def add_affine_cuts(nlp_result, solve_data, config):
with time_code(solve_data.timing, "affine cut generation"):
m = solve_data.linear_GDP
if config.calc_disjunctive_bounds:
with time_code(solve_data.timing, "disjunctive variable bounding"):
TransformationFactory(
'contrib.compute_disj_var_bounds').apply_to(
m,
solver=config.mip_solver
if config.obbt_disjunctive_bounds else None)
config.logger.info("Adding affine cuts.")
GDPopt = m.GDPopt_utils
counter = 0
for var, val in zip(GDPopt.variable_list, nlp_result.var_values):
if val is not None and not var.fixed:
var.value = val
for constr in constraints_in_True_disjuncts(m, config):
# Note: this includes constraints that are deactivated in the current model (linear_GDP)
disjunctive_var_bounds = disjunctive_bounds(constr.parent_block())
if constr.body.polynomial_degree() in (1, 0):
continue
vars_in_constr = list(identify_variables(constr.body))
if any(var.value is None for var in vars_in_constr):
continue # a variable has no values
# mcpp stuff
mc_eqn = mc(constr.body, disjunctive_var_bounds)
# mc_eqn = mc(constr.body)
ccSlope = mc_eqn.subcc()
cvSlope = mc_eqn.subcv()
ccStart = mc_eqn.concave()
cvStart = mc_eqn.convex()
ub_int = min(
constr.upper,
mc_eqn.upper()) if constr.has_ub() else mc_eqn.upper()
lb_int = max(
constr.lower,
mc_eqn.lower()) if constr.has_lb() else mc_eqn.lower()
parent_block = constr.parent_block()
# Create a block on which to put outer approximation cuts.
aff_utils = parent_block.component('GDPopt_aff')
if aff_utils is None:
aff_utils = parent_block.GDPopt_aff = Block(
doc="Block holding affine constraints")
aff_utils.GDPopt_aff_cons = ConstraintList()
aff_cuts = aff_utils.GDPopt_aff_cons
concave_cut = sum(ccSlope[var] * (var - var.value)
for var in vars_in_constr) + ccStart >= lb_int
convex_cut = sum(cvSlope[var] * (var - var.value)
for var in vars_in_constr) + cvStart <= ub_int
aff_cuts.add(expr=concave_cut)
aff_cuts.add(expr=convex_cut)
counter += 2
config.logger.info("Added %s affine cuts" % counter)
def add_affine_cuts(nlp_result, solve_data, config):
with time_code(solve_data.timing, "affine cut generation"):
m = solve_data.linear_GDP
if config.calc_disjunctive_bounds:
with time_code(solve_data.timing, "disjunctive variable bounding"):
TransformationFactory('contrib.compute_disj_var_bounds').apply_to(
m,
solver=config.mip_solver if config.obbt_disjunctive_bounds else None
)
config.logger.info("Adding affine cuts.")
GDPopt = m.GDPopt_utils
counter = 0
for var, val in zip(GDPopt.variable_list, nlp_result.var_values):
if val is not None and not var.fixed:
var.value = val
for constr in constraints_in_True_disjuncts(m, config):
# Note: this includes constraints that are deactivated in the current model (linear_GDP)
disjunctive_var_bounds = disjunctive_bounds(constr.parent_block())
if constr.body.polynomial_degree() in (1, 0):
continue
vars_in_constr = list(
identify_variables(constr.body))
if any(var.value is None for var in vars_in_constr):
continue # a variable has no values
# mcpp stuff
mc_eqn = mc(constr.body, disjunctive_var_bounds)
# mc_eqn = mc(constr.body)
ccSlope = mc_eqn.subcc()
cvSlope = mc_eqn.subcv()
ccStart = mc_eqn.concave()
cvStart = mc_eqn.convex()
ub_int = min(constr.upper, mc_eqn.upper()) if constr.has_ub() else mc_eqn.upper()
lb_int = max(constr.lower, mc_eqn.lower()) if constr.has_lb() else mc_eqn.lower()
parent_block = constr.parent_block()
# Create a block on which to put outer approximation cuts.
aff_utils = parent_block.component('GDPopt_aff')
if aff_utils is None:
aff_utils = parent_block.GDPopt_aff = Block(
doc="Block holding affine constraints")
aff_utils.GDPopt_aff_cons = ConstraintList()
aff_cuts = aff_utils.GDPopt_aff_cons
concave_cut = sum(ccSlope[var] * (var - var.value)
for var in vars_in_constr
) + ccStart >= lb_int
convex_cut = sum(cvSlope[var] * (var - var.value)
for var in vars_in_constr
) + cvStart <= ub_int
aff_cuts.add(expr=concave_cut)
aff_cuts.add(expr=convex_cut)
counter += 2
config.logger.info("Added %s affine cuts" % counter)
