# LSExternalContext Class¶

class

Context of an external function.

External contexts can be used to query and set properties of the associated external function.

If you known the bounds of the external 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::getExternalContext() 9.5

## Summary¶

 getIntLowerBound Gets the lower bound of the external function. getIntUpperBound Gets the upper bound of the external function. getDoubleLowerBound Gets the lower bound of the external function. getDoubleUpperBound Gets the upper bound of the external function. isNanable Returns true if the function can return a NaN (Not a Number) value. setLowerBound Sets the lower bound of the external function. setUpperBound Sets the upper bound of the external function. setIntLowerBound Sets the lower bound of the external function. setIntUpperBound Sets the upper bound of the external function. setDoubleLowerBound Sets the lower bound of the external function. setDoubleUpperBound Sets the upper bound of the external function. setNanable Sets whether or not the function can return a NaN (Not a Number) value.

## Functions¶

lsint localsolver::LSExternalContext::getIntLowerBound()
const

Gets the lower bound of the external function.

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

Return: Lower bound of the external function.

lsint localsolver::LSExternalContext::getIntUpperBound()
const

Gets the upper bound of the external function.

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

Return: Upper bound of the external function.

lsdouble localsolver::LSExternalContext::getDoubleLowerBound()
const

Gets the lower bound of the external function.

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

Return: Lower bound of the external function.

lsdouble localsolver::LSExternalContext::getDoubleUpperBound()
const

Gets the upper bound of the external function.

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

Return: Upper bound of the external function.

bool localsolver::LSExternalContext::isNanable()
const

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

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

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

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

Sets the lower bound of the external function.

Only allowed if the external function is an integer function. Only allowed in state S_Modeling. This method has the same behaviour as LSExternalContext#setIntLowerBound(lsint)

Parameters: lowerBound - Lower bound of the function.

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

Sets the lower bound of the external function.

Only allowed if the external function is a double function. Only allowed in state S_Modeling. This method has the same behaviour as LSExternalContext#setDoubleLowerBound(lsdouble)

Parameters: lowerBound - Lower bound of the function

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

Sets the upper bound of the external function.

Only allowed if the external function is an integer function. Only allowed in state S_Modeling. This method has the same behaviour as LSExternalContext#setIntUpperBound(lsint)

Parameters: upperBound - Upper bound of the function.

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

Sets the upper bound of the external function.

Only allowed if the external function is a double function. Only allowed in state S_Modeling. This method has the same behaviour as LSExternalContext#setDoubleLowerBound(lsdouble)

Parameters: upperBound - Upper bound of the function.

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

Sets the lower bound of the external function.

Only allowed if the external function is an integer function.

Parameters: lowerBound - Lower bound of the function

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

Sets the upper bound of the external function.

Only allowed if the external function is an integer function. Only allowed in state S_Modeling.

Parameters: upperBound - Upper bound of the function.

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

Sets the lower bound of the external function.

Only allowed if the external function is a double function.

Parameters: lowerBound - Lower bound of the function.

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

Sets the upper bound of the external function.

Only allowed if the external function is a double function. Only allowed in state S_Modeling.

Parameters: upperBound - Upper bound of the function.

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

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

Only allowed if the external function is a double function. Only allowed in state S_Modeling.

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