Merge pull request #3695 from michaelbynum/observer

Model Observer

Author: michaelbynum

pyomo/contrib/observer/__init__.py

@@ -0,0 +1,10 @@
+#  ___________________________________________________________________________
+#
+#  Pyomo: Python Optimization Modeling Objects
+#  Copyright (c) 2008-2025
+#  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.
+#  ___________________________________________________________________________

pyomo/contrib/observer/component_collector.py

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+#  ___________________________________________________________________________
+#
+#  Pyomo: Python Optimization Modeling Objects
+#  Copyright (c) 2008-2025
+#  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.
+#  ___________________________________________________________________________
+
+from pyomo.core.expr.visitor import StreamBasedExpressionVisitor
+from pyomo.core.expr.numeric_expr import (
+    ExternalFunctionExpression,
+    NegationExpression,
+    PowExpression,
+    MaxExpression,
+    MinExpression,
+    ProductExpression,
+    MonomialTermExpression,
+    DivisionExpression,
+    SumExpression,
+    Expr_ifExpression,
+    UnaryFunctionExpression,
+    AbsExpression,
+)
+from pyomo.core.expr.relational_expr import (
+    RangedExpression,
+    InequalityExpression,
+    EqualityExpression,
+)
+from pyomo.core.base.var import VarData, ScalarVar
+from pyomo.core.base.param import ParamData, ScalarParam
+from pyomo.core.base.expression import ExpressionData, ScalarExpression
+from pyomo.repn.util import ExitNodeDispatcher
+from pyomo.common.collections import ComponentSet
+
+
+def handle_var(node, collector):
+    collector.variables.add(node)
+    return None
+
+
+def handle_param(node, collector):
+    collector.params.add(node)
+    return None
+
+
+def handle_named_expression(node, collector):
+    collector.named_expressions.add(node)
+    return None
+
+
+def handle_external_function(node, collector):
+    collector.external_functions.add(node)
+    return None
+
+
+def handle_skip(node, collector):
+    return None
+
+
+collector_handlers = ExitNodeDispatcher()
+collector_handlers[VarData] = handle_var
+collector_handlers[ParamData] = handle_param
+collector_handlers[ExpressionData] = handle_named_expression
+collector_handlers[ScalarExpression] = handle_named_expression
+collector_handlers[ExternalFunctionExpression] = handle_external_function
+collector_handlers[NegationExpression] = handle_skip
+collector_handlers[PowExpression] = handle_skip
+collector_handlers[MaxExpression] = handle_skip
+collector_handlers[MinExpression] = handle_skip
+collector_handlers[ProductExpression] = handle_skip
+collector_handlers[MonomialTermExpression] = handle_skip
+collector_handlers[DivisionExpression] = handle_skip
+collector_handlers[SumExpression] = handle_skip
+collector_handlers[Expr_ifExpression] = handle_skip
+collector_handlers[UnaryFunctionExpression] = handle_skip
+collector_handlers[AbsExpression] = handle_skip
+collector_handlers[RangedExpression] = handle_skip
+collector_handlers[InequalityExpression] = handle_skip
+collector_handlers[EqualityExpression] = handle_skip
+collector_handlers[int] = handle_skip
+collector_handlers[float] = handle_skip
+
+
+class _ComponentFromExprCollector(StreamBasedExpressionVisitor):
+    def __init__(self, **kwds):
+        self.named_expressions = ComponentSet()
+        self.variables = ComponentSet()
+        self.params = ComponentSet()
+        self.external_functions = ComponentSet()
+        super().__init__(**kwds)
+
+    def exitNode(self, node, data):
+        return collector_handlers[node.__class__](node, self)
+
+    def beforeChild(self, node, child, child_idx):
+        if child in self.named_expressions:
+            return False, None
+        return True, None
+
+
+_visitor = _ComponentFromExprCollector()
+
+
+def collect_components_from_expr(expr):
+    _visitor.__init__()
+    _visitor.walk_expression(expr)
+    return (
+        _visitor.named_expressions,
+        _visitor.variables,
+        _visitor.params,
+        _visitor.external_functions,
+    )