neurolang.exceptions#

Exceptions

`CouldNotTranslateConjunctionException`(output)	This conjunctive formula could not be translated into an equivalent relational algebra representation.
`ForbiddenBuiltinError`
`ForbiddenDisjunctionError`	Probabilistic queries do not support disjunctions.
`ForbiddenExistentialError`
`ForbiddenExpressionError`	Generic exception specifying an error in the program.
`ForbiddenRecursivityError`	The given program cannot be stratified due to recursivity.
`ForbiddenUnstratifiedAggregation`	The given Datalog program is not valid for aggregation.
`InvalidCommandExpression`	Invalid Command statement.
`NegativeFormulaNotNamedRelationException`(formula)	This rule contains a negative literal R(v) which was not previously defined as a non-negated relation.
`NegativeFormulaNotSafeRangeException`(formula)	This rule is not range restricted and cannot be solved in nonrecursive datalog with negation.
`NeuroLangException`	Base class for NeuroLang Exceptions
`NeuroLangFrontendException`
`NeuroLangNotImplementedError`
`NoValidChaseClassForStratumException`	Neurolang implements stratified datalog which splits a datalog program into several independent strata that can each be solved by a specific chase algorithm based on the properties of the rules in the stratum (using negation, aggregation and/or recursion).
`NonLiftableException`
`NotConjunctiveExpression`	This expression is not conjunctive.
`NotConjunctiveExpressionNegation`	This expression is not conjunctive.
`NotConjunctiveExpressionNestedPredicates`	This expression is not conjunctive.
`NotInFONegE`
`NotRankedException`
`NotUnateException`
`ParserError`(message[, line, column])
`ProjectionOverMissingColumnsError`	One of the predicates in the program has wrong arguments.
`ProtectedKeywordError`	One of the predicates in the program uses a reserved keyword.
`RelationalAlgebraError`	Base class for Relational Algebra provenance exceptions.
`RelationalAlgebraNotImplementedError`	Neurolang was unable to match one of the relational algebra operations defined in the program.
`RuleNotFoundError`
`SquallSemanticError`(message, *[, line, ...])	Semantic error in a SQUALL program — parse succeeded but semantics invalid.
`SymbolNotFoundError`	A symbol is being used in a rule without having been previously defined.
`TranslateToNamedRAException`	Base exception for errors translating Datalog to Named Relational Algebra.
`UnexpectedCharactersError`(message[, line, ...])
`UnexpectedExpressionError`
`UnexpectedTokenError`(message[, line, column])
`UnsupportedProgramError`	Some parts of the datalog program are (currently) unsupported.
`UnsupportedQueryError`	Queries on probabilistic predicates are unsupported.
`UnsupportedSolverError`
`WrongArgumentsInPredicateError`	One of the predicates in the query has the wrong number of arguments.

exception neurolang.exceptions.CouldNotTranslateConjunctionException(output)#

This conjunctive formula could not be translated into an equivalent relational algebra representation. This is probably because the formula is not in modified relational algebra normal form.

Generally speaking, the formula must be expressed in conjunctive normal form (CNF) or disjunctive normal form (DNF): as either a conjunction of disjunctions or disjunction of conjunctions.

See 5.4.7 from [1].

Examples

PositiveReverseInferenceSegregationQuery(
    t, n, PROB(t, n)
) :- (TopicAssociation(t, s) // SelectedStudy(s)) // (
    StudyMatchingNetworkQuery(s, n) & SelectedStudy(s)
)

This formula is not in DNF since it is a disjunction of a disjunction (TopicAssociation(t, s) // SelectedStudy(s)) and a conjunction (StudyMatchingNetworkQuery(s, n) & SelectedStudy(s)). A valid query would be:

PositiveReverseInferenceSegregationQuery(
    t, n, PROB(t, n)
) :- (TopicAssociation(t, s) & SelectedStudy(s)) // (
    StudyMatchingNetworkQuery(s, n) & SelectedStudy(s)
)

[1]

S. Abiteboul, R. Hull, V. Vianu, Foundations of databases (Addison Wesley, 1995), Addison-Wesley.

add_note()#: Exception.add_note(note) – add a note to the exception

with_traceback()#: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

exception neurolang.exceptions.ForbiddenBuiltinError#

add_note()#: Exception.add_note(note) – add a note to the exception

with_traceback()#: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

exception neurolang.exceptions.ForbiddenDisjunctionError#

Probabilistic queries do not support disjunctions.

A probabilistic choice can be added for a predicate symbol by using the add_probabilistic_choice_from_tuples method of a probabilistic Neurolang engine. But you cannot add multiple probabilistic facts or rule for the same predicate.

Examples

ProbActivation(r, PROB(r)) :- RegionReported(r, s) & SelectedStudy(s) ProbActivation(r, PROB(r)) :- ~RegionReported(r, s) & SelectedStudy(s)

This example program adds a disjunction of probabilistic queries which is not allowed.

add_note()#: Exception.add_note(note) – add a note to the exception

with_traceback()#: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

exception neurolang.exceptions.ForbiddenExistentialError#

add_note()#: Exception.add_note(note) – add a note to the exception

with_traceback()#: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

exception neurolang.exceptions.ForbiddenExpressionError#

Generic exception specifying an error in the program.

add_note()#: Exception.add_note(note) – add a note to the exception

with_traceback()#: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

exception neurolang.exceptions.ForbiddenRecursivityError#

The given program cannot be stratified due to recursivity.

When using probabilistic queries, a query can be solved through stratification if the probabilistic and deterministic parts are well separated. In case there exists one within-language probabilistic query dependency, no probabilistic predicate should appear in the stratum that depends on the query. The same holds for aggregate or negated queries. If a rule contains an aggregate or negated term, all the predicates in the body of the rule must be computed in a previous stratum.

Examples

B(x) :- A(x), C(x) A(x) :- B(x)

This program cannot be stratified because it contains a loop in the dependencies of each rule. Rule B(x) :- A(x), C(x) depends on the second rule through its occurrence of the predicate A(x). But rule A(x) :- B(x) in turn depends on the first rule through the B(x) predicate.

add_note()#: Exception.add_note(note) – add a note to the exception

with_traceback()#: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

exception neurolang.exceptions.ForbiddenUnstratifiedAggregation#

The given Datalog program is not valid for aggregation. Support for aggregation is done according to section 2.4.1 of [1].

A program is valid for aggregation if it can be stratified into strata P1, … , Pn such that, if A :- …,B,… is a rule in P such that A contains an aggregate term, and A is in stratum Pi while B is in stratum Pj, then i > j.

In other terms, all the predicates in the body of a rule containing an aggregate function must be computed in a previous stratum. Recursion through aggregation is therefore not allowed in the same stratum.

Examples

The following datalog program is invalid for stratified aggregation p(X) :- q(X). p(sum<X>) :- p(X).

[1]

T. J. Green, S. S. Huang, B. T. Loo, W. Zhou, Datalog and Recursive Query Processing. FNT in Databases. 5, 105–195 (2012).

add_note()#: Exception.add_note(note) – add a note to the exception

with_traceback()#: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

exception neurolang.exceptions.InvalidCommandExpression#

Invalid Command statement.

add_note()#: Exception.add_note(note) – add a note to the exception

with_traceback()#: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

exception neurolang.exceptions.NegativeFormulaNotNamedRelationException(formula)#

This rule contains a negative literal R(v) which was not previously defined as a non-negated relation.

Examples

t(x, y) :- r(x, y) & q(y, z) s(x, y, prob(x, y)) :- ~t(x, x) & q(x, y)

add_note()#: Exception.add_note(note) – add a note to the exception

with_traceback()#: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

exception neurolang.exceptions.NegativeFormulaNotSafeRangeException(formula)#

This rule is not range restricted and cannot be solved in nonrecursive datalog with negation. One of the variables in this rule appears in a negated literal without also appearing in a non-negated literal.

A datalog rule composed of literals of the form R(v) or ¬R(v) is range restricted if each variable x occurring in the rule occurs in at least one literal of the form R(v) (non-negated literal) in the rule body. See 5.2 from [1].

Examples

StudyNotMatchingSegregationQuery(s, n) :- (
    ~StudyMatchingNetworkQuery(s, n)
    & Network(n)
)

Variable s is present in the negated StudyMatchingNetworkQuery literal but is not present in a non-negated literal. A valid query body would be:

StudyNotMatchingSegregationQuery(s, n) :- (
    ~StudyMatchingNetworkQuery(s, n)
    & Study(s) & Network(n)
)

[1]

S. Abiteboul, R. Hull, V. Vianu, Foundations of databases (Addison Wesley, 1995), Addison-Wesley.

add_note()#: Exception.add_note(note) – add a note to the exception

with_traceback()#: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

exception neurolang.exceptions.NeuroLangException#

Base class for NeuroLang Exceptions

add_note()#: Exception.add_note(note) – add a note to the exception

with_traceback()#: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

exception neurolang.exceptions.NeuroLangFrontendException#

add_note()#: Exception.add_note(note) – add a note to the exception

with_traceback()#: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

exception neurolang.exceptions.NeuroLangNotImplementedError#

add_note()#: Exception.add_note(note) – add a note to the exception

with_traceback()#: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

exception neurolang.exceptions.NoValidChaseClassForStratumException#

Neurolang implements stratified datalog which splits a datalog program into several independent strata that can each be solved by a specific chase algorithm based on the properties of the rules in the stratum (using negation, aggregation and/or recursion).

This exception is raised if there is no valid algorithm available to solve a specific stratum; e.g. no recursive compatible algorithm was provided to solve a recursive stratum.

See neurolang.datalog.chase.__init__.py for available chase implementations.

add_note()#: Exception.add_note(note) – add a note to the exception

with_traceback()#: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

exception neurolang.exceptions.NonLiftableException#

add_note()#: Exception.add_note(note) – add a note to the exception

with_traceback()#: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

exception neurolang.exceptions.NotConjunctiveExpression#

This expression is not conjunctive. In this case, an expression is conjunctive if it is a conjunction of:

Constant
A function or predicate of constants

add_note()#: Exception.add_note(note) – add a note to the exception

with_traceback()#: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

exception neurolang.exceptions.NotConjunctiveExpressionNegation#

This expression is not conjunctive. In this case, an expression is conjunctive if it is a conjunction of:

Constant
A function or predicate of conjunctive arguments
A negated predicate of conjunctive arguments

add_note()#: Exception.add_note(note) – add a note to the exception

with_traceback()#: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

exception neurolang.exceptions.NotConjunctiveExpressionNestedPredicates#

This expression is not conjunctive. In this case, an expression is conjunctive if it is a conjunction of:

Constant
A function or predicate of conjunctive arguments
A quantifier of conjunctive arguments

Note that in this case, negated predicates are not valid (negation and aggregation cannot be used in the same rule).

Examples

StudyMatchingRegionSegregationQuery(count(s), r) :-: RegionReported(r, s) & ~RegionReported(r2, s) & RegionLabel(r2) & (r2 != r)

The above expression is not conjunctive since it uses an aggregate function count in combination with a negated predicate ~RegionReported.

add_note()#: Exception.add_note(note) – add a note to the exception

with_traceback()#: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

exception neurolang.exceptions.NotInFONegE#

add_note()#: Exception.add_note(note) – add a note to the exception

with_traceback()#: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

exception neurolang.exceptions.NotRankedException#

add_note()#: Exception.add_note(note) – add a note to the exception

with_traceback()#: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

exception neurolang.exceptions.NotUnateException#

add_note()#: Exception.add_note(note) – add a note to the exception

with_traceback()#: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

exception neurolang.exceptions.ParserError(message, line=None, column=None)#

add_note()#: Exception.add_note(note) – add a note to the exception

with_traceback()#: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

exception neurolang.exceptions.ProjectionOverMissingColumnsError#

One of the predicates in the program has wrong arguments. See WrongArgumentsInPredicateError

add_note()#: Exception.add_note(note) – add a note to the exception

with_traceback()#: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

exception neurolang.exceptions.ProtectedKeywordError#

One of the predicates in the program uses a reserved keyword. Reserved keywords include : {PROB, with, exists}

add_note()#: Exception.add_note(note) – add a note to the exception

with_traceback()#: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

exception neurolang.exceptions.RelationalAlgebraError#

Base class for Relational Algebra provenance exceptions.

add_note()#: Exception.add_note(note) – add a note to the exception

with_traceback()#: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

exception neurolang.exceptions.RelationalAlgebraNotImplementedError#

Neurolang was unable to match one of the relational algebra operations defined in the program. This is probably due to a malformed query.

add_note()#: Exception.add_note(note) – add a note to the exception

with_traceback()#: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

exception neurolang.exceptions.RuleNotFoundError#

add_note()#: Exception.add_note(note) – add a note to the exception

with_traceback()#: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

exception neurolang.exceptions.SquallSemanticError(message, *, line=None, column=None, source_line=None)#

Semantic error in a SQUALL program — parse succeeded but semantics invalid.

Raised when the SQUALL transformer encounters a valid parse tree that represents a logically invalid or unsupported construction, such as: - a rule with an empty body - an anaphoric the Noun with no matching for every Noun in scope - an unrecognised comparison or aggregation function - a missing determiner or noun group in a rule body

Parameters:

messagestr: Human-readable description of the error.
lineint, optional: 1-based source line number where the error was detected.
columnint, optional: 1-based source column number where the error was detected.
source_linestr, optional: The full source line text for context display.

add_note()#: Exception.add_note(note) – add a note to the exception

with_traceback()#: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

exception neurolang.exceptions.SymbolNotFoundError#

A symbol is being used in a rule without having been previously defined.

add_note()#: Exception.add_note(note) – add a note to the exception

with_traceback()#: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

exception neurolang.exceptions.TranslateToNamedRAException#

Base exception for errors translating Datalog to Named Relational Algebra.

add_note()#: Exception.add_note(note) – add a note to the exception

with_traceback()#: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

exception neurolang.exceptions.UnexpectedCharactersError(message, line=None, column=None)#

add_note()#: Exception.add_note(note) – add a note to the exception

with_traceback()#: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

exception neurolang.exceptions.UnexpectedExpressionError#

add_note()#: Exception.add_note(note) – add a note to the exception

with_traceback()#: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

exception neurolang.exceptions.UnexpectedTokenError(message, line=None, column=None)#

add_note()#: Exception.add_note(note) – add a note to the exception

with_traceback()#: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

exception neurolang.exceptions.UnsupportedProgramError#

Some parts of the datalog program are (currently) unsupported.

add_note()#: Exception.add_note(note) – add a note to the exception

with_traceback()#: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

exception neurolang.exceptions.UnsupportedQueryError#

Queries on probabilistic predicates are unsupported.

add_note()#: Exception.add_note(note) – add a note to the exception

with_traceback()#: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

exception neurolang.exceptions.UnsupportedSolverError#

add_note()#: Exception.add_note(note) – add a note to the exception

with_traceback()#: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.

exception neurolang.exceptions.WrongArgumentsInPredicateError#

One of the predicates in the query has the wrong number of arguments.

Examples

NetworkReported is defined with two variables but used with three in the second rule:

NetworkReported(n, s) :- RegionReported(
    r, s
) & RegionInNetwork(r, n)
StudyMatchingNetworkQuery(s, n) :- (
    RegionReported("VWFA", s)
    & NetworkReported(n, s, r)
)

add_note()#: Exception.add_note(note) – add a note to the exception

with_traceback()#: Exception.with_traceback(tb) – set self.__traceback__ to tb and return self.