Preliminary implementation of outer approximation and partial surrogate cuts in Pyomo

pyomo/core/base/component.py

@@ -541,6 +541,8 @@ class ComponentData(_ComponentBase):
     __pickle_slots__ = ('_component',)
     __slots__ = __pickle_slots__ + ('__weakref__',)
 
+    labeler = []
+
     def __init__(self, owner):
         #
         # ComponentData objects are typically *private* objects for
@@ -685,7 +687,10 @@ def to_string(self, ostream=None, verbose=None, precedence=0):
         """Write the component name and index to a buffer"""
         if ostream is None:
             ostream = sys.stdout
-        ostream.write(self.__str__())
+        if not ComponentData.labeler:
+            ostream.write(self.__str__())
+        else:
+            ostream.write(ComponentData.labeler[-1](self))
 
     def getname(self, fully_qualified=False, name_buffer=None):
         """Return a string with the component name and index"""

pyomo/core/base/label.py

@@ -9,13 +9,15 @@
 #  ___________________________________________________________________________
 
 __all__ = ['CounterLabeler', 'NumericLabeler', 'CNameLabeler', 'TextLabeler',
-           'AlphaNumTextLabeler','NameLabeler', 'CuidLabeler']
+           'AlphaNumericTextLabeler','NameLabeler', 'CuidLabeler']
 
 import six
 if six.PY3:
-    _string = str
+    _translate = str.translate
 else:
-    import string as _string
+    import string
+    _translate = string.translate
+
 from pyomo.core.base.component import ComponentUID
 
 # This module provides some basic functionality for generating labels
@@ -24,30 +26,64 @@
 # optimization input file formats, e.g., CPLEX LP files.  The purpose of
 # this module is to provide a simple remap function, that will satisfy
 # broadly problematic symbols. if solver-specific remaps are required,
-# they should be handled either in the corresponding solver plugin.
-
-# NOTE: Simple single-character substitutions should be handled by adding
-#       to the translation table constructed below - first argument is the
-#       "from" characters, second argument is the "to" characters.
-cpxlp_translation_table = _string.maketrans("[]{} -#$%&*+.,/;<=>?@^!~':",
-                                             "()()______________________")
+# they should be handled in the corresponding solver plugin.
+
+class _CharMapper(object):
+    def __init__(self, preserve, translate, other):
+        """
+        Arguments::
+           preserve: a string of characters to preserve
+           translate: a dict or key/value list of characters to translate
+           other: the character to return for all characters not in
+                  preserve or translate
+        """
+        self.table = dict(
+            (k if isinstance(k, int) else ord(k), v)
+            for k,v in six.iteritems(dict(translate)) )
+        for c in preserve:
+            _c = ord(c)
+            if _c in self.table and self.table[_c] != c:
+                raise RuntimeError("Duplicate character '%s' appears in both "
+                                   "translate table and preserve list" % (c,))
+            self.table[_c] = c
+        self.other = other
+
+    def __getitem__(self, c):
+        # Most of the time c should be known.  For the rare cases we
+        # encounter a new character, remember it by adding a new entry
+        # into the translation table and return the default character
+        try:
+            return self.table[c]
+        except:
+            self.table[c] = self.other
+            return self.other
+
+    def make_table(self):
+        return ''.join(self[i] for i in range(256))
+
+_alpha = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJLKMNOPQRSTUVWXYZ'
+_digit = '1234567890'
+_cpxlp_translation_table = _CharMapper( preserve=_alpha+_digit+'()_',
+                                        translate = zip('[]{}', '()()'),
+                                        other='_' ).make_table()
 def cpxlp_label_from_name(name):
 
     if name is None:
         raise RuntimeError("Illegal name=None supplied to "
                            "cpxlp_label_from_name function")
 
-    return _string.translate(name, cpxlp_translation_table)
+    return _translate(name, _cpxlp_translation_table)
 
-alphanum_translation_table = _string.maketrans("()[]{} -#$%&*+.,/;<=>?@^!~':",
-                                               "____________________________")
+_alphanum_translation_table = _CharMapper( preserve=_alpha+_digit+'_',
+                                       translate = {},
+                                       other='_' ).make_table()
 def alphanum_label_from_name(name):
 
     if name is None:
         raise RuntimeError("Illegal name=None supplied to "
                            "alphanum_label_from_name function")
 
-    return _string.translate(name, alphanum_translation_table)
+    return _translate(name, _alphanum_translation_table)
 
 class CuidLabeler(object):
 
@@ -95,7 +131,7 @@ def __init__(self):
     def __call__(self, obj):
         return cpxlp_label_from_name(obj.getname(True, self.name_buffer))
 
-class AlphaNumTextLabeler(object):
+class AlphaNumericTextLabeler(object):
     def __init__(self):
         self.name_buffer = {}
 

pyomo/opt/base/formats.py

@@ -29,8 +29,9 @@
 #                   pyomo.opt.colin.OptProblem (this can wrap a COLIN shell
 #                   command, or provide a runtime optimization problem)
 # bar - A Baron input file
+# gams - A GAMS input file
 #
-ProblemFormat = Enum('colin', 'pyomo', 'cpxlp', 'nl', 'mps', 'mod', 'lpxlp', 'osil', 'colin_optproblem', 'FuncDesigner','bar')
+ProblemFormat = Enum('colin', 'pyomo', 'cpxlp', 'nl', 'mps', 'mod', 'lpxlp', 'osil', 'colin_optproblem', 'FuncDesigner','bar','gams')
 
 #
 # osrl - osrl XML file defined by the COIN-OR OS project: Result
@@ -52,6 +53,9 @@ def guess_format(filename):
     formats['mod']=ProblemFormat.mod
     formats['lp']=ProblemFormat.cpxlp
     formats['osil']=ProblemFormat.osil
+    formats['gms']=ProblemFormat.gams
+    formats['gams']=ProblemFormat.gams
+
     formats['sol']=ResultsFormat.sol
     formats['osrl']=ResultsFormat.osrl
     formats['soln']=ResultsFormat.soln
@@ -60,7 +64,7 @@ def guess_format(filename):
     formats['jsn']=ResultsFormat.json
     formats['json']=ResultsFormat.json
     formats['results']=ResultsFormat.yaml
-    for fmt in formats:
-        if filename.endswith('.'+fmt):
-            return formats[fmt]
-    return None
+    if filename:
+        return formats.get(filename.split('.')[-1].strip(), None)
+    else:
+        return None

pyomo/repn/canonical_repn.py

@@ -2,8 +2,8 @@
 #
 #  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 
+#  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.
 #  ___________________________________________________________________________
@@ -26,14 +26,17 @@
                                         SimpleExpression,
                                         Expression)
 from pyomo.core.base.objective import (_GeneralObjectiveData,
-                                       SimpleObjective)
+                                       SimpleObjective,
+                                       _ObjectiveData)
 from pyomo.core.base.connector import (_ConnectorData,
                                        SimpleConnector,
                                        Connector)
 from pyomo.core.base.var import (SimpleVar,
                                  Var,
                                  _GeneralVarData,
                                  _VarData)
+from pyomo.core.kernel.component_objective import IObjective
+from pyomo.core.base.numvalue import NumericConstant
 
 from pyomo.core.base import expr_pyomo4
 from pyomo.core.base import expr_coopr3
@@ -751,6 +754,7 @@ def _collect_identity(exp, idMap, multiplier, coef, varmap, compute_values):
     param.SimpleParam       : _collect_linear_const,
     param.Param             : _collect_linear_const,
     parameter               : _collect_linear_const,
+    NumericConstant         : _collect_linear_const,
     _GeneralVarData         : _collect_linear_var,
     SimpleVar               : _collect_linear_var,
     Var                     : _collect_linear_var,
@@ -773,7 +777,7 @@ def _get_linear_collector(exp, idMap, multiplier,
         if isinstance(exp, (_VarData, IVariable)):
             _collect_linear_var(exp, idMap, multiplier,
                                 coef, varmap, compute_values)
-        elif isinstance(exp, (param._ParamData, IParameter)):
+        elif isinstance(exp, (param._ParamData, IParameter, NumericConstant)):
             _collect_linear_const(exp, idMap, multiplier,
                                   coef, varmap, compute_values)
         elif isinstance(exp, (_ExpressionData, IIdentityExpression)):

pyomo/repn/plugins/__init__.py

@@ -13,4 +13,5 @@ def load():
     import pyomo.repn.plugins.ampl
     import pyomo.repn.plugins.baron_writer
     import pyomo.repn.plugins.mps
+    import pyomo.repn.plugins.gams_writer