CDPL.Chem.AtomMatchExpression Class Reference

A generic boolean expression interface for the implementation of query/target object equivalence tests in molecular graph matching algorithms. More...

Inheritance diagram for CDPL.Chem.AtomMatchExpression:

Public Member Functions
None	__init__ ()
	Initializes the AtomMatchExpression instance.
int	getObjectID ()
	Returns the numeric identifier (ID) of the wrapped C++ class instance. More...
bool	requiresAtomBondMapping ()
	Tells whether the expression must be reevaluated after a query to target atom/bond mapping candidate has been found. More...
bool	__call__ (Atom query_atom, MolecularGraph query_molgraph, Atom target_atom, MolecularGraph target_molgraph, Base.Any aux_data)
	Performs an evaluation of the expression for the given query and target objects. More...
bool	__call__ (Atom query_atom, MolecularGraph query_molgraph, Atom target_atom, MolecularGraph target_molgraph, AtomBondMapping mapping, Base.Any aux_data)
	Performs an evaluation of the expression for the given query and target objects under consideration of the provided candidate atom/bond mapping. More...

Properties
	objectID = property(getObjectID)

Detailed Description

A generic boolean expression interface for the implementation of query/target object equivalence tests in molecular graph matching algorithms.

The AtomMatchExpression interface abstracts the task of checking a set of constraints on the attributes of target objects when performing query object equivalence tests in molecular graph matching procedures. Subclasses of AtomMatchExpression must override one (or all, if required) of the provided function call operators to implement the logic of the constraint checks. The first form of the two operators gets called in the pre-mapping stage of the graph matching algorithm where all feasible query/target object pairings are determined. In this pre-mapping stage all sorts of query constraints can be checked that are invariant with respect to the final mapping between any of the other query and target objects. The second type of operator is invoked immediately after a complete graph mapping solution has been found and can be used to re-evaluate the validity of a given query/target object pairing in the context of the provided matching result. As soon as a pairing is found to be invalid, the current mapping solution is rejected and the algorithm proceeds to find the next possible query to target graph mapping (if any). For efficiency reasons, subclasses of AtomMatchExpression which implement the post-mapping function call operator must explicitly enable its invocation by additionally overriding the AtomMatchExpression.requiresAtomBondMapping() method. Its implementation simply has to return True (the default implementation returns False) to request the invocation of the operator.

Member Function Documentation

getObjectID()

int CDPL.Chem.AtomMatchExpression.getObjectID

(

)

Returns the numeric identifier (ID) of the wrapped C++ class instance.

Different Python AtomMatchExpression instances may reference the same underlying C++ class instance. The commonly used Python expression a is not b thus cannot tell reliably whether the two AtomMatchExpression instances a and b reference different C++ objects. The numeric identifier returned by this method allows to correctly implement such an identity test via the simple expression a.getObjectID() != b.getObjectID().

Returns

The numeric ID of the internally referenced C++ class instance.

Reimplemented in CDPL.Chem.AtomMatchExpressionList.

requiresAtomBondMapping()

bool CDPL.Chem.AtomMatchExpression.requiresAtomBondMapping

(

)

Tells whether the expression must be reevaluated after a query to target atom/bond mapping candidate has been found.

Returns

True if the expression needs to be evaluated again after a query to target atom/bond mapping candidate has been found, and False otherwise.

Note

The default implementation returns False.

__call__() [1/2]

bool CDPL.Chem.AtomMatchExpression.__call__	(	Atom	query_atom,
		MolecularGraph	query_molgraph,
		Atom	target_atom,
		MolecularGraph	target_molgraph,
		Base.Any	aux_data
	)

Performs an evaluation of the expression for the given query and target objects.

Parameters

query_atom	The query atom.
query_molgraph	The query molecular graph.
target_atom	The target atom.
target_molgraph	The target molecular graph.
aux_data	Provides auxiliary information for the evaluation of the expression.

Returns

The result of the expression evaluation for the specified query and target objects.

Note

The default implementation returns True.

__call__() [2/2]

bool CDPL.Chem.AtomMatchExpression.__call__	(	Atom	query_atom,
		MolecularGraph	query_molgraph,
		Atom	target_atom,
		MolecularGraph	target_molgraph,
		AtomBondMapping	mapping,
		Base.Any	aux_data
	)

Performs an evaluation of the expression for the given query and target objects under consideration of the provided candidate atom/bond mapping.

Parameters

query_atom	The query atom.
query_molgraph	The query molecular graph.
target_atom	The target atom.
target_molgraph	The target molecular graph.
mapping	The current query to target atom/bond mapping candidate to evaluate.
aux_data	Provides auxiliary information for the evaluation of the expression.

Returns

The result of the expression evaluation for the specified query and target objects.

Note

The default implementation returns the result of call(query_atom, query_molgraph, target_atom, target_molgraph, aux_data).