Source code for pm4py.objects.petri.semantics

'''
    This file is part of PM4Py (More Info: https://pm4py.fit.fraunhofer.de).

    PM4Py is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    PM4Py is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with PM4Py.  If not, see <https://www.gnu.org/licenses/>.
'''
import copy


[docs]def is_enabled(t, pn, m): """ Verifies whether a given transition is enabled in a given Petri net and marking Parameters ---------- :param t: transition to check :param pn: Petri net :param m: marking to check Returns ------- :return: true if enabled, false otherwise """ if t not in pn.transitions: return False else: for a in t.in_arcs: if m[a.source] < a.weight: return False return True
[docs]def execute(t, pn, m): """ Executes a given transition in a given Petri net and Marking Parameters ---------- :param t: transition to execute :param pn: Petri net :param m: marking to use Returns ------- :return: newly reached marking if :param t: is enabled, None otherwise """ if not is_enabled(t, pn, m): return None m_out = copy.copy(m) for a in t.in_arcs: m_out[a.source] -= a.weight if m_out[a.source] == 0: del m_out[a.source] for a in t.out_arcs: m_out[a.target] += a.weight return m_out
[docs]def try_to_execute(t, pn, m): if not is_enabled(t, pn, m): return None else: return execute(t, pn, m)
[docs]def weak_execute(t, m): """ Execute a transition even if it is not fully enabled Parameters ---------- :param t: transition to execute :param m: marking to use Returns ------- :return: newly reached marking if :param t: is enabled, None otherwise """ m_out = copy.copy(m) for a in t.in_arcs: m_out[a.source] -= a.weight if m_out[a.source] <= 0: del m_out[a.source] for a in t.out_arcs: m_out[a.target] += a.weight return m_out
[docs]def enabled_transitions(pn, m): """ Returns a set of enabled transitions in a Petri net and given marking Parameters ---------- :param pn: Petri net :param m: marking of the pn Returns ------- :return: set of enabled transitions """ enabled = set() for t in pn.transitions: if is_enabled(t, pn, m): enabled.add(t) return enabled