# -*- coding: utf-8 -*-
"""Constraints to relate variables in an existing model.
SPDX-FileCopyrightText: jnnr
SPDX-License-Identifier: MIT
"""
from pyomo import environ as po
[docs]def equate_flows(model, flows1, flows2, factor1=1, name="equate_flows"):
r"""
Adds a constraint to the given model that sets the sum of two groups of
flows equal or proportional by a factor for each timestep.
**The following constraints are built:**
.. math::
\text{factor\_1} \cdot
\sum_{\text{flow in flows1}} \text{flow}_{t} =
\sum_{\text{flow in flows2}} \text{flow}_t \forall t
Parameters
----------
model : oemof.solph.Model
Model to which the constraint is added.
flows1 : iterable
First group of flows, to be set to equal with Var2 and multiplied with
factor1.
flows2 : iterable
Second group of flows, to be set equal to (Var1 * factor1).
factor1 : numeric, default=1
Factor to define the proportion between the two groups.
name : str, default='equate_flows'
Name for the equation e.g. in the LP file.
Returns
-------
the updated model.
"""
def _equate_flow_groups_rule(m):
for p, ts in m.TIMEINDEX:
sum1_t = sum(m.flow[fi, fo, p, ts] for fi, fo in flows1)
sum2_t = sum(m.flow[fi, fo, p, ts] for fi, fo in flows2)
expr = sum1_t * factor1 == sum2_t
if expr is not True:
getattr(m, name).add((p, ts), expr)
setattr(
model,
name,
po.Constraint(model.TIMEINDEX, noruleinit=True),
)
setattr(
model,
name + "_build",
po.BuildAction(rule=_equate_flow_groups_rule),
)
return model
def equate_flows_by_keyword(
model, keyword1, keyword2, factor1=1, name="equate_flows"
):
r"""
This wrapper for equate_flows allows to equate groups of flows by using a
keyword instead of a list of flows.
Parameters
----------
model: oemof.solph.Model
Model to which constraints are added.
keyword1: string
keyword to consider (searches all Flows).
keyword2: string
keyword to consider (searches all Flows).
factor1 : numeric, default=1
Factor to define the proportion between the two groups.
name : str, default='equate_flows'
Name for the equation e.g. in the LP file.
Returns
-------
the updated model
See Also
--------
equate_flows(model, flows1, flows2,
factor1=1, name="equate_flows")
"""
flows = {}
for n, keyword in enumerate([keyword1, keyword2]):
flows[n] = []
for i, o in model.flows:
if hasattr(model.flows[i, o], keyword):
flows[n].append((i, o))
return equate_flows(model, flows[0], flows[1], factor1=factor1, name=name)
