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 Summary

Modifier and Type	Method and Description
default DoubleFunction1D	add(double a) For a DoubleFunction1D $g(x)$, adding a constant $a$ returns the function $h(x) = g(x) + a$.
default DoubleFunction1D	add(DoubleFunction1D f) For a DoubleFunction1D $g(x)$, adding a function $f(x)$ returns the function $h(x) = f(x) + g(x)$.
default DoubleFunction1D	derivative() Returns a function that calculates the first derivative.
default DoubleFunction1D	derivative(FiniteDifferenceType differenceType, double eps) Returns a function that calculates the first derivative.
default DoubleFunction1D	divide(double a) For a DoubleFunction1D $g(x)$, dividing by a constant $a$ returns the function $h(x) = \frac{g(x)}{a}$.
default DoubleFunction1D	divide(DoubleFunction1D f) For a DoubleFunction1D $g(x)$, dividing by a function $f(x)$ returns the function $h(x) = \frac{g(x)}{f(x)}$.
static DoubleFunction1D	from(Function<Double,Double> f) Converts a Function<Double, Double> into a DoubleFunction1D.
default DoubleFunction1D	multiply(double a) For a DoubleFunction1D $g(x)$, multiplying by a constant $a$ returns the function $h(x) = a g(x)$.
default DoubleFunction1D	multiply(DoubleFunction1D f) For a DoubleFunction1D $g(x)$, multiplying by a function $f(x)$ returns the function $h(x) = f(x) g(x)$.
default DoubleFunction1D	subtract(double a) For a DoubleFunction1D $g(x)$, subtracting a constant $a$ returns the function $h(x) = g(x) - a$.
default DoubleFunction1D	subtract(DoubleFunction1D f) For a DoubleFunction1D $g(x)$, subtracting a function $f(x)$ returns the function $h(x) = f(x) - g(x)$.

Methods inherited from interface java.util.function.DoubleUnaryOperator

andThen, applyAsDouble, compose, identity

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