edu.stanford.nlp.optimization.DiffFunction Maven / Gradle / Ivy
package edu.stanford.nlp.optimization;
/**
* An interface for once-differentiable double-valued functions over
* double arrays. NOTE: it'd be good to have an AbstractDiffFunction
* that wrapped a Function with a finite-difference approximation.
*
* @author Dan Klein
* @version 1.0
* @see Function
* @since 1.0
*/
public interface DiffFunction extends Function {
/**
* Returns the first-derivative vector at the input location.
*
* @param x a double[] input vector
* @return the vector of first partial derivatives.
*/
double[] derivativeAt(double[] x);
}