Nonlinear operator¶
The class NonLinearOperator consists of a collection of a function and its derivatives, including their dependence
on parameters.
Let us assume a function f(x) and its derivative df(x).
Then, a NonLinearOperator can be constructed as follows:
double x = 13;
auto fvLambda = [&](auto&& x) { return f(x); };
auto dfvLambda = [&](auto&& x) { return df(x); };
auto nonLinOp = Ikarus::NonLinearOperator(linearAlgebraFunctions(fvLambda, dfvLambda), parameter(x));
Note
It is assumed that the second function is the derivative of the first function, the third function is the derivative of the second function (2nd derivative of the first function), and so on.
linearAlgebraFunctions(...) and parameter(...) are helper functions. They are necessary to distinguish which argument is a function and which argument is a parameter.
nonLinOp provides the following features:
void updateAll()
void update<n>()
auto& value()
auto& derivative()
auto& secondDerivative()
auto& nthDerivative<n>()
auto& firstParameter()
auto& secondParameter()
auto& nthParameter<n>()
auto& lastParameter()
auto subOperator<n,m,...>()