#################################################################################
# The Institute for the Design of Advanced Energy Systems Integrated Platform
# Framework (IDAES IP) was produced under the DOE Institute for the
# Design of Advanced Energy Systems (IDAES).
#
# Copyright (c) 2018-2023 by the software owners: The Regents of the
# University of California, through Lawrence Berkeley National Laboratory,
# National Technology & Engineering Solutions of Sandia, LLC, Carnegie Mellon
# University, West Virginia University Research Corporation, et al.
# All rights reserved. Please see the files COPYRIGHT.md and LICENSE.md
# for full copyright and license information.
#################################################################################
"""
Initializer class for implementing Block Triangularization initialization
"""
from pyomo.environ import SolverFactory
from pyomo.common.config import ConfigDict, ConfigValue, add_docstring_list
from pyomo.contrib.incidence_analysis import (
IncidenceGraphInterface,
solve_strongly_connected_components,
)
from idaes.core.initialization.initializer_base import (
InitializerBase,
InitializationStatus,
)
from idaes.core.util.exceptions import InitializationError
from idaes.core.solvers import get_solver
__author__ = "Andrew Lee"
[docs]class BlockTriangularizationInitializer(InitializerBase):
"""
Block Triangularization based Initializer object.
This Initializer should be suitable for most models, but may struggle to initialize
tightly coupled systems of equations.
This Initializer uses the common workflow defined in InitializerBase and calls
the Pyomo solve_strongly_connected_components function to initialize the model.
"""
CONFIG = InitializerBase.CONFIG()
CONFIG.declare(
"block_solver",
ConfigValue(
default="scipy.fsolve",
description="Solver to use for NxN blocks",
),
)
CONFIG.declare(
"block_solver_options",
ConfigDict(
implicit=True,
description="Dict of options to pass to block solver",
),
)
CONFIG.declare(
"calculate_variable_options",
ConfigDict(
implicit=True,
description="Dict of options to pass to 1x1 block solver",
doc="Dict of options to pass to calc_var_kwds argument in "
"solve_strongly_connected_components method. NOTE: models "
"involving ExternalFunctions must set "
"'diff_mode=differentiate.Modes.reverse_numeric'",
),
)
[docs] def precheck(self, model):
"""
Check for perfect matching in model.
If this fails, it indicates a structural singularity in the model.
"""
super().precheck(model)
igraph = IncidenceGraphInterface(model, include_inequality=False)
matching = igraph.maximum_matching()
if len(matching) != len(igraph.variables):
self._update_summary(model, "status", InitializationStatus.PrecheckFailed)
raise InitializationError(
f"Perfect matching not found for {model.name}. "
f"This suggests that the model is structurally singular."
)
def initialization_routine(self, model):
"""
Call Block Triangularization solver on model.
"""
if self.config.block_solver is not None:
solver = SolverFactory(self.config.block_solver)
else:
solver = get_solver(None)
# TODO: Can we get diagnostic output from this method?
solve_strongly_connected_components(
model,
solver=solver,
solve_kwds=self.config.block_solver_options,
calc_var_kwds=self.config.calculate_variable_options,
)