# LSBlackBoxContext Class¶

class

Context of a black-box function.

Black-box contexts can be used to query and set properties of the associated black-box function.

If you known the bounds of the black-box function or if you know it cannot return a NaN value, we recommend you to specify it as LocalSolver is then able to improve its search process. But beware! If the evaluation of the function returns an unexpected value (like a value outside of the bounds), an exception will be thrown during the search.

See: LSExpression::getBlackBoxContext() 9.5

## Summary¶

 getIntLowerBound Gets the lower bound of the black-box function. getIntUpperBound Gets the upper bound of the black-box function. getDoubleLowerBound Gets the lower bound of the black-box function. getDoubleUpperBound Gets the upper bound of the black-box function. isNanable Returns true if the function can return a NaN (Not a Number) value. getEvaluationLimit Returns the maximum number of black-box evaluations. setLowerBound Sets the lower bound of the black-box function. setUpperBound Sets the upper bound of the black-box function. setIntLowerBound Sets the lower bound of the black-box function. setIntUpperBound Sets the upper bound of the black-box function. setDoubleLowerBound Sets the lower bound of the black-box function. setDoubleUpperBound Sets the upper bound of the black-box function. setNanable Sets whether or not the function can return a NaN (Not a Number) value. setEvaluationLimit Sets the maximum number of black-box evaluations. createEvaluationPoint Creates an evaluation point for the black-box function. getNbEvaluationPoints Returns the number of black-box evaluation points. getEvaluationPoint Returns the black-box evaluation point at the given position.

## Functions¶

lsint localsolver::LSBlackBoxContext::getIntLowerBound()
const

Gets the lower bound of the black-box function.

Only allowed if the black-box function is an integer function. By default, this property is set to LONG_LONG_MIN.

Return: Lower bound of the black-box function.

lsint localsolver::LSBlackBoxContext::getIntUpperBound()
const

Gets the upper bound of the black-box function.

Only allowed if the black-box function is an integer function. By default, this property is set to LONG_LONG_MAX.

Return: Upper bound of the black-box function.

lsdouble localsolver::LSBlackBoxContext::getDoubleLowerBound()
const

Gets the lower bound of the black-box function.

Only allowed if the black-box function is a double function. By default, this property is set to -INFINITY.

Return: Lower bound of the black-box function.

lsdouble localsolver::LSBlackBoxContext::getDoubleUpperBound()
const

Gets the upper bound of the black-box function.

Only allowed if the black-box function is a double function. By default, this property is set to INFINITY.

Return: Upper bound of the black-box function.

bool localsolver::LSBlackBoxContext::isNanable()
const

Returns true if the function can return a NaN (Not a Number) value.

Only allowed if the black-box function is a double function. By default this property is set to true.

Return: True if the function can return a NaN value.

int localsolver::LSBlackBoxContext::getEvaluationLimit()
const

Returns the maximum number of black-box evaluations.

By default, the maximum number of evaluations is set to the largest positive integer on 32 bits, that is 2^31-1 = 2,147,483,647 > 10^9.

Return: Maximum number of calls to the black-box function.

void localsolver::LSBlackBoxContext::setLowerBound(lsint lowerBound)

Sets the lower bound of the black-box function.

Only allowed if the black-box function is an integer function. Only allowed in state S_Modeling. This method has the same behaviour as LSBlackBoxContext#setIntLowerBound(lsint)

Parameters: lowerBound - Lower bound of the function.

void localsolver::LSBlackBoxContext::setLowerBound(lsdouble lowerBound)

Sets the lower bound of the black-box function.

Only allowed if the black-box function is a double function. Only allowed in state S_Modeling. This method has the same behaviour as LSBlackBoxContext#setDoubleLowerBound(lsdouble)

Parameters: lowerBound - Lower bound of the function

void localsolver::LSBlackBoxContext::setUpperBound(lsint upperBound)

Sets the upper bound of the black-box function.

Only allowed if the black-box function is an integer function. Only allowed in state S_Modeling. This method has the same behaviour as LSBlackBoxContext#setIntUpperBound(lsint)

Parameters: upperBound - Upper bound of the function.

void localsolver::LSBlackBoxContext::setUpperBound(lsdouble upperBound)

Sets the upper bound of the black-box function.

Only allowed if the black-box function is a double function. Only allowed in state S_Modeling. This method has the same behaviour as LSBlackBoxContext#setDoubleLowerBound(lsdouble)

Parameters: upperBound - Upper bound of the function.

void localsolver::LSBlackBoxContext::setIntLowerBound(lsint lowerBound)

Sets the lower bound of the black-box function.

Only allowed if the black-box function is an integer function.

Parameters: lowerBound - Lower bound of the function

void localsolver::LSBlackBoxContext::setIntUpperBound(lsint upperBound)

Sets the upper bound of the black-box function.

Only allowed if the black-box function is an integer function. Only allowed in state S_Modeling.

Parameters: upperBound - Upper bound of the function.

void localsolver::LSBlackBoxContext::setDoubleLowerBound(lsdouble lowerBound)

Sets the lower bound of the black-box function.

Only allowed if the black-box function is a double function.

Parameters: lowerBound - Lower bound of the function.

void localsolver::LSBlackBoxContext::setDoubleUpperBound(lsdouble upperBound)

Sets the upper bound of the black-box function.

Only allowed if the black-box function is a double function. Only allowed in state S_Modeling.

Parameters: upperBound - Upper bound of the function.

void localsolver::LSBlackBoxContext::setNanable(bool nanable)

Sets whether or not the function can return a NaN (Not a Number) value.

Only allowed if the black-box function is a double function. Only allowed in state S_Modeling.

Parameters: nanable - True if the function can return a NaN value, false otherwise.

void localsolver::LSBlackBoxContext::setEvaluationLimit(int evaluationLimit)

Sets the maximum number of black-box evaluations.

By default, the maximum number of evaluations is set to the largest positive integer on 32 bits, that is 2^31-1 = 2,147,483,647 > 10^9. Only allowed in state S_Stopped.

Parameters: evaluationLimit - Maximum number of calls to the black-box function.

LSBlackBoxEvaluationPoint localsolver::LSBlackBoxContext::createEvaluationPoint()

Creates an evaluation point for the black-box function.

It consists of a list of values corresponding to the function’s arguments and return value.

Evaluation points are used to specify known points for a function in advance. It can be useful to warm-start the solver when the function is particularly expensive to evaluate, or if you already have a good estimate of the optimal point.

Only allowed in state S_Stopped.

Return: Black-box evaluation point. LSBlackBoxEvaluationPoint

int localsolver::LSBlackBoxContext::getNbEvaluationPoints()
const

Returns the number of black-box evaluation points.

Only allowed in state S_Stopped.

Return: Number of black-box evaluation points.

LSBlackBoxEvaluationPoint localsolver::LSBlackBoxContext::getEvaluationPoint(int pos)

Returns the black-box evaluation point at the given position.

Only allowed in state S_Stopped.

Return: Black-box evaluation point at the given position. LSBlackBoxEvaluationPoint pos - Position of the black-box evaluation point.