`alogos.systems.cfggpst.mapping`¶

Forward and reverse mapping functions for CFG-GP-ST.

Functions¶

`forward`(grammar, genotype, parameters=None, raise_errors=True, return_derivation_tree=False, verbose=False)	Map a CFG-GP-ST genotype to a string phenotype.
`reverse`(grammar, phenotype_or_derivation_tree, parameters=None, return_derivation_tree=False)	Map a string phenotype (or derivation tree) to a CFG-GP-ST genotype.

Detailed object descriptions¶

alogos.systems.cfggpst.mapping.forward(grammar, genotype, parameters=None, raise_errors=True, return_derivation_tree=False, verbose=False)[source]¶

Map a CFG-GP-ST genotype to a string phenotype.

Parameters:

grammar (Grammar)
genotype (Genotype or data that can be converted to it)
parameters (dict or ParameterCollection, optional) – No keyword-value pairs are considered by this function. This argument is only available to have a consistent interface.
raise_errors (bool, optional) – Possible values:
- True: A mapping error will be raised if a derivation is not finished within a limit provided in the parameters.
- False: A partial derivation is allowed. In this case, the returned string will contain unexpanded nonterminal symbols. Therefore it is not a valid phenotype, i.e. not a string of the grammar’s language but a so-called sentential form.
return_derivation_tree (bool, optional) – If True, not only the phenotype is returned but additionally also the derivation tree.
verbose (bool, optional) – If True, output about steps of the mapping process is printed.

Returns:

phenotype (str) – If return_derivation_tree is False, which is the default.
(phenotype, derivation_tree) (tuple with two elements of type str and DerivationTree) – If return_derivation_tree is True.

Raises:

MappingError – If raise_errors is True and the mapping process can not generate a full derivation before reaching a limit provided in the parameters.

alogos.systems.cfggpst.mapping.reverse(grammar, phenotype_or_derivation_tree, parameters=None, return_derivation_tree=False)[source]¶

Map a string phenotype (or derivation tree) to a CFG-GP-ST genotype.