# LSBlackBoxFunction Interface¶

template <typename T>
class

Black-box function interface.

To use your own black-box functions within LocalSolver, you have to first define your black-box function in one of two ways:

• Implement the LSBlackBoxFunction interface with the call method. The call method must take a LSBlackBoxArgumentValues as single argument and must return a lsdouble or a lsint value. The argument values contain the values of the expressions passed to the function. A distinction is made between integer arguments (bool, int) and floating point arguments (double)
• If your program is compiled with C++11, you can use a function, a functor or a lambda function instead. This function may take any number of lsint and lsdouble arguments, or alternatively a single LSBlackBoxArgumentValues. It must return a lsdouble or a lsint value.

Then:

1. Instantiate the function as an LSExpression with LSModel#createBlackBoxFunction or the dedicated shortcut LSModel#blackBoxFunction.
2. Pass arguments to your function and call it using LSModel#call. The first operand must the LSExpression returned by createBlackBoxFunction. The other operands must be LSExpressions, whose values will be made accessible to your black-box function when it is called.

Note 1: LocalSolver does not manage memory of objects created outside of its environment. You are responsible for the lifetime of your LSBlackBoxFunction, which must last as long as the search is active.

Node 2: You can provide additional data for your function (such as bounds or the maximum number of evaluations) with the help of the LSBlackBoxContext associated with your function (see LSExpression#getBlackBoxContext()).

 Since: 9.5

## Summary¶

 call The function to call.

## Functions¶

virtual template<>
T localsolver::LSBlackBoxFunction<T>::call(const LSBlackBoxArgumentValues &argumentValues)
= 0

The function to call.

The argument values contain the arguments to pass to your function.

Return: The value of the LSExpression. argumentValues - Values of the arguments passed to the function.