package org.spaceroots.mantissa.functions.scalar;

import java.io.Serializable;

import org.spaceroots.mantissa.functions.FunctionException;

/** This interface represent sampled scalar functions.

 * 
A function sample is an ordered set of points of the form (x, y)
 * where x is the abscissa of the point and y is the function value at
 * x. It is typically a function that has been computed by external
 * means or the result of measurements.

 * 
The {@link ComputableFunctionSampler} class can be used to
 * transform classes implementing the {@link ComputableFunction}
 * interface into classes implementing this interface.

 * 
Sampled functions cannot be directly handled by integrators
 * implementing the {@link
 * org.spaceroots.mantissa.quadrature.scalar.SampledFunctionIntegrator
 * SampledFunctionIntegrator}. These integrators need a {@link
 * SampledFunctionIterator} object to iterate over the
 * sample.

 * @see SampledFunctionIterator
 * @see ComputableFunctionSampler
 * @see ComputableFunction

 * @version $Id: SampledFunction.java 1709 2006-12-03 21:16:50Z luc $
 * @author L. Maisonobe

 */
public interface SampledFunction extends Serializable {

  /** Get the number of points in the sample.
   * @return number of points in the sample
   */
  public int size();

  /** Get the abscissa and value of the sample at the specified index.
   * @param index index in the sample, should be between 0 and
   * {@link #size} - 1
   * @return abscissa and value of the sample at the specified index
   * @exception ArrayIndexOutOfBoundsException if the index is wrong
   * @exception FunctionException if an eventual underlying function
   * throws one
   */
  public ScalarValuedPair samplePointAt(int index)
    throws ArrayIndexOutOfBoundsException, FunctionException;

}