'''
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 pkgutil
import os
# not available in the latest version of PM4Py
CVXOPT = "cvxopt"
PULP = "pulp"
SCIPY = "scipy"
# not available in the latest version of PM4Py
CVXOPT_SOLVER_CUSTOM_ALIGN = "cvxopt_solver_custom_align"
CVXOPT_SOLVER_CUSTOM_ALIGN_ILP = "cvxopt_solver_custom_align_ilp"
# max allowed heuristics value (27/10/2019, due to the numerical instability of some of our solvers)
MAX_ALLOWED_HEURISTICS = 10 ** 15
VERSIONS_APPLY = {}
VERSIONS_GET_PRIM_OBJ = {}
VERSIONS_GET_POINTS_FROM_SOL = {}
DEFAULT_LP_SOLVER_VARIANT = None
if pkgutil.find_loader("pulp"):
# assuming pulp is installed
from pm4py.util.lp.variants import pulp_solver
VERSIONS_APPLY[PULP] = pulp_solver.apply
VERSIONS_GET_PRIM_OBJ[PULP] = pulp_solver.get_prim_obj_from_sol
VERSIONS_GET_POINTS_FROM_SOL[PULP] = pulp_solver.get_points_from_sol
DEFAULT_LP_SOLVER_VARIANT = PULP
if pkgutil.find_loader("scipy"):
# in the case scipy is installed, it works
from pm4py.util.lp.variants import scipy_solver
VERSIONS_APPLY[SCIPY] = scipy_solver.apply
VERSIONS_GET_PRIM_OBJ[SCIPY] = scipy_solver.get_prim_obj_from_sol
VERSIONS_GET_POINTS_FROM_SOL[SCIPY] = scipy_solver.get_points_from_sol
DEFAULT_LP_SOLVER_VARIANT = SCIPY
if pkgutil.find_loader("cvxopt"):
from pm4py.util.lp.variants import cvxopt_solver, cvxopt_solver_custom_align, cvxopt_solver_custom_align_ilp, \
cvxopt_solver_custom_align_arm
custom_solver = cvxopt_solver_custom_align
try:
# for ARM-based Linux, we need to use a different call to GLPK
if "arm" in str(os.uname()[-1]):
custom_solver = cvxopt_solver
except:
pass
CVXOPT = "cvxopt"
CVXOPT_SOLVER_CUSTOM_ALIGN = "cvxopt_solver_custom_align"
CVXOPT_SOLVER_CUSTOM_ALIGN_ILP = "cvxopt_solver_custom_align_ilp"
VERSIONS_APPLY[CVXOPT] = cvxopt_solver.apply
VERSIONS_GET_PRIM_OBJ[CVXOPT] = cvxopt_solver.get_prim_obj_from_sol
VERSIONS_GET_POINTS_FROM_SOL[CVXOPT] = cvxopt_solver.get_points_from_sol
VERSIONS_APPLY[CVXOPT_SOLVER_CUSTOM_ALIGN] = custom_solver.apply
VERSIONS_GET_PRIM_OBJ[CVXOPT_SOLVER_CUSTOM_ALIGN] = custom_solver.get_prim_obj_from_sol
VERSIONS_GET_POINTS_FROM_SOL[CVXOPT_SOLVER_CUSTOM_ALIGN] = custom_solver.get_points_from_sol
VERSIONS_APPLY[CVXOPT_SOLVER_CUSTOM_ALIGN_ILP] = cvxopt_solver_custom_align_ilp.apply
VERSIONS_GET_PRIM_OBJ[
CVXOPT_SOLVER_CUSTOM_ALIGN_ILP] = cvxopt_solver_custom_align_ilp.get_prim_obj_from_sol
VERSIONS_GET_POINTS_FROM_SOL[
CVXOPT_SOLVER_CUSTOM_ALIGN_ILP] = cvxopt_solver_custom_align_ilp.get_points_from_sol
DEFAULT_LP_SOLVER_VARIANT = CVXOPT_SOLVER_CUSTOM_ALIGN
[docs]def apply(c, Aub, bub, Aeq, beq, parameters=None, variant=DEFAULT_LP_SOLVER_VARIANT):
"""
Gets the overall solution of the problem
Parameters
------------
c
c parameter of the algorithm
Aub
A_ub parameter of the algorithm
bub
b_ub parameter of the algorithm
Aeq
A_eq parameter of the algorithm
beq
b_eq parameter of the algorithm
parameters
Possible parameters of the algorithm
variant
Variant of the algorithm, possible values: pulp, scipy
Returns
-------------
sol
Solution of the LP problem by the given algorithm
"""
return VERSIONS_APPLY[variant](c, Aub, bub, Aeq, beq, parameters=parameters)
[docs]def get_prim_obj_from_sol(sol, parameters=None, variant=DEFAULT_LP_SOLVER_VARIANT):
"""
Gets the primal objective from the solution of the LP problem
Parameters
-------------
sol
Solution of the ILP problem by the given algorithm
parameters
Possible parameters of the algorithm
variant
Variant of the algorithm, possible values: pulp, scipy
Returns
-------------
prim_obj
Primal objective
"""
return VERSIONS_GET_PRIM_OBJ[variant](sol, parameters=parameters)
[docs]def get_points_from_sol(sol, parameters=None, variant=DEFAULT_LP_SOLVER_VARIANT):
"""
Gets the points from the solution
Parameters
-------------
sol
Solution of the LP problem by the given algorithm
parameters
Possible parameters of the algorithm
variant
Variant of the algorithm, possible values: pulp, scipy
Returns
-------------
points
Point of the solution
"""
return VERSIONS_GET_POINTS_FROM_SOL[variant](sol, parameters=parameters)