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 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
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package org.apache.commons.math3.fitting;

import java.util.List;
import java.util.ArrayList;
import java.io.Serializable;

Simple container for weighted observed points used in curve fitting algorithms. 
Since:
3.3/**
 * Simple container for weighted observed points used
 * in {@link AbstractCurveFitter curve fitting} algorithms.
 *
 * @since 3.3
 */
public class WeightedObservedPoints implements Serializable {
    
Serializable version id. /** Serializable version id. */
    private static final long serialVersionUID = 20130813L;

    
Observed points. /** Observed points. */
    private final List<WeightedObservedPoint> observations
        = new ArrayList<WeightedObservedPoint>();

    
Adds a point to the sample. Calling this method is equivalent to calling add(1.0, x, y). 
Params:
x – Abscissa of the point.
y – Observed value at x. After fitting we should have f(x) as close as possible to this value.
See Also:
add(double, double, double)
add(WeightedObservedPoint)
toList()/**
     * Adds a point to the sample.
     * Calling this method is equivalent to calling
     * {@code add(1.0, x, y)}.
     *
     * @param x Abscissa of the point.
     * @param y Observed value  at {@code x}. After fitting we should
     * have {@code f(x)} as close as possible to this value.
     *
     * @see #add(double, double, double)
     * @see #add(WeightedObservedPoint)
     * @see #toList()
     */
    public void add(double x, double y) {
        add(1d, x, y);
    }

    
Adds a point to the sample.
Params:
weight – Weight of the observed point.
x – Abscissa of the point.
y – Observed value at x. After fitting we should have f(x) as close as possible to this value.
See Also:
add(double, double)
add(WeightedObservedPoint)
toList()/**
     * Adds a point to the sample.
     *
     * @param weight Weight of the observed point.
     * @param x Abscissa of the point.
     * @param y Observed value  at {@code x}. After fitting we should
     * have {@code f(x)} as close as possible to this value.
     *
     * @see #add(double, double)
     * @see #add(WeightedObservedPoint)
     * @see #toList()
     */
    public void add(double weight, double x, double y) {
        observations.add(new WeightedObservedPoint(weight, x, y));
    }

    
Adds a point to the sample.
Params:
observed – Observed point to add.
See Also:
add(double, double)
add(double, double, double)
toList()/**
     * Adds a point to the sample.
     *
     * @param observed Observed point to add.
     *
     * @see #add(double, double)
     * @see #add(double, double, double)
     * @see #toList()
     */
    public void add(WeightedObservedPoint observed) {
        observations.add(observed);
    }

    
Gets a snapshot of the observed points. The list of stored points is copied in order to ensure that modification of the returned instance does not affect this container. Conversely, further modification of this container (through the add or clear methods) will not affect the returned list. 
See Also:
add(double, double)
add(double, double, double)
add(WeightedObservedPoint)
Returns:
the observed points, in the order they were added to this
container./**
     * Gets a <em>snapshot</em> of the observed points.
     * The list of stored points is copied in order to ensure that
     * modification of the returned instance does not affect this
     * container.
     * Conversely, further modification of this container (through
     * the {@code add} or {@code clear} methods) will not affect the
     * returned list.
     *
     * @return the observed points, in the order they were added to this
     * container.
     *
     * @see #add(double, double)
     * @see #add(double, double, double)
     * @see #add(WeightedObservedPoint)
     */
    public List<WeightedObservedPoint> toList() {
        // The copy is necessary to ensure thread-safety because of the
        // "clear" method (which otherwise would be able to empty the
        // list of points while it is being used by another thread).
        return new ArrayList<WeightedObservedPoint>(observations);
    }

    
Removes all observations from this container.
/**
     * Removes all observations from this container.
     */
    public void clear() {
        observations.clear();
    }
}