alogos.exceptions

All custom exceptions used in the package.

Detailed object descriptions

exception alogos.exceptions.GrammarError[source]

Bases: Exception

Raised when a grammar can not be read, written or is ill-formed.

Examples

  • The set of nonterminal symbols, terminal symbols or production rules is empty.

  • A nonterminal symbol has no production rule where its right-hand side is defined.

exception alogos.exceptions.ParserError[source]

Bases: Exception

Raised when parsing a string with a grammar fails.

Examples

  • The string contains characters that are not part of any terminal symbol.

  • The string does not belong to the language of the given grammar.

  • The chosen parser is not compatible with the given grammar.

exception alogos.exceptions.ParameterError[source]

Bases: Exception

Raised when a parameter or collection of parameters is invalid.

Examples

  • An unknown parameter is provided or requested by a user.

  • All variation operators of an evolutionary algorithm are turned off.

  • All stop criteria of a search algorithm are inactive.

exception alogos.exceptions.GenotypeError[source]

Bases: Exception

Raised when a genotype is not well-formed or modified.

Examples

  • The genotype can not be interpreted as a list of integers for Grammatical Evolution (GE).

  • The genotype can not be interpreted as a derivation tree for Context-Free Grammar Genetic Programming (CFGGP).

  • A user tries to modify the immutable genotype attribute of an individual.

exception alogos.exceptions.InitializationError[source]

Bases: Exception

Raised when intitialization of an individual or population fails.

Examples

  • A user-provided genotype is not well-formed.

  • A user-provided phenotype can not be parsed and reverse mapped to a genotype.

exception alogos.exceptions.OperatorError[source]

Bases: Exception

Raised when a search operator fails.

Examples

  • A crossover operator that requires two parent genotypes of equal length fails because it gets two individuals with different genotype lengths as input.

exception alogos.exceptions.MappingError[source]

Bases: Exception

Raised when a genotype-to-phenotype mapping or its inverse fails.

Examples

  • Forward mapping: No string of terminals could be found within the allowed number of expansions or wrappings.

  • Reverse mapping: The provided grammar contains no production rule that would match a production found in a given derivation tree.

exception alogos.exceptions.DatabaseError[source]

Bases: Exception

Raised when storing or retrieving data from a database fails.

Examples

  • The provided filepath does not point to a valid file-based database.

  • There is no database entry that matches to a user-provided value.