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diff --git a/src/Event.cc b/src/Event.cc
index 1deddb2..c17e540 100644
--- a/src/Event.cc
+++ b/src/Event.cc
@@ -1,486 +1,488 @@
/**
* \authors Jeppe Andersen, Tuomas Hapola, Marian Heil, Andreas Maier, Jennifer Smillie
* \date 2019
* \copyright GPLv2 or later
*/
#include "HEJ/Event.hh"
#include <algorithm>
#include <assert.h>
#include <numeric>
#include <utility>
#include "LHEF/LHEF.h"
#include "fastjet/JetDefinition.hh"
#include "HEJ/Constants.hh"
#include "HEJ/exceptions.hh"
#include "HEJ/PDG_codes.hh"
namespace HEJ{
namespace{
constexpr int status_in = -1;
constexpr int status_decayed = 2;
constexpr int status_out = 1;
/// @name helper functions to determine event type
//@{
/**
* \brief check if final state valid for HEJ
*
* check if there is at most one photon, W, H, Z in the final state
* and all the rest are quarks or gluons
*/
bool final_state_ok(std::vector<Particle> const & outgoing){
bool has_AWZH_boson = false;
for(auto const & out: outgoing){
if(is_AWZH_boson(out.type)){
if(has_AWZH_boson) return false;
has_AWZH_boson = true;
}
else if(! is_parton(out.type)) return false;
}
return true;
}
template<class Iterator>
Iterator remove_AWZH(Iterator begin, Iterator end){
return std::remove_if(
begin, end, [](Particle const & p){return is_AWZH_boson(p);}
);
}
template<class Iterator>
bool valid_outgoing(Iterator begin, Iterator end){
return std::distance(begin, end) >= 2
&& std::is_sorted(begin, end, rapidity_less{})
&& std::count_if(
begin, end, [](Particle const & s){return is_AWZH_boson(s);}
) < 2;
}
/// @note that this changes the outgoing range!
template<class ConstIterator, class Iterator>
bool is_FKL(
ConstIterator begin_incoming, ConstIterator end_incoming,
Iterator begin_outgoing, Iterator end_outgoing
){
assert(std::distance(begin_incoming, end_incoming) == 2);
assert(std::distance(begin_outgoing, end_outgoing) >= 2);
// One photon, W, H, Z in the final state is allowed.
// Remove it for remaining tests,
end_outgoing = remove_AWZH(begin_outgoing, end_outgoing);
// Test if this is a standard FKL configuration.
return
(begin_incoming->type == begin_outgoing->type)
&& ((end_incoming-1)->type == (end_outgoing-1)->type)
&& std::all_of(
begin_outgoing + 1, end_outgoing - 1,
[](Particle const & p){ return p.type == pid::gluon; }
);
}
bool is_FKL(
std::array<Particle, 2> const & incoming,
std::vector<Particle> outgoing
){
assert(std::is_sorted(begin(incoming), end(incoming), pz_less{}));
assert(valid_outgoing(begin(outgoing), end(outgoing)));
return is_FKL(
begin(incoming), end(incoming),
begin(outgoing), end(outgoing)
);
}
bool has_2_jets(Event const & event){
return event.jets().size() >= 2;
}
/**
* \brief Checks whether event is unordered backwards
* @param ev Event
* @returns Is Event Unordered Backwards
*
* - Checks there is more than 3 constuents in the final state
* - Checks there is more than 3 jets
* - Checks the most backwards parton is a gluon
* - Checks the most forwards jet is not a gluon
* - Checks the rest of the event is FKL
* - Checks the second most backwards is not a different boson
* - Checks the unordered gluon actually forms a jet
*/
bool is_unordered_backward(Event const & ev){
auto const & in = ev.incoming();
auto const & out = ev.outgoing();
assert(std::is_sorted(begin(in), end(in), pz_less{}));
assert(valid_outgoing(begin(out), end(out)));
if(out.size() < 3) return false;
if(ev.jets().size() < 3) return false;
if(in.front().type == pid::gluon) return false;
if(out.front().type != pid::gluon) return false;
// When skipping the unordered emission
// the remainder should be a regular FKL event,
// except that the (new) first outgoing particle must not be a A,W,Z,H.
const auto FKL_begin = next(begin(out));
if(is_AWZH_boson(*FKL_begin)) return false;
if(!is_FKL(in, {FKL_begin, end(out)})) return false;
// check that the unordered gluon forms an extra jet
const auto jets = sorted_by_rapidity(ev.jets());
const auto indices = ev.particle_jet_indices({jets.front()});
return indices[0] >= 0 && indices[1] == -1;
}
/**
* \brief Checks for a forward unordered gluon emission
* @param ev Event
* @returns Is the event a forward unordered emission
*
* \see is_unordered_backward
*/
bool is_unordered_forward(Event const & ev){
auto const & in = ev.incoming();
auto const & out = ev.outgoing();
assert(std::is_sorted(begin(in), end(in), pz_less{}));
assert(valid_outgoing(begin(out), end(out)));
if(out.size() < 3) return false;
if(ev.jets().size() < 3) return false;
if(in.back().type == pid::gluon) return false;
if(out.back().type != pid::gluon) return false;
// When skipping the unordered emission
// the remainder should be a regular FKL event,
// except that the (new) last outgoing particle must not be a A,W,Z,H.
const auto FKL_end = prev(end(out));
if(is_AWZH_boson(*prev(FKL_end))) return false;
if(!is_FKL(in, {begin(out), FKL_end})) return false;
// check that the unordered gluon forms an extra jet
const auto jets = sorted_by_rapidity(ev.jets());
const auto indices = ev.particle_jet_indices({jets.back()});
return indices.back() >= 0 && indices[indices.size()-2] == -1;
}
using event_type::EventType;
EventType classify(Event const & ev){
if(! final_state_ok(ev.outgoing())) return EventType::bad_final_state;
if(! has_2_jets(ev)) return EventType::no_2_jets;
if(is_FKL(ev.incoming(), ev.outgoing())) return EventType::FKL;
if(is_unordered_backward(ev)){
return EventType::unordered_backward;
}
if(is_unordered_forward(ev)){
return EventType::unordered_forward;
}
return EventType::nonHEJ;
}
//@}
Particle extract_particle(LHEF::HEPEUP const & hepeup, int i){
const ParticleID id = static_cast<ParticleID>(hepeup.IDUP[i]);
const fastjet::PseudoJet momentum{
hepeup.PUP[i][0], hepeup.PUP[i][1],
hepeup.PUP[i][2], hepeup.PUP[i][3]
};
if(is_parton(id))
return Particle{ id, std::move(momentum), hepeup.ICOLUP[i] };
return Particle{ id, std::move(momentum), {} };
}
bool is_decay_product(std::pair<int, int> const & mothers){
if(mothers.first == 0) return false;
return mothers.second == 0 || mothers.first == mothers.second;
}
} // namespace anonymous
UnclusteredEvent::UnclusteredEvent(LHEF::HEPEUP const & hepeup):
central(EventParameters{
hepeup.scales.mur, hepeup.scales.muf, hepeup.weight()
})
{
size_t in_idx = 0;
for (int i = 0; i < hepeup.NUP; ++i) {
// skip decay products
// we will add them later on, but we have to ensure that
// the decayed particle is added before
if(is_decay_product(hepeup.MOTHUP[i])) continue;
auto particle = extract_particle(hepeup, i);
// needed to identify mother particles for decay products
particle.p.set_user_index(i+1);
if(hepeup.ISTUP[i] == status_in){
if(in_idx > incoming.size()) {
throw std::invalid_argument{
"Event has too many incoming particles"
};
}
incoming[in_idx++] = std::move(particle);
}
else outgoing.emplace_back(std::move(particle));
}
// add decay products
for (int i = 0; i < hepeup.NUP; ++i) {
if(!is_decay_product(hepeup.MOTHUP[i])) continue;
const int mother_id = hepeup.MOTHUP[i].first;
const auto mother = std::find_if(
begin(outgoing), end(outgoing),
[mother_id](Particle const & particle){
return particle.p.user_index() == mother_id;
}
);
if(mother == end(outgoing)){
throw std::invalid_argument{"invalid decay product parent"};
}
const int mother_idx = std::distance(begin(outgoing), mother);
assert(mother_idx >= 0);
decays[mother_idx].emplace_back(extract_particle(hepeup, i));
}
}
namespace {
int connect_incoming(Particle & part, int & colour, int & anti_colour){
// TODO something is wrong here
part.colour = std::make_pair(anti_colour, colour);
// gluon
if(part.type == pid::gluon) {
return 0;
}
// q
if(part.type > 0){
- part.colour->second=0;
- anti_colour*=-1;
+ part.colour->second = 0;
+ colour*=-1;
return -1;
}
// qx
part.colour->first = 0;
- colour*=-1;
+ anti_colour*=-1;
return +1;
}
}
void UnclusteredEvent::generate_colour_flow(RNG & ran){
sort();
// initialise first
int colour = COLOUR_OFFSET;
int anti_colour = colour+1;
// -1 anti, 0 no, +1 colour
int is_quark_line = connect_incoming(incoming[0], colour, anti_colour);
for(auto & part: outgoing){
std::cout << part.type << " " << part.rapidity() << " " << colour
<< " " << anti_colour << " " << is_quark_line << std::endl;
- // if g:
- // if only 1 colour (quark line): connect and continue with anti (if not possible Error)
- // if 2 colours (gluon line): connect to colour or anti at random
if(part.type == ParticleID::gluon){
- if(is_quark_line == 0){ // on g line
- if(ran.flat() < 0.5){ // connect colour
+ // gluon
+ if(is_quark_line == 0){
+ // on g line => connect to colour OR anti-colour (random)
+ if(ran.flat() < 0.5){
part.colour = std::make_pair(colour+2,colour);
colour+=2;
- } else { // connect anti-colour
+ } else {
part.colour = std::make_pair(anti_colour, anti_colour+2);
anti_colour+=2;
}
- } else if(is_quark_line > 0){ // on q line
+ } else if(is_quark_line > 0){
+ // on q line => connect to available colour
part.colour = std::make_pair(colour+2, colour);
colour+=2;
- } else { // on qx line
+ } else {
+ // on qx line => connect to available anti-colour
part.colour = std::make_pair(anti_colour, anti_colour+2);
anti_colour+=2;
}
- // if q:
- // if only 1 colour: (quark line): add second
- // if 2 colours (gluon line): connect and don't put out more
} else if(is_quark(part)) {
- if(is_quark_line == 0){ // on g line
+ // quark
+ if(is_quark_line == 0){
+ // on g line => connect and remove colour
is_quark_line = 1;
part.colour = std::make_pair(anti_colour, 0);
anti_colour+=2;
anti_colour*=-1;
- } else if(is_quark_line < 0){ // on qx line
+ } else if(is_quark_line < 0){
+ // on qx line => new colour
is_quark_line = 0;
colour*=-1;
- colour+=2;
part.colour = std::make_pair(colour,0);
} else {
- throw std::logic_error("Creation of colour connection failed: Expected anti-quark but found quark.");
+ throw std::logic_error("Colour connection impossible: Expected anti-quark but found quark.");
}
} else if(is_antiquark(part)) {
- if(is_quark_line == 0){ // on g line
+ // anti-quark
+ if(is_quark_line == 0){
+ // on g line => connect and remove anti-colour
is_quark_line = -1;
part.colour = std::make_pair(0, colour);
colour+=2;
colour*=-1;
- } else if(is_quark_line > 0){ // on q line
+ } else if(is_quark_line > 0){
+ // on q line => new anti-colour
is_quark_line = 0;
- anti_colour+=2;
anti_colour*=-1;
part.colour = std::make_pair(0,anti_colour);
} else {
- throw std::logic_error("Creation of colour connection failed: Expected quark but found anti-quark.");
+ throw std::logic_error("Colour connection impossible: Expected quark but found anti-quark.");
}
}
}
// Connect last
- connect_incoming(incoming[1], colour, anti_colour);
+ connect_incoming(incoming[1], anti_colour, colour);
}
void UnclusteredEvent::sort(){
// sort incoming
std::sort(
begin(incoming), end(incoming),
[](Particle o1, Particle o2){return o1.p.pz()<o2.p.pz();}
);
//sort outgoing
if(std::is_sorted(begin(outgoing), end(outgoing), rapidity_less{}))
return;
auto old_outgoing = std::move(outgoing);
std::vector<size_t> idx(old_outgoing.size());
std::iota(idx.begin(), idx.end(), 0);
std::sort(idx.begin(), idx.end(), [&old_outgoing](size_t i, size_t j){
return old_outgoing[i].rapidity() < old_outgoing[j].rapidity();
});
outgoing.clear();
outgoing.reserve(old_outgoing.size());
for(size_t i: idx) {
outgoing.emplace_back(std::move(old_outgoing[i]));
}
// find decays again
if(!decays.empty()){
auto old_decays = std::move(decays);
decays.clear();
for(size_t i=0; i<idx.size(); ++i) {
auto decay = old_decays.find(idx[i]);
if(decay != old_decays.end())
decays.emplace(i, std::move(decay->second));
}
assert(old_decays.size() == decays.size());
}
}
Event::Event(
UnclusteredEvent ev,
fastjet::JetDefinition const & jet_def, double min_jet_pt
):
ev_{std::move(ev)},
cs_{to_PseudoJet(filter_partons(ev_.outgoing)), jet_def},
min_jet_pt_{min_jet_pt}
{
// sort particles
ev_.sort();
// classify event
type_ = classify(*this);
assert(std::is_sorted(begin(outgoing()), end(outgoing()), rapidity_less{}));
}
std::vector<fastjet::PseudoJet> Event::jets() const{
return cs_.inclusive_jets(min_jet_pt_);
}
double shat(Event const & ev){
return (ev.incoming()[0].p + ev.incoming()[1].p).m2();
}
namespace{
// colour flow according to Les Houches standard
// TODO: stub
std::vector<std::pair<int, int>> colour_flow(
std::array<Particle, 2> const & incoming,
std::vector<Particle> const & outgoing
){
std::vector<std::pair<int, int>> result(
incoming.size() + outgoing.size()
);
for(auto & col: result){
col = std::make_pair(-1, -1);
}
return result;
}
}
LHEF::HEPEUP to_HEPEUP(Event const & event, LHEF::HEPRUP * heprup){
LHEF::HEPEUP result;
result.heprup = heprup;
result.weights = {{event.central().weight, nullptr}};
for(auto const & var: event.variations()){
result.weights.emplace_back(var.weight, nullptr);
}
size_t num_particles = event.incoming().size() + event.outgoing().size();
for(auto const & decay: event.decays()) num_particles += decay.second.size();
result.NUP = num_particles;
// the following entries are pretty much meaningless
result.IDPRUP = event.type()+1; // event ID
result.AQEDUP = 1./128.; // alpha_EW
//result.AQCDUP = 0.118 // alpha_QCD
// end meaningless part
result.XWGTUP = event.central().weight;
result.SCALUP = event.central().muf;
result.scales.muf = event.central().muf;
result.scales.mur = event.central().mur;
result.scales.SCALUP = event.central().muf;
result.pdfinfo.p1 = event.incoming().front().type;
result.pdfinfo.p2 = event.incoming().back().type;
result.pdfinfo.scale = event.central().muf;
for(Particle const & in: event.incoming()){
result.IDUP.emplace_back(in.type);
result.ISTUP.emplace_back(status_in);
result.PUP.push_back({in.p[0], in.p[1], in.p[2], in.p[3], in.p.m()});
result.MOTHUP.emplace_back(0, 0);
}
for(size_t i = 0; i < event.outgoing().size(); ++i){
Particle const & out = event.outgoing()[i];
result.IDUP.emplace_back(out.type);
const int status = event.decays().count(i)?status_decayed:status_out;
result.ISTUP.emplace_back(status);
result.PUP.push_back({out.p[0], out.p[1], out.p[2], out.p[3], out.p.m()});
result.MOTHUP.emplace_back(1, 2);
}
result.ICOLUP = colour_flow(
event.incoming(), filter_partons(event.outgoing())
);
if(result.ICOLUP.size() < num_particles){
const size_t AWZH_boson_idx = std::find_if(
begin(event.outgoing()), end(event.outgoing()),
[](Particle const & s){ return is_AWZH_boson(s); }
) - begin(event.outgoing()) + event.incoming().size();
assert(AWZH_boson_idx <= result.ICOLUP.size());
result.ICOLUP.insert(
begin(result.ICOLUP) + AWZH_boson_idx,
std::make_pair(0,0)
);
}
for(auto const & decay: event.decays()){
for(auto const out: decay.second){
result.IDUP.emplace_back(out.type);
result.ISTUP.emplace_back(status_out);
result.PUP.push_back({out.p[0], out.p[1], out.p[2], out.p[3], out.p.m()});
const size_t mother_idx = 1 + event.incoming().size() + decay.first;
result.MOTHUP.emplace_back(mother_idx, mother_idx);
result.ICOLUP.emplace_back(0,0);
}
}
assert(result.ICOLUP.size() == num_particles);
static constexpr double unknown_spin = 9.; //per Les Houches accord
result.VTIMUP = std::vector<double>(num_particles, unknown_spin);
result.SPINUP = result.VTIMUP;
return result;
}
}

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