|
FastJet 3.0alpha3
|
|
FastJet 3.0alpha3
|
Parameters to configure the computation of jet areas using ghosts. More...
#include <GhostedAreaSpec.hh>
Public Member Functions | |
| GhostedAreaSpec () | |
| default constructor | |
| GhostedAreaSpec (double ghost_maxrap, int repeat=gas::def_repeat, double ghost_area=gas::def_ghost_area, double grid_scatter=gas::def_grid_scatter, double kt_scatter=gas::def_kt_scatter, double mean_ghost_kt=gas::def_mean_ghost_kt) | |
| explicit constructor | |
| GhostedAreaSpec (double ghost_minrap, double ghost_maxrap, int repeat=gas::def_repeat, double ghost_area=gas::def_ghost_area, double grid_scatter=gas::def_grid_scatter, double kt_scatter=gas::def_kt_scatter, double mean_ghost_kt=gas::def_mean_ghost_kt) | |
| explicit constructor | |
| GhostedAreaSpec (const Selector &selector, int repeat=gas::def_repeat, double ghost_area=gas::def_ghost_area, double grid_scatter=gas::def_grid_scatter, double kt_scatter=gas::def_kt_scatter, double mean_ghost_kt=gas::def_mean_ghost_kt) | |
| constructor based on a Selector | |
| void | _initialize () |
| does the initialization of actual ghost parameters | |
| double | ghost_etamax () const |
| double | ghost_maxrap () const |
| double | ghost_area () const |
| double | grid_scatter () const |
| double | kt_scatter () const |
| double | mean_ghost_kt () const |
| int | repeat () const |
| double | actual_ghost_area () const |
| int | n_ghosts () const |
| void | set_ghost_area (double val) |
| void | set_ghost_etamax (double val) |
| void | set_ghost_maxrap (double val) |
| void | set_grid_scatter (double val) |
| void | set_kt_scatter (double val) |
| void | set_mean_ghost_kt (double val) |
| void | set_repeat (int val) |
| int | nphi () const |
| return nphi (ghosts layed out (-nrap, 0..nphi-1), (-nrap+1,0..nphi-1), ... | |
| int | nrap () const |
| void | get_random_status (std::vector< int > &__iseed) const |
| get all relevant information about the status of the random number generator, so that it can be reset subsequently with set_random_status. | |
| void | set_random_status (const std::vector< int > &__iseed) |
| set the status of the random number generator, as obtained previously with get_random_status. | |
| void | checkpoint_random () |
| void | restore_checkpoint_random () |
| std::string | description () const |
| for a summary | |
| void | add_ghosts (std::vector< PseudoJet > &) const |
| push a set of ghost 4-momenta onto the back of the vector of PseudoJets | |
| double | random_at_own_risk () const |
| very deprecated public access to a random number from the internal generator | |
| BasicRandom< double > & | generator_at_own_risk () const |
| very deprecated public access to the generator itself | |
Parameters to configure the computation of jet areas using ghosts.
Class that defines the parameters that go into the measurement of active jet areas.
Definition at line 63 of file GhostedAreaSpec.hh.
| fastjet::GhostedAreaSpec::GhostedAreaSpec | ( | const Selector & | selector, |
| int | repeat = gas::def_repeat, |
||
| double | ghost_area = gas::def_ghost_area, |
||
| double | grid_scatter = gas::def_grid_scatter, |
||
| double | kt_scatter = gas::def_kt_scatter, |
||
| double | mean_ghost_kt = gas::def_mean_ghost_kt |
||
| ) | [explicit] |
constructor based on a Selector
explicit constructor
Definition at line 43 of file GhostedAreaSpec.cc.
References _initialize(), fastjet::Selector::applies_jet_by_jet(), fastjet::Selector::get_rapidity_extent(), and fastjet::Selector::has_finite_area().
:
_repeat(repeat),
_ghost_area(ghost_area),
_grid_scatter(grid_scatter),
_kt_scatter(kt_scatter),
_mean_ghost_kt(mean_ghost_kt),
_selector(selector),
_actual_ghost_area(-1.0)
{
// check the selector has the properties needed -- an area and
// applicability jet-by-jet (the latter follows automatically from
// the former?)
if (!_selector.has_finite_area()) throw Error("To construct a GhostedAreaSpec with a Selector, the selector must have a finite area");
if (!_selector.applies_jet_by_jet()) throw Error("To construct a GhostedAreaSpec with a Selector, the selector must apply jet-by-jet");
// get the internal rapidity extent from the selector
double ghost_maxrap, ghost_minrap;
_selector.get_rapidity_extent(ghost_minrap, ghost_maxrap);
_ghost_maxrap = 0.5*(ghost_maxrap - ghost_minrap);
_ghost_rap_offset = 0.5*(ghost_maxrap + ghost_minrap);
_initialize();
}
| void fastjet::GhostedAreaSpec::_initialize | ( | ) |
does the initialization of actual ghost parameters
sets the detailed parameters for the ghosts (which may not be quite the same as those requested -- this is in order for things to fit in nicely into 2pi etc...
Definition at line 77 of file GhostedAreaSpec.cc.
Referenced by GhostedAreaSpec().
{
// add on area-measuring dummy particles
_drap = sqrt(_ghost_area);
_dphi = _drap;
_nphi = int(ceil(twopi/_dphi)); _dphi = twopi/_nphi;
_nrap = int(ceil(_ghost_maxrap/_drap)); _drap = _ghost_maxrap / _nrap;
_actual_ghost_area = _dphi * _drap;
_n_ghosts = (2*_nrap+1)*_nphi;
// checkpoint the status of the random number generator.
checkpoint_random();
//_random_generator.info(cerr);
}
| int fastjet::GhostedAreaSpec::nphi | ( | ) | const [inline] |
return nphi (ghosts layed out (-nrap, 0..nphi-1), (-nrap+1,0..nphi-1), ...
(nrap,0..nphi-1)
Definition at line 148 of file GhostedAreaSpec.hh.
{return _nphi;}
| void fastjet::GhostedAreaSpec::get_random_status | ( | std::vector< int > & | __iseed | ) | const [inline] |
get all relevant information about the status of the random number generator, so that it can be reset subsequently with set_random_status.
Definition at line 154 of file GhostedAreaSpec.hh.
{
_random_generator.get_status(__iseed);}
| void fastjet::GhostedAreaSpec::set_random_status | ( | const std::vector< int > & | __iseed | ) | [inline] |
set the status of the random number generator, as obtained previously with get_random_status.
Note that the random generator is a static member of the class, i.e. common to all instances of the class --- so if you modify the random for this instance, you modify it for all instances.
Definition at line 162 of file GhostedAreaSpec.hh.
{
_random_generator.set_status(__iseed);}
| void fastjet::GhostedAreaSpec::add_ghosts | ( | std::vector< PseudoJet > & | ) | const |
push a set of ghost 4-momenta onto the back of the vector of PseudoJets
adds the ghost 4-momenta to the vector of PseudoJet's
Definition at line 93 of file GhostedAreaSpec.cc.
References fastjet::SharedPtr< T >::get(), fastjet::Selector::pass(), fastjet::PseudoJet::set_cached_rap_phi(), and fastjet::Selector::worker().
Referenced by fastjet::Selector::area().
{
// add momenta for ghosts
for (int irap = -_nrap; irap <= _nrap; irap++) {
for (int iphi = 0; iphi < _nphi; iphi++) {
// include random offsets for all quantities
//----------------------------------------------
// NB: in FJ2 we'd exchanged the px and py components relative to a
// standard definition of phi; to preserve the same areas as fj2
// we now generate a "phi_fj2", and then convert to a standard phi
double phi_fj2 = (iphi+0.5) * _dphi + _dphi*(_our_rand()-0.5)*_grid_scatter;
double phi = 0.5*pi - phi_fj2;
double rap = irap * _drap + _drap*(_our_rand()-0.5)*_grid_scatter
+ _ghost_rap_offset ;
double kt = _mean_ghost_kt*(1+(_our_rand()-0.5)*_kt_scatter);
double exprap = exp(+rap);
double pminus = kt/exprap;
double pplus = kt*exprap;
double px = kt*cos(phi);
double py = kt*sin(phi);
PseudoJet mom(px,py,0.5*(pplus-pminus),0.5*(pplus+pminus));
// this call fills in the PseudoJet's cached rap,phi information,
// based on pre-existing knowledge. Watch out: if you get the hint
// wrong nobody will tell you, but you will certainly mess up
// your results.
mom.set_cached_rap_phi(rap,phi);
// if we have an active selector and the particle does not pass the
// selection condition, move on to the next momentum
if (_selector.worker().get() && !_selector.pass(mom)) continue;
event.push_back(mom);
}
}
}
1.7.4