Package com.opengamma.strata.math.impl.function

Interface DoubleFunction1D

  • All Superinterfaces:
    DoubleUnaryOperator
    All Known Implementing Classes:
    RealPolynomialFunction1D
    public interface DoubleFunction1D
extends DoubleUnaryOperator
    Defines a family of functions that take real arguments and return real values. The functionality of Function is extended; this class allows arithmetic operations on functions and defines a derivative function.

    • Method Detail

      • derivative

        default DoubleFunction1D derivative()
        Returns a function that calculates the first derivative.

        The method used is central finite difference, with $\epsilon = 10^{-5}$. Implementing classes can override this method to return a function that is the exact functional representation of the first derivative.

        Returns:
        a function that calculates the first derivative of this function

      • derivative

        default DoubleFunction1D derivative​(FiniteDifferenceType differenceType,
                                    double eps)
        Returns a function that calculates the first derivative. The method used is finite difference, with the differencing type and $\epsilon$ as arguments.
        Parameters:
        differenceType - the differencing type to use
        eps - the $\epsilon$ to use
        Returns:
        a function that calculates the first derivative of this function

      • add

        default DoubleFunction1D add​(DoubleFunction1D f)
        For a DoubleFunction1D $g(x)$, adding a function $f(x)$ returns the function $h(x) = f(x) + g(x)$.
        Parameters:
        f - the function to add
        Returns:
        a function $h(x) = f(x) + g(x)$

      • add

        default DoubleFunction1D add​(double a)
        For a DoubleFunction1D $g(x)$, adding a constant $a$ returns the function $h(x) = g(x) + a$.
        Parameters:
        a - the constant to add
        Returns:
        a function $h(x) = g(x) + a$

      • divide

        default DoubleFunction1D divide​(DoubleFunction1D f)
        For a DoubleFunction1D $g(x)$, dividing by a function $f(x)$ returns the function $h(x) = \frac{g(x)}{f(x)}$.
        Parameters:
        f - the function to divide by
        Returns:
        a function $h(x) = \frac{f(x)}{g(x)}$

      • divide

        default DoubleFunction1D divide​(double a)
        For a DoubleFunction1D $g(x)$, dividing by a constant $a$ returns the function $h(x) = \frac{g(x)}{a}$.
        Parameters:
        a - the constant to add
        Returns:
        a function $h(x) = \frac{g(x)}{a}$

      • multiply

        default DoubleFunction1D multiply​(DoubleFunction1D f)
        For a DoubleFunction1D $g(x)$, multiplying by a function $f(x)$ returns the function $h(x) = f(x) g(x)$.
        Parameters:
        f - the function to multiply by
        Returns:
        a function $h(x) = f(x) g(x)$

      • multiply

        default DoubleFunction1D multiply​(double a)
        For a DoubleFunction1D $g(x)$, multiplying by a constant $a$ returns the function $h(x) = a g(x)$.
        Parameters:
        a - the constant to add
        Returns:
        a function $h(x) = a g(x)$

      • subtract

        default DoubleFunction1D subtract​(DoubleFunction1D f)
        For a DoubleFunction1D $g(x)$, subtracting a function $f(x)$ returns the function $h(x) = f(x) - g(x)$.
        Parameters:
        f - the function to subtract
        Returns:
        a function $h(x) = g(x) - f(x)$

      • subtract

        default DoubleFunction1D subtract​(double a)
        For a DoubleFunction1D $g(x)$, subtracting a constant $a$ returns the function $h(x) = g(x) - a$.
        Parameters:
        a - the constant to add
        Returns:
        a function $h(x) = g(x) - a$

      • from

        static DoubleFunction1D from​(Function<Double,​Double> f)
        Converts a Function<Double, Double> into a DoubleFunction1D.
        Parameters:
        f - the function to convert
        Returns:
        the converted function