# ___________________________________________________________________________ # # Pyomo: Python Optimization Modeling Objects # Copyright 2017 National Technology and Engineering Solutions of Sandia, LLC # Under the terms of Contract DE-NA0003525 with National Technology and # Engineering Solutions of Sandia, LLC, the U.S. Government retains certain # rights in this software. # This software is distributed under the 3-clause BSD License. # ___________________________________________________________________________ # # Problem Writer for BARON .bar Format Files # import itertools import logging import math from six import iteritems, StringIO from pyomo.common.collections import OrderedSet from pyomo.opt import ProblemFormat from pyomo.opt.base import AbstractProblemWriter, WriterFactory from pyomo.core.expr.numvalue import ( value, native_numeric_types, native_types, nonpyomo_leaf_types, ) from pyomo.core.expr import current as EXPR from pyomo.core.base import (SortComponents, SymbolMap, ShortNameLabeler, NumericLabeler, Constraint, Objective, Param) from pyomo.core.base.component import ActiveComponent #CLH: EXPORT suffixes "constraint_types" and "branching_priorities" # pass their respective information to the .bar file import pyomo.core.base.suffix import pyomo.core.kernel.suffix from pyomo.core.kernel.block import IBlock from pyomo.repn.util import valid_expr_ctypes_minlp, \ valid_active_ctypes_minlp, ftoa logger = logging.getLogger('pyomo.core') # # A visitor pattern that creates a string for an expression # that is compatible with the BARON syntax. # class ToBaronVisitor(EXPR.ExpressionValueVisitor): def __init__(self, variables, smap): super(ToBaronVisitor, self).__init__() self.variables = variables self.smap = smap def visit(self, node, values): """ Visit nodes that have been expanded """ tmp = [] for i,val in enumerate(values): arg = node._args_[i] if arg is None: tmp.append('Undefined') # TODO: coverage else: parens = False if val and val[0] in '-+': parens = True elif arg.__class__ in native_numeric_types: pass elif arg.__class__ in nonpyomo_leaf_types: val = "'{0}'".format(val) elif arg.is_expression_type(): if node._precedence() < arg._precedence(): parens = True elif node._precedence() == arg._precedence(): if i == 0: parens = node._associativity() != 1 elif i == len(node._args_)-1: parens = node._associativity() != -1 else: parens = True if parens: tmp.append("({0})".format(val)) else: tmp.append(val) if node.__class__ in EXPR.NPV_expression_types: return ftoa(value(node)) if node.__class__ is EXPR.LinearExpression: for v in node.linear_vars: self.variables.add(id(v)) if node.__class__ in { EXPR.ProductExpression, EXPR.MonomialTermExpression}: if tmp[0] in node._to_string.minus_one: return "- {0}".format(tmp[1]) if tmp[0] in node._to_string.one: return tmp[1] return "{0} * {1}".format(tmp[0], tmp[1]) elif node.__class__ is EXPR.PowExpression: x,y = node.args if type(x) not in native_types and not x.is_fixed() and \ type(y) not in native_types and not y.is_fixed(): # Per the BARON manual, x ^ y is allowed as long as x # and y are not both variables return "exp(({1}) * log({0}))".format(tmp[0], tmp[1]) else: return "{0} ^ {1}".format(tmp[0], tmp[1]) elif node.__class__ is EXPR.UnaryFunctionExpression: if node.name == "sqrt": return "{0} ^ 0.5".format(tmp[0]) elif node.name == 'log10': return "{0} * log({1})".format(math.log10(math.e), tmp[0]) elif node.name in {'exp','log'}: return node._to_string(tmp, None, self.smap, True) else: raise RuntimeError( 'The BARON .BAR format does not support the unary ' 'function "%s".' % (node.name,)) elif node.__class__ is EXPR.AbsExpression: return "({0} ^ 2) ^ 0.5".format(tmp[0]) else: return node._to_string(tmp, None, self.smap, True) def visiting_potential_leaf(self, node): """ Visiting a potential leaf. Return True if the node is not expanded. """ #print("ISLEAF") #print(node.__class__) if node is None: return True, None if node.__class__ in native_types: return True, ftoa(node) if node.is_expression_type(): # we will descend into this, so type checking will happen later return False, None if node.is_component_type(): _ctype = node.ctype if _ctype not in valid_expr_ctypes_minlp: # Make sure all components in active constraints # are basic ctypes we know how to deal with. raise RuntimeError( "Unallowable component '%s' of type %s found in an active " "constraint or objective.\nThe GAMS writer cannot export " "expressions with this component type." % (node.name, _ctype.__name__)) if node.is_variable_type(): if node.fixed: return True, ftoa(value(node)) else: self.variables.add(id(node)) label = self.smap.getSymbol(node) return True, label return True, ftoa(value(node)) def expression_to_string(expr, variables, labeler=None, smap=None): if labeler is not None: if smap is None: smap = SymbolMap() smap.default_labeler = labeler visitor = ToBaronVisitor(variables, smap) return visitor.dfs_postorder_stack(expr) # TODO: The to_string function is handy, but the fact that # it calls .name under the hood for all components # everywhere they are used will present ENORMOUS # overhead for components that have a large index set. # It might be worth adding an extra keyword to that # function that takes a "labeler" or "symbol_map" for # writing non-expression components. @WriterFactory.register('bar', 'Generate the corresponding BARON BAR file.') class ProblemWriter_bar(AbstractProblemWriter): def __init__(self): AbstractProblemWriter.__init__(self, ProblemFormat.bar) def _write_equations_section(self, model, output_file, all_blocks_list, active_components_data_var, symbol_map, c_labeler, output_fixed_variable_bounds, skip_trivial_constraints, sorter): referenced_variable_ids = OrderedSet() def _skip_trivial(constraint_data): if skip_trivial_constraints: if constraint_data._linear_canonical_form: repn = constraint_data.canonical_form() if (repn.variables is None) or \ (len(repn.variables) == 0): return True elif constraint_data.body.polynomial_degree() == 0: return True return False # # Check for active suffixes to export # if isinstance(model, IBlock): suffix_gen = lambda b: ((suf.storage_key, suf) \ for suf in pyomo.core.kernel.suffix.\ export_suffix_generator(b, active=True, descend_into=False)) else: suffix_gen = lambda b: pyomo.core.base.suffix.\ active_export_suffix_generator(b) r_o_eqns = [] c_eqns = [] l_eqns = [] branching_priorities_suffixes = [] for block in all_blocks_list: for name, suffix in suffix_gen(block): if name == 'branching_priorities': branching_priorities_suffixes.append(suffix) elif name == 'constraint_types': for constraint_data, constraint_type in iteritems(suffix): if not _skip_trivial(constraint_data): if constraint_type.lower() == 'relaxationonly': r_o_eqns.append(constraint_data) elif constraint_type.lower() == 'convex': c_eqns.append(constraint_data) elif constraint_type.lower() == 'local': l_eqns.append(constraint_data) else: raise ValueError( "A suffix '%s' contained an invalid value: %s\n" "Choices are: [relaxationonly, convex, local]" % (suffix.name, constraint_type)) else: raise ValueError( "The BARON writer can not export suffix with name '%s'. " "Either remove it from block '%s' or deactivate it." % (block.name, name)) non_standard_eqns = r_o_eqns + c_eqns + l_eqns # # EQUATIONS # #Equation Declaration n_roeqns = len(r_o_eqns) n_ceqns = len(c_eqns) n_leqns = len(l_eqns) eqns = [] # Alias the constraints by declaration order since Baron does not # include the constraint names in the solution file. It is important # that this alias not clash with any real constraint labels, hence # the use of the ".c" template. It is not possible to declare # a component having this type of name when using standard syntax. # There are ways to do it, but it is unlikely someone will. order_counter = 0 alias_template = ".c%d" output_file.write('EQUATIONS ') output_file.write("c_e_FIX_ONE_VAR_CONST__") order_counter += 1 for block in all_blocks_list: for constraint_data in block.component_data_objects(Constraint, active=True, sort=sorter, descend_into=False): if (not constraint_data.has_lb()) and \ (not constraint_data.has_ub()): assert not constraint_data.equality continue # non-binding, so skip if (not _skip_trivial(constraint_data)) and \ (constraint_data not in non_standard_eqns): eqns.append(constraint_data) con_symbol = symbol_map.createSymbol(constraint_data, c_labeler) assert not con_symbol.startswith('.') assert con_symbol != "c_e_FIX_ONE_VAR_CONST__" symbol_map.alias(constraint_data, alias_template % order_counter) output_file.write(", "+str(con_symbol)) order_counter += 1 output_file.write(";\n\n") if n_roeqns > 0: output_file.write('RELAXATION_ONLY_EQUATIONS ') for i, constraint_data in enumerate(r_o_eqns): con_symbol = symbol_map.createSymbol(constraint_data, c_labeler) assert not con_symbol.startswith('.') assert con_symbol != "c_e_FIX_ONE_VAR_CONST__" symbol_map.alias(constraint_data, alias_template % order_counter) if i == n_roeqns-1: output_file.write(str(con_symbol)+';\n\n') else: output_file.write(str(con_symbol)+', ') order_counter += 1 if n_ceqns > 0: output_file.write('CONVEX_EQUATIONS ') for i, constraint_data in enumerate(c_eqns): con_symbol = symbol_map.createSymbol(constraint_data, c_labeler) assert not con_symbol.startswith('.') assert con_symbol != "c_e_FIX_ONE_VAR_CONST__" symbol_map.alias(constraint_data, alias_template % order_counter) if i == n_ceqns-1: output_file.write(str(con_symbol)+';\n\n') else: output_file.write(str(con_symbol)+', ') order_counter += 1 if n_leqns > 0: output_file.write('LOCAL_EQUATIONS ') for i, constraint_data in enumerate(l_eqns): con_symbol = symbol_map.createSymbol(constraint_data, c_labeler) assert not con_symbol.startswith('.') assert con_symbol != "c_e_FIX_ONE_VAR_CONST__" symbol_map.alias(constraint_data, alias_template % order_counter) if i == n_leqns-1: output_file.write(str(con_symbol)+';\n\n') else: output_file.write(str(con_symbol)+', ') order_counter += 1 # Create a dictionary of baron variable names to match to the # strings that constraint.to_string() prints. An important # note is that the variable strings are padded by spaces so # that whole variable names are recognized, and simple # variable names are not identified inside longer names. # Example: ' x[1] ' -> ' x3 ' #FIXME: 7/18/14 CLH: This may cause mistakes if spaces in # variable names are allowed if isinstance(model, IBlock): mutable_param_gen = lambda b: \ b.components(ctype=Param, descend_into=False) else: def mutable_param_gen(b): for param in block.component_objects(Param): if param.mutable and param.is_indexed(): param_data_iter = \ (param_data for index, param_data in iteritems(param)) elif not param.is_indexed(): param_data_iter = iter([param]) else: param_data_iter = iter([]) for param_data in param_data_iter: yield param_data if False: # # This was part of a merge from master that caused # test failures. But commenting this out didn't cause additional failures!?! # vstring_to_var_dict = {} vstring_to_bar_dict = {} pstring_to_bar_dict = {} for block in all_blocks_list: for var_data in active_components_data_var[id(block)]: variable_stream = StringIO() var_data.to_string(ostream=variable_stream, verbose=False) variable_string = variable_stream.getvalue() variable_string = ' '+variable_string+' ' vstring_to_var_dict[variable_string] = var_data if output_fixed_variable_bounds or (not var_data.fixed): vstring_to_bar_dict[variable_string] = \ ' '+object_symbol_dictionary[id(var_data)]+' ' else: assert var_data.value is not None vstring_to_bar_dict[variable_string] = \ ftoa(var_data.value) for param_data in mutable_param_gen(block): param_stream = StringIO() param_data.to_string(ostream=param_stream, verbose=False) param_string = param_stream.getvalue() param_string = ' '+param_string+' ' pstring_to_bar_dict[param_string] = ftoa(param_data()) # Equation Definition output_file.write('c_e_FIX_ONE_VAR_CONST__: ONE_VAR_CONST__ == 1;\n'); for constraint_data in itertools.chain(eqns, r_o_eqns, c_eqns, l_eqns): variables = OrderedSet() #print(symbol_map.byObject.keys()) eqn_body = expression_to_string(constraint_data.body, variables, smap=symbol_map) #print(symbol_map.byObject.keys()) referenced_variable_ids.update(variables) if len(variables) == 0: assert not skip_trivial_constraints eqn_body += " + 0 * ONE_VAR_CONST__ " # 7/29/14 CLH: #FIXME: Baron doesn't handle many of the # intrinsic_functions available in pyomo. The # error message given by baron is also very # weak. Either a function here to re-write # unallowed expressions or a way to track solver # capability by intrinsic_expression would be # useful. ########################## con_symbol = symbol_map.byObject[id(constraint_data)] output_file.write(str(con_symbol) + ': ') # Fill in the left and right hand side (constants) of # the equations # Equality constraint if constraint_data.equality: eqn_lhs = '' eqn_rhs = ' == ' + ftoa(constraint_data.upper) # Greater than constraint elif not constraint_data.has_ub(): eqn_rhs = ' >= ' + ftoa(constraint_data.lower) eqn_lhs = '' # Less than constraint elif not constraint_data.has_lb(): eqn_rhs = ' <= ' + ftoa(constraint_data.upper) eqn_lhs = '' # Double-sided constraint elif constraint_data.has_lb() and \ constraint_data.has_ub(): eqn_lhs = ftoa(constraint_data.lower) + \ ' <= ' eqn_rhs = ' <= ' + ftoa(constraint_data.upper) eqn_string = eqn_lhs + eqn_body + eqn_rhs + ';\n' output_file.write(eqn_string) # # OBJECTIVE # output_file.write("\nOBJ: ") n_objs = 0 for block in all_blocks_list: for objective_data in block.component_data_objects(Objective, active=True, sort=sorter, descend_into=False): n_objs += 1 if n_objs > 1: raise ValueError("The BARON writer has detected multiple active " "objective functions on model %s, but " "currently only handles a single objective." % (model.name)) # create symbol symbol_map.createSymbol(objective_data, c_labeler) symbol_map.alias(objective_data, "__default_objective__") if objective_data.is_minimizing(): output_file.write("minimize ") else: output_file.write("maximize ") variables = OrderedSet() #print(symbol_map.byObject.keys()) obj_string = expression_to_string(objective_data.expr, variables, smap=symbol_map) #print(symbol_map.byObject.keys()) referenced_variable_ids.update(variables) output_file.write(obj_string+";\n\n") #referenced_variable_ids.update(symbol_map.byObject.keys()) return referenced_variable_ids, branching_priorities_suffixes def __call__(self, model, output_filename, solver_capability, io_options): # Make sure not to modify the user's dictionary, they may be # reusing it outside of this call io_options = dict(io_options) # NOTE: io_options is a simple dictionary of keyword-value # pairs specific to this writer. symbolic_solver_labels = \ io_options.pop("symbolic_solver_labels", False) labeler = io_options.pop("labeler", None) # How much effort do we want to put into ensuring the # LP file is written deterministically for a Pyomo model: # 0 : None # 1 : sort keys of indexed components (default) # 2 : sort keys AND sort names (over declaration order) file_determinism = io_options.pop("file_determinism", 1) sorter = SortComponents.unsorted if file_determinism >= 1: sorter = sorter | SortComponents.indices if file_determinism >= 2: sorter = sorter | SortComponents.alphabetical output_fixed_variable_bounds = \ io_options.pop("output_fixed_variable_bounds", False) # Skip writing constraints whose body section is fixed (i.e., # no variables) skip_trivial_constraints = \ io_options.pop("skip_trivial_constraints", False) # Note: Baron does not allow specification of runtime # option outside of this file, so we add support # for them here solver_options = io_options.pop("solver_options", {}) if len(io_options): raise ValueError( "ProblemWriter_baron_writer passed unrecognized io_options:\n\t" + "\n\t".join("%s = %s" % (k,v) for k,v in iteritems(io_options))) if symbolic_solver_labels and (labeler is not None): raise ValueError("Baron problem writer: Using both the " "'symbolic_solver_labels' and 'labeler' " "I/O options is forbidden") # Make sure there are no strange ActiveComponents. The expression # walker will handle strange things in constraints later. model_ctypes = model.collect_ctypes(active=True) invalids = set() for t in (model_ctypes - valid_active_ctypes_minlp): if issubclass(t, ActiveComponent): invalids.add(t) if len(invalids): invalids = [t.__name__ for t in invalids] raise RuntimeError( "Unallowable active component(s) %s.\nThe BARON writer cannot " "export models with this component type." % ", ".join(invalids)) if output_filename is None: output_filename = model.name + ".bar" output_file=open(output_filename, "w") # Process the options. Rely on baron to catch # and reset bad option values output_file.write("OPTIONS {\n") summary_found = False if len(solver_options): for key, val in iteritems(solver_options): if (key.lower() == 'summary'): summary_found = True if key.endswith("Name"): output_file.write(key+": \""+str(val)+"\";\n") else: output_file.write(key+": "+str(val)+";\n") if not summary_found: # The 'summary option is defaulted to 0, so that no # summary file is generated in the directory where the # user calls baron. Check if a user explicitly asked for # a summary file. output_file.write("Summary: 0;\n") output_file.write("}\n\n") if symbolic_solver_labels: # Note that the Var and Constraint labelers must use the # same labeler, so that we can correctly detect name # collisions (which can arise when we truncate the labels to # the max allowable length. BARON requires all identifiers # to start with a letter. We will (randomly) choose "s_" # (for 'shortened') v_labeler = c_labeler = ShortNameLabeler( 15, prefix='s_', suffix='_', caseInsensitive=True, legalRegex='^[a-zA-Z]') elif labeler is None: v_labeler = NumericLabeler('x') c_labeler = NumericLabeler('c') else: v_labeler = c_labeler = labeler symbol_map = SymbolMap() symbol_map.default_labeler = v_labeler #sm_bySymbol = symbol_map.bySymbol # Cache the list of model blocks so we don't have to call # model.block_data_objects() many many times, which is slow # for indexed blocks all_blocks_list = list(model.block_data_objects(active=True, sort=sorter, descend_into=True)) active_components_data_var = {} #for block in all_blocks_list: # tmp = active_components_data_var[id(block)] = \ # list(obj for obj in block.component_data_objects(Var, # sort=sorter, # descend_into=False)) # create_symbols_func(symbol_map, tmp, labeler) # GAH: Not sure this is necessary, and also it would break for # non-mutable indexed params so I am commenting out for now. #for param_data in active_components_data(block, Param, sort=sorter): #instead of checking if param_data.mutable: #if not param_data.is_constant(): # create_symbol_func(symbol_map, param_data, labeler) #symbol_map_variable_ids = set(symbol_map.byObject.keys()) #object_symbol_dictionary = symbol_map.byObject # # Go through the objectives and constraints and generate # the output so that we can obtain the set of referenced # variables. # equation_section_stream = StringIO() referenced_variable_ids, branching_priorities_suffixes = \ self._write_equations_section( model, equation_section_stream, all_blocks_list, active_components_data_var, symbol_map, c_labeler, output_fixed_variable_bounds, skip_trivial_constraints, sorter) # # BINARY_VARIABLES, INTEGER_VARIABLES, POSITIVE_VARIABLES, VARIABLES # BinVars = [] IntVars = [] PosVars = [] Vars = [] for vid in referenced_variable_ids: name = symbol_map.byObject[vid] var_data = symbol_map.bySymbol[name]() if var_data.is_continuous(): if var_data.has_lb() and (value(var_data.lb) >= 0): TypeList = PosVars else: TypeList = Vars elif var_data.is_binary(): TypeList = BinVars elif var_data.is_integer(): TypeList = IntVars else: assert False TypeList.append(name) if len(BinVars) > 0: BinVars.sort() output_file.write('BINARY_VARIABLES ') output_file.write(", ".join(BinVars)) output_file.write(';\n\n') if len(IntVars) > 0: IntVars.sort() output_file.write('INTEGER_VARIABLES ') output_file.write(", ".join(IntVars)) output_file.write(';\n\n') PosVars.append('ONE_VAR_CONST__') PosVars.sort() output_file.write('POSITIVE_VARIABLES ') output_file.write(", ".join(PosVars)) output_file.write(';\n\n') if len(Vars) > 0: Vars.sort() output_file.write('VARIABLES ') output_file.write(", ".join(Vars)) output_file.write(';\n\n') # # LOWER_BOUNDS # lbounds = {} for vid in referenced_variable_ids: name = symbol_map.byObject[vid] var_data = symbol_map.bySymbol[name]() if var_data.fixed: if output_fixed_variable_bounds: var_data_lb = ftoa(var_data.value) else: var_data_lb = None else: var_data_lb = None if var_data.has_lb(): var_data_lb = ftoa(var_data.lb) if var_data_lb is not None: name_to_output = symbol_map.getSymbol(var_data) lbounds[name_to_output] = '%s: %s;\n' % ( name_to_output, var_data_lb) if len(lbounds) > 0: output_file.write("LOWER_BOUNDS{\n") output_file.write("".join( lbounds[key] for key in sorted(lbounds.keys()) ) ) output_file.write("}\n\n") lbounds = None # # UPPER_BOUNDS # ubounds = {} for vid in referenced_variable_ids: name = symbol_map.byObject[vid] var_data = symbol_map.bySymbol[name]() if var_data.fixed: if output_fixed_variable_bounds: var_data_ub = ftoa(var_data.value) else: var_data_ub = None else: var_data_ub = None if var_data.has_ub(): var_data_ub = ftoa(var_data.ub) if var_data_ub is not None: name_to_output = symbol_map.getSymbol(var_data) ubounds[name_to_output] = '%s: %s;\n' % ( name_to_output, var_data_ub) if len(ubounds) > 0: output_file.write("UPPER_BOUNDS{\n") output_file.write("".join( ubounds[key] for key in sorted(ubounds.keys()) ) ) output_file.write("}\n\n") ubounds = None # # BRANCHING_PRIORITIES # # Specifying priorities requires that the pyomo model has established an # EXTERNAL, float suffix called 'branching_priorities' on the model # object, indexed by the relevant variable BranchingPriorityHeader = False for suffix in branching_priorities_suffixes: for var_data, priority in iteritems(suffix): if id(var_data) not in referenced_variable_ids: continue if priority is not None: if not BranchingPriorityHeader: output_file.write('BRANCHING_PRIORITIES{\n') BranchingPriorityHeader = True name_to_output = symbol_map.getSymbol(var_data) output_file.write(name_to_output+': '+str(priority)+';\n') if BranchingPriorityHeader: output_file.write("}\n\n") # # Now write the objective and equations section # output_file.write(equation_section_stream.getvalue()) # # STARTING_POINT # output_file.write('STARTING_POINT{\nONE_VAR_CONST__: 1;\n') tmp = {} for vid in referenced_variable_ids: name = symbol_map.byObject[vid] var_data = symbol_map.bySymbol[name]() starting_point = var_data.value if starting_point is not None: var_name = symbol_map.getSymbol(var_data) tmp[var_name] = "%s: %s;\n" % ( var_name, ftoa(starting_point)) output_file.write("".join( tmp[key] for key in sorted(tmp.keys()) )) output_file.write('}\n\n') output_file.close() return output_filename, symbol_map