl_channels = subleading::ALL;
	+ subl_channels.reset(subleading::cqqbar);
	std::vector<event_type::EventType> allowed_types{event_type::FKL,
	event_type::unob, event_type::unof, event_type::qqbar_exb, event_type::qqbar_exf};

	std::cout << "Wp3j" << std::endl;
	// Wp3j
	Process proc {{pid::proton,pid::proton}, 3, pid::Wp, {}};
	std::size_t n_psp = n_psp_base;

	type_map type_counter;

	for( std::size_t i = 0; i<n_psp; ++i){
	const PhaseSpacePoint psp{proc,jet_para,pdf,E_cms, subl_chance,subl_channels,
	boson_decays, ew_constants, ran};
	if(psp.status()==Status::good){
	const Event ev{ to_EventData(psp).cluster(jet_para.def, jet_para.min_pt) };
	++type_counter[ev.type()];
	if( std::find(allowed_types.cbegin(), allowed_types.cend(), ev.type())
	== allowed_types.cend()) {
	bail_out(psp, "Found not allowed event of type " + name(ev.type()) );
	}
	} else { // bad process -> try again
	++n_psp;
	}
	}
	std::cout << "Wp+3j: Took " << n_psp << " to generate "
	<< n_psp_base << " successfully PSP (" << 1.*n_psp/n_psp_base << " trials/PSP)" << std::endl;
	std::cout << "States by classification:\n";
	for(auto const & entry: type_counter){
	const double fraction = static_cast<double>(entry.second)/n_psp_base;
	const int percent = std::round(100*fraction);
	std::cout << std::left << std::setw(25)
	<< (name(entry.first) + std::string(":"))
	<< entry.second << " (" << percent << "%)\n";

	}
	for(auto const & t: allowed_types){
	if(type_counter[t] < 0.05 * n_psp_base){
	std::cerr << "Less than 5% of the events are of type " << name(t) << std::endl;
	return EXIT_FAILURE;
	}
	}

	// Wm3j - only uno
	proc = Process{{pid::proton,pid::proton}, 3, pid::Wm, {}};
	n_psp = n_psp_base;

	subl_channels.reset();
	subl_channels.set(subleading::uno);
	allowed_types = {event_type::FKL, event_type::unob, event_type::unof};
	type_counter.clear();

	for( std::size_t i = 0; i<n_psp; ++i){
	const PhaseSpacePoint psp{proc,jet_para,pdf,E_cms, subl_chance,subl_channels,
	boson_decays, ew_constants, ran};
	if(psp.status()==Status::good){
	const Event ev{ to_EventData(psp).cluster(jet_para.def, jet_para.min_pt) };
	++type_counter[ev.type()];
	if( std::find(allowed_types.cbegin(), allowed_types.cend(), ev.type())
	== allowed_types.cend()) {
	bail_out(psp, "Found not allowed event of type " + name(ev.type()) );
	}
	} else { // bad process -> try again
	++n_psp;
	}
	}
	std::cout << "Wm+3j (only uno): Took " << n_psp << " to generate "
	<< n_psp_base << " successfully PSP (" << 1.*n_psp/n_psp_base << " trials/PSP)" << std::endl;
	std::cout << "States by classification:\n";
	for(auto const & entry: type_counter){
	const double fraction = static_cast<double>(entry.second)/n_psp_base;
	const int percent = std::round(100*fraction);
	std::cout << std::left << std::setw(25)
	<< (name(entry.first) + std::string(":"))
	<< entry.second << " (" << percent << "%)\n";

	}
	for(auto const & t: allowed_types){
	if(type_counter[t] < 0.05 * n_psp_base){
	std::cerr << "Less than 5% of the events are of type " << name(t) << std::endl;
	return EXIT_FAILURE;
	}
	}

	// Wm4j
	proc = Process{{pid::proton,pid::proton}, 4, pid::Wm, {}};
	n_psp = n_psp_base;

	subl_channels.set();
	allowed_types = {event_type::FKL,
	event_type::unob, event_type::unof, event_type::qqbar_exb, event_type::qqbar_exf,
	event_type::qqbar_mid};
	type_counter.clear();
	std::array<type_map,3> wpos_counter; // position of the W boson (back, central, forward)

	for( std::size_t i = 0; i<n_psp; ++i){
	const PhaseSpacePoint psp{proc,jet_para,pdf,E_cms, subl_chance,subl_channels,
	boson_decays, ew_constants, ran};
	if(psp.status()==Status::good){
	const Event ev{ to_EventData(psp).cluster(jet_para.def, jet_para.min_pt)};
	++type_counter[ev.type()];
	if( std::find(allowed_types.cbegin(), allowed_types.cend(), ev.type())
	== allowed_types.cend()) {
	bail_out(psp, "Found not allowed event of type " + name(ev.type()) );
	}
	if(ev.outgoing().begin()->type==pid::Wm){
	++wpos_counter[0][ev.type()];
	} else if(ev.outgoing().rbegin()->type==pid::Wm){
	++wpos_counter[2][ev.type()];
	} else {
	++wpos_counter[1][ev.type()];
	}
	} else { // bad process -> try again
	++n_psp;
	}
	}
	std::cout << "Wm+4j: Took " << n_psp << " to generate "
	<< n_psp_base << " successfully PSP (" << 1.*n_psp/n_psp_base << " trials/PSP)" << std::endl;
	std::cout << "States by classification:\n";
	for(auto const & entry: type_counter){
	const double fraction = static_cast<double>(entry.second)/n_psp_base;
	const int percent = std::round(100*fraction);
	std::cout << std::left << std::setw(25)
	<< (name(entry.first) + std::string(":"))
	<< entry.second << " (" << percent << "%)\n";

	}
	for(auto const & t: allowed_types){
	if(type_counter[t] < 0.03 * n_psp_base){
	std::cerr << "Less than 3% of the events are of type " << name(t) << std::endl;
	return EXIT_FAILURE;
	}
	}
	std::cout << "Stats by Wpos:\n";
	for(std::size_t i=0; i<wpos_counter.size(); ++i){
	std::cout << "position " << i << std::endl;;
	for(auto const & t: allowed_types){
	std::cout << name(t) << " " << wpos_counter[i][t] << std::endl;
	if(wpos_counter[i][t] < 0.05 * type_counter[t]){
	std::cerr << "Less than 5% of the events are of type " << name(t)
	<< " with W at position " << i << std::endl;
	return EXIT_FAILURE;
	}
	}
	}

	std::cout << "All processes passed." << std::endl;
	return EXIT_SUCCESS;
	}
	diff --git a/FixedOrderGen/t/Z_2j_classify.cc b/FixedOrderGen/t/Z_2j_classify.cc
	index b428a0e..9600e53 100644
	--- a/FixedOrderGen/t/Z_2j_classify.cc
	+++ b/FixedOrderGen/t/Z_2j_classify.cc
	@@ -1,111 +1,111 @@
	/**
	* \brief check that the PSP generates only "valid" Z + 2 jets events
	*
	* \authors The HEJ collaboration (see AUTHORS for details)
	* \date 2019-2020
	* \copyright GPLv2 or later
	*/

	#include <cstdlib>
	#include <iostream>
	#include <string>
	#include <vector>

	#include "fastjet/JetDefinition.hh"

	#include "HEJ/EWConstants.hh"
	#include "HEJ/exceptions.hh"
	#include "HEJ/Mixmax.hh"
	#include "HEJ/Particle.hh"
	#include "HEJ/PDF.hh"
	#include "HEJ/PDG_codes.hh"

	#include "Decay.hh"
	#include "JetParameters.hh"
	#include "PhaseSpacePoint.hh"
	#include "Process.hh"
	#include "Status.hh"
	#include "Subleading.hh"

	namespace {
	using namespace HEJFOG;
	using namespace HEJ;

	void print_psp(PhaseSpacePoint const & psp){
	std::cerr << "Process:\n"
	<< psp.incoming()[0].type << " + "<< psp.incoming()[1].type << " -> ";
	for(auto const & out: psp.outgoing()){
	std::cerr << out.type << " ";
	}
	std::cerr << "\n";
	}

	void bail_out(PhaseSpacePoint const & psp, std::string msg){
	print_psp(psp);
	throw std::logic_error{msg};
	}

	bool check_Z2j(PhaseSpacePoint const & psp){
	bool found_quark = false;
	std::vector<Particle> out_partons;
	std::vector<Particle> Z;
	for(auto const & p: psp.outgoing()){
	if(p.type == pid::Z_photon_mix) Z.push_back(p);
	else if(is_parton(p)) out_partons.push_back(p);
	else bail_out(psp, "Found particle which is not Z or parton");
	}
	if(Z.size() != 1 \|\| out_partons.size() != 2){
	bail_out(psp, "Found wrong number of outgoing partons");
	}
	for(std::size_t j=0; j<2; ++j){
	auto const & in = psp.incoming()[j];
	auto const & out = out_partons[j];
	if(is_quark(in) \|\| is_antiquark(in)) {
	found_quark = true;
	if(in.type != out.type) {
	bail_out(psp, "Switch in quark type");
	}
	}
	}
	if(!found_quark) {
	bail_out(psp, "Found no initial quark");
	}
	return true;
	}
	}

	int main(){
	constexpr std::size_t n_psp_base = 1337;
	const JetParameters jet_para{
	fastjet::JetDefinition(fastjet::JetAlgorithm::antikt_algorithm, 0.4), 30, 5, 30};
	PDF pdf(11000, pid::proton, pid::proton);
	constexpr double E_cms = 13000.;
	- constexpr double subl_chance = 0.5;
	- const Subleading subl_channels = subleading::ALL;
	+ constexpr double subl_chance = 0.0;
	+ const Subleading subl_channels = subleading::NONE;
	const ParticlesDecayMap boson_decays{
	{pid::Wp, {Decay{ {pid::e_bar, pid::nu_e}, 1.} }},
	{pid::Wm, {Decay{ {pid::e, pid::nu_e_bar}, 1.} }}
	};
	constexpr EWConstants ew_constants{246.2196508, {80.385, 2.085},
	{91.187, 2.495},
	{125, 0.004165} };
	HEJ::Mixmax ran{};

	// Z2j
	Process proc {{pid::proton,pid::proton}, 2, pid::Z_photon_mix, {pid::e_bar,pid::e}};
	std::size_t n_psp = n_psp_base;
	for( std::size_t i = 0; i<n_psp; ++i){
	const PhaseSpacePoint psp{proc,jet_para,pdf,E_cms, subl_chance,subl_channels,
	boson_decays, ew_constants, ran};
	if(psp.status()==Status::good){
	check_Z2j(psp);
	} else { // bad process -> try again
	++n_psp;
	}
	}
	std::cout << "Z+2j: Took " << n_psp << " to generate "
	<< n_psp_base << " successfully PSP (" << 1.*n_psp/n_psp_base << " trials/PSP)" << std::endl;

	std::cout << "All processes passed." << std::endl;
	return EXIT_SUCCESS;
	}

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