Sense (minimize/maximize) of l_objective added.

pypsa/opt.py

@@ -38,7 +38,7 @@
 logger = logging.getLogger(__name__)
 
 
-from pyomo.environ import Constraint, Objective, Var, ComponentUID
+from pyomo.environ import Constraint, Objective, Var, ComponentUID, minimize, maximize
 from weakref import ref as weakref_ref
 
 import pyomo
@@ -248,7 +248,7 @@ def l_constraint(model,name,constraints,*args):
  v._data[i]._upper = pyomo.core.base.numvalue.NumericConstant(constant[1])
  else: raise KeyError('`sense` must be one of "==","<=",">=","><"; got: {}'.format(sense))
 
-def l_objective(model,objective=None):
+def l_objective(model,objective=None, sense=minimize):
  """
  A replacement for pyomo's Objective that quickly builds linear
  objectives.
@@ -259,7 +259,7 @@ def l_objective(model,objective=None):
 
  call instead
 
- l_objective(model,objective)
+ l_objective(model,objective,sense)
 
  where objective is an LExpression.
 
@@ -271,14 +271,15 @@ def l_objective(model,objective=None):
  ----------
  model : pyomo.environ.ConcreteModel
  objective : LExpression
+ sense : minimize / maximize
 
  """
 
  if objective is None:
  objective = LExpression()
 
  #initialise with a dummy
- model.objective = Objective(expr = 0.)
+ model.objective = Objective(expr = 0., sense=sense)
  model.objective._expr = _build_sum_expression(objective.variables, constant=objective.constant)
 
 def free_pyomo_initializers(obj):