org.ojalgo.function.multiary

Class ConstantFunction<N extends Number>

java.lang.Object

org.ojalgo.function.multiary.ConstantFunction<N>

All Implemented Interfaces:

BasicFunction, BasicFunction.PlainUnary<Access1D<N>,N>, MultiaryFunction<N>, MultiaryFunction.Constant<N,ConstantFunction<N>>, MultiaryFunction.TwiceDifferentiable<N>

public final class ConstantFunction<N extends Number>
extends Object

Constant valued function - always returns the same value.

Author:

apete

Nested Class Summary

Nested classes/interfaces inherited from interface org.ojalgo.function.multiary.MultiaryFunction

MultiaryFunction.Constant<N extends Number,F extends MultiaryFunction.Constant<N,?>>, MultiaryFunction.Convex<N extends Number>, MultiaryFunction.Linear<N extends Number>, MultiaryFunction.Quadratic<N extends Number>, MultiaryFunction.TwiceDifferentiable<N extends Number>

Nested classes/interfaces inherited from interface org.ojalgo.function.BasicFunction

BasicFunction.Differentiable<N extends Number,F extends BasicFunction>, BasicFunction.Integratable<N extends Number,F extends BasicFunction>, BasicFunction.PlainUnary<T,R>

Method Summary

Modifier and Type	Method and Description
int	arity()
F	constant(Number constant)
protected PhysicalStore.Factory<N,?>	factory()
N	getConstant()
MatrixStore<N>	getGradient(Access1D<N> point) The gradient of a scalar field is a vector field that points in the direction of the greatest rate of increase of the scalar field, and whose magnitude is that rate of increase.
MatrixStore<N>	getHessian(Access1D<N> point) The Hessian matrix or Hessian is a square matrix of second-order partial derivatives of a function.
Access1D<N>	getLinearFactors()
protected Scalar<N>	getScalarConstant()
N	invoke(Access1D<N> arg)
static ConstantFunction<ComplexNumber>	makeComplex(int arity)
static ConstantFunction<ComplexNumber>	makeComplex(int arity, Number constant)
static ConstantFunction<Double>	makePrimitive(int arity)
static ConstantFunction<Double>	makePrimitive(int arity, Number constant)
static ConstantFunction<RationalNumber>	makeRational(int arity)
static ConstantFunction<RationalNumber>	makeRational(int arity, Number constant)
void	setConstant(Number constant)
FirstOrderApproximation<N>	toFirstOrderApproximation(Access1D<N> arg)
SecondOrderApproximation<N>	toSecondOrderApproximation(Access1D<N> arg)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.ojalgo.function.multiary.MultiaryFunction

andThen

Method Detail

makeComplex

public static ConstantFunction<ComplexNumber> makeComplex(int arity)

makeComplex

public static ConstantFunction<ComplexNumber> makeComplex(int arity,
                                                          Number constant)

makePrimitive

public static ConstantFunction<Double> makePrimitive(int arity)

makePrimitive

public static ConstantFunction<Double> makePrimitive(int arity,
                                                     Number constant)

makeRational

public static ConstantFunction<RationalNumber> makeRational(int arity)

makeRational

public static ConstantFunction<RationalNumber> makeRational(int arity,
                                                            Number constant)

arity

public int arity()

getGradient

public MatrixStore<N> getGradient(Access1D<N> point)

Description copied from interface: MultiaryFunction.TwiceDifferentiable

The gradient of a scalar field is a vector field that points in the direction of the greatest rate of increase of the scalar field, and whose magnitude is that rate of increase.

The Jacobian is a generalization of the gradient. Gradients are only defined on scalar-valued functions, but Jacobians are defined on vector- valued functions. When f is real-valued (i.e., f : Rn → R) the derivative Df(x) is a 1 × n matrix, i.e., it is a row vector. Its transpose is called the gradient of the function: ∇f(x) = Df(x)^T , which is a (column) vector, i.e., in Rn. Its components are the partial derivatives of f:

The first-order approximation of f at a point x ∈ int dom f can be expressed as (the affine function of z) f(z) = f(x) + ∇f(x)T (z − x).

getHessian

public MatrixStore<N> getHessian(Access1D<N> point)

Description copied from interface: MultiaryFunction.TwiceDifferentiable

The Hessian matrix or Hessian is a square matrix of second-order partial derivatives of a function. It describes the local curvature of a function of many variables. The Hessian is the Jacobian of the gradient.

The second-order approximation of f, at or near x, is the quadratic function of z defined by f(z) = f(x) + ∇f(x)T (z − x) + (1/2)(z − x)T ∇2f(x)(z − x)

invoke

public N invoke(Access1D<N> arg)

factory

protected PhysicalStore.Factory<N,?> factory()

constant

public final F constant(Number constant)

Specified by:

constant in interface MultiaryFunction.Constant<N extends Number,F extends org.ojalgo.function.multiary.AbstractMultiary<N,?>>

getConstant

public final N getConstant()

Specified by:

getConstant in interface MultiaryFunction.Constant<N extends Number,F extends org.ojalgo.function.multiary.AbstractMultiary<N,?>>

getLinearFactors

public Access1D<N> getLinearFactors()

Specified by:

getLinearFactors in interface MultiaryFunction.TwiceDifferentiable<N extends Number>

Returns:

The gradient at 0 (0-vector)

setConstant

public final void setConstant(Number constant)

Specified by:

setConstant in interface MultiaryFunction.Constant<N extends Number,F extends org.ojalgo.function.multiary.AbstractMultiary<N,?>>

toFirstOrderApproximation

public final FirstOrderApproximation<N> toFirstOrderApproximation(Access1D<N> arg)

Specified by:

toFirstOrderApproximation in interface MultiaryFunction.TwiceDifferentiable<N extends Number>

toSecondOrderApproximation

public final SecondOrderApproximation<N> toSecondOrderApproximation(Access1D<N> arg)

Specified by:

toSecondOrderApproximation in interface MultiaryFunction.TwiceDifferentiable<N extends Number>

getScalarConstant

protected final Scalar<N> getScalarConstant()