PROMedSRobustRangingAndRssiRadioSourceEstimator2D.java

/*
 * Copyright (C) 2018 Alberto Irurueta Carro (alberto@irurueta.com)
 *
 * Licensed 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
 * limitations under the License.
 */
package com.irurueta.navigation.indoor.radiosource;

import com.irurueta.geometry.Point2D;
import com.irurueta.navigation.LockedException;
import com.irurueta.navigation.NotReadyException;
import com.irurueta.navigation.indoor.RadioSource;
import com.irurueta.navigation.indoor.RangingAndRssiReadingLocated;
import com.irurueta.numerical.robust.PROMedSRobustEstimator;
import com.irurueta.numerical.robust.PROMedSRobustEstimatorListener;
import com.irurueta.numerical.robust.RobustEstimator;
import com.irurueta.numerical.robust.RobustEstimatorException;
import com.irurueta.numerical.robust.RobustEstimatorMethod;

import java.util.List;

/**
 * Robustly estimate 2D position, transmitted power and path-loss
 * exponent of a radio source (e.g. Wi-Fi access point or bluetooth beacon), by discarding
 * outliers using PROMedS algorithm and assuming that the ranging data is available to
 * obtain position with greater accuracy and that the radio source emits isotropically
 * following the expression below:
 * Pr = Pt*Gt*Gr*lambda^2 / (4*pi*d)^2,
 * where Pr is the received power (expressed in mW),
 * Gt is the Gain of the transmission antenna
 * Gr is the Gain of the receiver antenna
 * d is the distance between emitter and receiver
 * and lambda is the wavelength and is equal to: lambda = c / f,
 * where c is the speed of light
 * and f is the carrier frequency of the radio signal.
 * Because usually information about the antenna of the radio source cannot be
 * retrieved (because many measurements are made on unknown devices where
 * physical access is not possible), this implementation will estimate the
 * equivalent transmitted power as: Pte = Pt * Gt * Gr.
 * If Readings contain RSSI standard deviations, those values will be used,
 * otherwise it will be assumed an RSSI standard deviation of 1 dB.
 *
 * @param <S> a {@link RadioSource} type.
 */
@SuppressWarnings("Duplicates")
public class PROMedSRobustRangingAndRssiRadioSourceEstimator2D<S extends RadioSource> extends
        RobustRangingAndRssiRadioSourceEstimator2D<S> {

    /**
     * Default value to be used for stop threshold. Stop threshold can be used to
     * avoid keeping the algorithm unnecessarily iterating in case that best
     * estimated threshold using median of residuals is not small enough. Once a
     * solution is found that generates a threshold below this value, the
     * algorithm will stop.
     * The stop threshold can be used to prevent the LMedS algorithm iterating
     * too many times in cases where samples have a very similar accuracy.
     * For instance, in cases where proportion of outliers is very small (close
     * to 0%), and samples are very accurate (i.e. 1e-6), the algorithm would
     * iterate for a long time trying to find the best solution when indeed
     * there is no need to do that if a reasonable threshold has already been
     * reached.
     * Because of this behaviour the stop threshold can be set to a value much
     * lower than the one typically used in RANSAC, and yet the algorithm could
     * still produce even smaller thresholds in estimated results.
     */
    public static final double DEFAULT_STOP_THRESHOLD = 1e-4;

    /**
     * Minimum allowed stop threshold value.
     */
    public static final double MIN_STOP_THRESHOLD = 0.0;

    /**
     * Threshold to be used to keep the algorithm iterating in case that best
     * estimated threshold using median of residuals is not small enough. Once
     * a solution is found that generates a threshold below this value, the
     * algorithm will stop.
     * The stop threshold can be used to prevent the LMedS algorithm iterating
     * too many times in cases where samples have a very similar accuracy.
     * For instance, in cases where proportion of outliers is very small (close
     * to 0%), and samples are very accurate (i.e. 1e-6), the algorithm would
     * iterate for a long time trying to find the best solution when indeed
     * there is no need to do that if a reasonable threshold has already been
     * reached.
     * Because of this behaviour the stop threshold can be set to a value much
     * lower than the one typically used in RANSAC, and yet the algorithm could
     * still produce even smaller thresholds in estimated results.
     */
    private double stopThreshold = DEFAULT_STOP_THRESHOLD;

    /**
     * Quality scores corresponding to each provided sample.
     * The larger the score value the better the quality of the sample.
     */
    private double[] qualityScores;

    /**
     * Constructor.
     */
    public PROMedSRobustRangingAndRssiRadioSourceEstimator2D() {
        super();
    }

    /**
     * Constructor.
     * Sets signal readings belonging to the same radio source.
     *
     * @param readings signal readings belonging to the same radio source.
     * @throws IllegalArgumentException if readings are not valid.
     */
    public PROMedSRobustRangingAndRssiRadioSourceEstimator2D(
            final List<? extends RangingAndRssiReadingLocated<S, Point2D>> readings) {
        super(readings);
    }

    /**
     * Constructor.
     *
     * @param listener listener in charge of attending events raised by this instance.
     */
    public PROMedSRobustRangingAndRssiRadioSourceEstimator2D(
            final RobustRangingAndRssiRadioSourceEstimatorListener<S, Point2D> listener) {
        this.listener = listener;
    }

    /**
     * Constructor.
     * Sets signal readings belonging to the same radio source.
     *
     * @param readings signal readings belonging to the same radio source.
     * @param listener listener in charge of attending events raised by this instance.
     * @throws IllegalArgumentException if readings are not valid.
     */
    public PROMedSRobustRangingAndRssiRadioSourceEstimator2D(
            final List<? extends RangingAndRssiReadingLocated<S, Point2D>> readings,
            final RobustRangingAndRssiRadioSourceEstimatorListener<S, Point2D> listener) {
        super(readings, listener);
    }

    /**
     * Constructor.
     * Sets signal readings belonging to the same radio source.
     *
     * @param readings        signal readings belonging to the same radio source.
     * @param initialPosition initial position to start the estimation of access
     *                        point position.
     * @throws IllegalArgumentException if readings are not valid.
     */
    public PROMedSRobustRangingAndRssiRadioSourceEstimator2D(
            final List<? extends RangingAndRssiReadingLocated<S, Point2D>> readings, final Point2D initialPosition) {
        super(readings, initialPosition);
    }

    /**
     * Constructor.
     *
     * @param initialPosition initial position to start the estimation of access
     *                        point position.
     */
    public PROMedSRobustRangingAndRssiRadioSourceEstimator2D(final Point2D initialPosition) {
        super(initialPosition);
    }

    /**
     * Constructor.
     *
     * @param initialPosition initial position to start the estimation of access
     *                        point position.
     * @param listener        listener in charge of attending events raised by this instance.
     */
    public PROMedSRobustRangingAndRssiRadioSourceEstimator2D(
            final Point2D initialPosition,
            final RobustRangingAndRssiRadioSourceEstimatorListener<S, Point2D> listener) {
        super(initialPosition, listener);
    }

    /**
     * Constructor.
     * Sets signal readings belonging to the same radio source.
     *
     * @param readings        signal readings belonging to the same radio source.
     * @param initialPosition initial position to start the estimation of radio
     *                        source position.
     * @param listener        listener in charge of attending events raised by this instance.
     * @throws IllegalArgumentException if readings are not valid.
     */
    public PROMedSRobustRangingAndRssiRadioSourceEstimator2D(
            final List<? extends RangingAndRssiReadingLocated<S, Point2D>> readings, final Point2D initialPosition,
            final RobustRangingAndRssiRadioSourceEstimatorListener<S, Point2D> listener) {
        super(readings, initialPosition, listener);
    }

    /**
     * Constructor.
     *
     * @param initialTransmittedPowerdBm initial transmitted power to start the
     *                                   estimation of radio source transmitted power
     *                                   (expressed in dBm's)
     */
    public PROMedSRobustRangingAndRssiRadioSourceEstimator2D(final Double initialTransmittedPowerdBm) {
        super(initialTransmittedPowerdBm);
    }

    /**
     * Constructor.
     * Sets signal readings belonging to the same radio source.
     *
     * @param readings                   signal readings belonging to the same radio source.
     * @param initialTransmittedPowerdBm initial transmitted power to start the
     *                                   estimation of radio source transmitted power
     *                                   (expressed in dBm's)
     * @throws IllegalArgumentException if readings are not valid.
     */
    public PROMedSRobustRangingAndRssiRadioSourceEstimator2D(
            final List<? extends RangingAndRssiReadingLocated<S, Point2D>> readings,
            final Double initialTransmittedPowerdBm) {
        super(readings, initialTransmittedPowerdBm);
    }

    /**
     * Constructor.
     *
     * @param initialTransmittedPowerdBm initial transmitted power to start the
     *                                   estimation of radio source transmitted power
     *                                   (expressed in dBm's)
     * @param listener                   listener in charge of attending events raised by this instance.
     */
    public PROMedSRobustRangingAndRssiRadioSourceEstimator2D(
            final Double initialTransmittedPowerdBm,
            final RobustRangingAndRssiRadioSourceEstimatorListener<S, Point2D> listener) {
        super(initialTransmittedPowerdBm, listener);
    }

    /**
     * Constructor.
     * Sets signal readings belonging to the same radio source.
     *
     * @param readings                   signal readings belonging to the same radio source.
     * @param initialTransmittedPowerdBm initial transmitted power to start the
     *                                   estimation of radio source transmitted power
     *                                   (expressed in dBm's)
     * @param listener                   listener in charge of attending events raised by this instance.
     * @throws IllegalArgumentException if readings are not valid.
     */
    public PROMedSRobustRangingAndRssiRadioSourceEstimator2D(
            final List<? extends RangingAndRssiReadingLocated<S, Point2D>> readings,
            final Double initialTransmittedPowerdBm,
            final RobustRangingAndRssiRadioSourceEstimatorListener<S, Point2D> listener) {
        super(readings, initialTransmittedPowerdBm, listener);
    }

    /**
     * Constructor.
     * Sets signal readings belonging to the same radio source.
     *
     * @param readings                   signal readings belonging to the same radio source.
     * @param initialPosition            initial position to start the estimation of access
     *                                   point position.
     * @param initialTransmittedPowerdBm initial transmitted power to start the
     *                                   estimation of radio source transmitted power
     *                                   (expressed in dBm's).
     * @throws IllegalArgumentException if readings are not valid.
     */
    public PROMedSRobustRangingAndRssiRadioSourceEstimator2D(
            final List<? extends RangingAndRssiReadingLocated<S, Point2D>> readings, final Point2D initialPosition,
            final Double initialTransmittedPowerdBm) {
        super(readings, initialPosition, initialTransmittedPowerdBm);
    }

    /**
     * Constructor.
     *
     * @param initialPosition            initial position to start the estimation of radio
     *                                   source position.
     * @param initialTransmittedPowerdBm initial transmitted power to start the
     *                                   estimation of radio source transmitted power
     *                                   (expressed in dBm's).
     */
    public PROMedSRobustRangingAndRssiRadioSourceEstimator2D(
            final Point2D initialPosition, final Double initialTransmittedPowerdBm) {
        super(initialPosition, initialTransmittedPowerdBm);
    }

    /**
     * Constructor.
     *
     * @param initialPosition            initial position to start the estimation of radio
     *                                   source position.
     * @param initialTransmittedPowerdBm initial transmitted power to start the
     *                                   estimation of radio source transmitted power
     *                                   (expressed in dBm's).
     * @param listener                   in charge of attending events raised by this instance.
     */
    public PROMedSRobustRangingAndRssiRadioSourceEstimator2D(
            final Point2D initialPosition, final Double initialTransmittedPowerdBm,
            final RobustRangingAndRssiRadioSourceEstimatorListener<S, Point2D> listener) {
        super(initialPosition, initialTransmittedPowerdBm, listener);
    }

    /**
     * Constructor.
     * Sets signal readings belonging to the same radio source.
     *
     * @param readings                   Wi-Fi signal readings belonging to the same radio source.
     * @param initialPosition            initial position to start the estimation of radio
     *                                   source position.
     * @param initialTransmittedPowerdBm initial transmitted power to start the
     *                                   estimation of radio source transmitted power
     *                                   (expressed in dBm's).
     * @param listener                   listener in charge of attending events raised by this instance.
     * @throws IllegalArgumentException if readings are not valid.
     */
    public PROMedSRobustRangingAndRssiRadioSourceEstimator2D(
            final List<? extends RangingAndRssiReadingLocated<S, Point2D>> readings, final Point2D initialPosition,
            final Double initialTransmittedPowerdBm,
            final RobustRangingAndRssiRadioSourceEstimatorListener<S, Point2D> listener) {
        super(readings, initialPosition, initialTransmittedPowerdBm, listener);
    }

    /**
     * Constructor.
     * Sets signal readings belonging to the same radio source.
     *
     * @param readings                   signal readings belonging to the same radio source.
     * @param initialPosition            initial position to start the estimation of radio
     *                                   source position.
     * @param initialTransmittedPowerdBm initial transmitted power to start the
     *                                   estimation of radio source transmitted power
     *                                   (expressed in dBm's).
     * @param initialPathLossExponent    initial path loss exponent. A typical value is 2.0.
     * @throws IllegalArgumentException if readings are not valid.
     */
    public PROMedSRobustRangingAndRssiRadioSourceEstimator2D(
            final List<? extends RangingAndRssiReadingLocated<S, Point2D>> readings, final Point2D initialPosition,
            final Double initialTransmittedPowerdBm, final double initialPathLossExponent) {
        super(readings, initialPosition, initialTransmittedPowerdBm, initialPathLossExponent);
    }

    /**
     * Constructor.
     *
     * @param initialPosition            initial position to start the estimation of radio
     *                                   source position.
     * @param initialTransmittedPowerdBm initial transmitted power to start the
     *                                   estimation of radio source transmitted power
     *                                   (expressed in dBm's).
     * @param initialPathLossExponent    initial path loss exponent. A typical value is 2.0.
     */
    public PROMedSRobustRangingAndRssiRadioSourceEstimator2D(
            final Point2D initialPosition, final Double initialTransmittedPowerdBm,
            final double initialPathLossExponent) {
        super(initialPosition, initialTransmittedPowerdBm, initialPathLossExponent);
    }

    /**
     * Constructor.
     *
     * @param initialPosition            initial position to start the estimation of radio
     *                                   source position.
     * @param initialTransmittedPowerdBm initial transmitted power to start the
     *                                   estimation of radio source transmitted power
     *                                   (expressed in dBm's).
     * @param initialPathLossExponent    initial path loss exponent. A typical value is 2.0.
     * @param listener                   listener in charge of attending events raised by this instance.
     */
    public PROMedSRobustRangingAndRssiRadioSourceEstimator2D(
            final Point2D initialPosition, final Double initialTransmittedPowerdBm,
            final double initialPathLossExponent,
            final RobustRangingAndRssiRadioSourceEstimatorListener<S, Point2D> listener) {
        super(initialPosition, initialTransmittedPowerdBm, initialPathLossExponent, listener);
    }

    /**
     * Constructor.
     * Sets signal readings belonging to the same radio source.
     *
     * @param readings                   signal readings belonging to the same radio source.
     * @param initialPosition            initial position to start the estimation of radio
     *                                   source position.
     * @param initialTransmittedPowerdBm initial transmitted power to start the
     *                                   estimation of radio source transmitted power
     *                                   (expressed in dBm's).
     * @param initialPathLossExponent    initial path loss exponent. A typical value is 2.0.
     * @param listener                   listener in charge of attending events raised by this instance.
     * @throws IllegalArgumentException if readings are not valid.
     */
    public PROMedSRobustRangingAndRssiRadioSourceEstimator2D(
            final List<? extends RangingAndRssiReadingLocated<S, Point2D>> readings, final Point2D initialPosition,
            final Double initialTransmittedPowerdBm, final double initialPathLossExponent,
            final RobustRangingAndRssiRadioSourceEstimatorListener<S, Point2D> listener) {
        super(readings, initialPosition, initialTransmittedPowerdBm, initialPathLossExponent, listener);
    }

    /**
     * Constructor.
     *
     * @param qualityScores quality scores corresponding to each provided
     *                      sample. The larger the score value the better
     *                      the quality of the sample.
     * @throws IllegalArgumentException if quality scores is null, or length
     *                                  of quality scores is less than required minimum.
     */
    public PROMedSRobustRangingAndRssiRadioSourceEstimator2D(final double[] qualityScores) {
        super();
        internalSetQualityScores(qualityScores);
    }

    /**
     * Constructor.
     * Sets signal readings belonging to the same radio source.
     *
     * @param qualityScores quality scores corresponding to each provided
     *                      sample. The larger the score value the better
     *                      the quality of the sample.
     * @param readings      signal readings belonging to the same radio source.
     * @throws IllegalArgumentException if readings are not valid, quality scores
     *                                  is null, or length of quality scores is less than required minimum.
     */
    public PROMedSRobustRangingAndRssiRadioSourceEstimator2D(
            final double[] qualityScores, final List<? extends RangingAndRssiReadingLocated<S, Point2D>> readings) {
        super(readings);
        internalSetQualityScores(qualityScores);
    }

    /**
     * Constructor.
     *
     * @param qualityScores quality scores corresponding to each provided
     *                      sample. The larger the score value the better
     *                      the quality of the sample.
     * @param listener      listener in charge of attending events raised by this instance.
     * @throws IllegalArgumentException if quality scores is null, or length
     *                                  of quality scores is less than required minimum.
     */
    public PROMedSRobustRangingAndRssiRadioSourceEstimator2D(
            final double[] qualityScores, final RobustRangingAndRssiRadioSourceEstimatorListener<S, Point2D> listener) {
        super(listener);
        internalSetQualityScores(qualityScores);
    }

    /**
     * Constructor.
     * Sets signal readings belonging to the same radio source.
     *
     * @param qualityScores quality scores corresponding to each provided
     *                      sample. The larger the score value the better
     *                      the quality of the sample.
     * @param readings      signal readings belonging to the same radio source.
     * @param listener      listener in charge of attending events raised by this instance.
     * @throws IllegalArgumentException if readings are not valid, quality scores
     *                                  is null, or length of quality scores is less than required minimum.
     */
    public PROMedSRobustRangingAndRssiRadioSourceEstimator2D(
            final double[] qualityScores, final List<? extends RangingAndRssiReadingLocated<S, Point2D>> readings,
            final RobustRangingAndRssiRadioSourceEstimatorListener<S, Point2D> listener) {
        super(readings, listener);
        internalSetQualityScores(qualityScores);
    }

    /**
     * Constructor.
     * Sets signal readings belonging to the same radio source.
     *
     * @param qualityScores   quality scores corresponding to each provided
     *                        sample. The larger the score value the better
     *                        the quality of the sample.
     * @param readings        signal readings belonging to the same radio source.
     * @param initialPosition initial position to start the estimation of radio
     *                        source position.
     * @throws IllegalArgumentException if readings are not valid, quality scores
     *                                  is null, or length of quality scores is less than required minimum.
     */
    public PROMedSRobustRangingAndRssiRadioSourceEstimator2D(
            final double[] qualityScores, final List<? extends RangingAndRssiReadingLocated<S, Point2D>> readings,
            final Point2D initialPosition) {
        super(readings, initialPosition);
        internalSetQualityScores(qualityScores);
    }

    /**
     * Constructor.
     *
     * @param qualityScores   quality scores corresponding to each provided
     *                        sample. The larger the score value the better
     *                        the quality of the sample.
     * @param initialPosition initial position to start the estimation of radio
     *                        source position.
     */
    public PROMedSRobustRangingAndRssiRadioSourceEstimator2D(
            final double[] qualityScores, final Point2D initialPosition) {
        super(initialPosition);
        internalSetQualityScores(qualityScores);
    }

    /**
     * Constructor.
     *
     * @param qualityScores   quality scores corresponding to each provided
     *                        sample. The larger the score value the better
     *                        the quality of the sample.
     * @param initialPosition initial position to start the estimation of radio
     *                        source position.
     * @param listener        listener in charge of attending events raised by this instance.
     * @throws IllegalArgumentException if quality scores is null, or length
     *                                  of quality scores is less than required minimum.
     */
    public PROMedSRobustRangingAndRssiRadioSourceEstimator2D(
            final double[] qualityScores, final Point2D initialPosition,
            final RobustRangingAndRssiRadioSourceEstimatorListener<S, Point2D> listener) {
        super(initialPosition, listener);
        internalSetQualityScores(qualityScores);
    }

    /**
     * Constructor.
     * Sets signal readings belonging to the same radio source.
     *
     * @param qualityScores   quality scores corresponding to each provided
     *                        sample. The larger the score value the better
     *                        the quality of the sample.
     * @param readings        signal readings belonging to the same radio source.
     * @param initialPosition initial position to start the estimation of radio
     *                        source position.
     * @param listener        listener in charge of attending events raised by this instance.
     * @throws IllegalArgumentException if readings are not valid, quality scores
     *                                  is null, or length of quality scores is less than required minimum.
     */
    public PROMedSRobustRangingAndRssiRadioSourceEstimator2D(
            final double[] qualityScores, final List<? extends RangingAndRssiReadingLocated<S, Point2D>> readings,
            final Point2D initialPosition,
            final RobustRangingAndRssiRadioSourceEstimatorListener<S, Point2D> listener) {
        super(readings, initialPosition, listener);
        internalSetQualityScores(qualityScores);
    }

    /**
     * Constructor.
     *
     * @param qualityScores              quality scores corresponding to each provided
     *                                   sample. The larger the score value the better
     *                                   the quality of the sample.
     * @param initialTransmittedPowerdBm initial transmitted power to start the
     *                                   estimation of radio source transmitted power
     *                                   (expressed in dBm's)
     * @throws IllegalArgumentException if quality scores is null, or length
     *                                  of quality scores is less than required minimum.
     */
    public PROMedSRobustRangingAndRssiRadioSourceEstimator2D(
            final double[] qualityScores, final Double initialTransmittedPowerdBm) {
        super(initialTransmittedPowerdBm);
        internalSetQualityScores(qualityScores);
    }

    /**
     * Constructor.
     * Sets signal readings belonging to the same radio source.
     *
     * @param qualityScores              quality scores corresponding to each provided
     *                                   sample. The larger the score value the better
     *                                   the quality of the sample.
     * @param readings                   signal readings belonging to the same radio source.
     * @param initialTransmittedPowerdBm initial transmitted power to start the
     *                                   estimation of radio source transmitted power
     *                                   (expressed in dBm's)
     * @throws IllegalArgumentException if readings are not valid, quality scores
     *                                  is null, or length of quality scores is less than required minimum.
     */
    public PROMedSRobustRangingAndRssiRadioSourceEstimator2D(
            final double[] qualityScores, final List<? extends RangingAndRssiReadingLocated<S, Point2D>> readings,
            final Double initialTransmittedPowerdBm) {
        super(readings, initialTransmittedPowerdBm);
        internalSetQualityScores(qualityScores);
    }

    /**
     * Constructor.
     *
     * @param qualityScores              quality scores corresponding to each provided
     *                                   sample. The larger the score value the better
     *                                   the quality of the sample.
     * @param initialTransmittedPowerdBm initial transmitted power to start the
     *                                   estimation of radio source transmitted power
     *                                   (expressed in dBm's)
     * @param listener                   listener in charge of attending events raised by this instance.
     * @throws IllegalArgumentException if quality scores is null, or length
     *                                  of quality scores is less than required minimum.
     */
    public PROMedSRobustRangingAndRssiRadioSourceEstimator2D(
            final double[] qualityScores, final Double initialTransmittedPowerdBm,
            final RobustRangingAndRssiRadioSourceEstimatorListener<S, Point2D> listener) {
        super(initialTransmittedPowerdBm, listener);
        internalSetQualityScores(qualityScores);
    }

    /**
     * Constructor.
     * Sets signal readings belonging to the same radio source.
     *
     * @param qualityScores              quality scores corresponding to each provided
     *                                   sample. The larger the score value the better
     *                                   the quality of the sample.
     * @param readings                   signal readings belonging to the same radio source.
     * @param initialTransmittedPowerdBm initial transmitted power to start the
     *                                   estimation of radio source transmitted power
     *                                   (expressed in dBm's)
     * @param listener                   listener in charge of attending events raised by this instance.
     * @throws IllegalArgumentException if readings are not valid, quality scores
     *                                  is null, or length of quality scores is less than required minimum.
     */
    public PROMedSRobustRangingAndRssiRadioSourceEstimator2D(
            final double[] qualityScores, final List<? extends RangingAndRssiReadingLocated<S, Point2D>> readings,
            final Double initialTransmittedPowerdBm,
            final RobustRangingAndRssiRadioSourceEstimatorListener<S, Point2D> listener) {
        super(readings, initialTransmittedPowerdBm, listener);
        internalSetQualityScores(qualityScores);
    }

    /**
     * Constructor.
     * Sets signal readings belonging to the same radio source.
     *
     * @param qualityScores              quality scores corresponding to each provided
     *                                   sample. The larger the score value the better
     *                                   the quality of the sample.
     * @param readings                   signal readings belonging to the same radio source.
     * @param initialPosition            initial position to start the estimation of radio
     *                                   source position.
     * @param initialTransmittedPowerdBm initial transmitted power to start the
     *                                   estimation of radio source transmitted power
     *                                   (expressed in dBm's).
     * @throws IllegalArgumentException if readings are not valid, quality scores
     *                                  is null, or length of quality scores is less than required minimum.
     */
    public PROMedSRobustRangingAndRssiRadioSourceEstimator2D(
            final double[] qualityScores, final List<? extends RangingAndRssiReadingLocated<S, Point2D>> readings,
            final Point2D initialPosition, final Double initialTransmittedPowerdBm) {
        super(readings, initialPosition, initialTransmittedPowerdBm);
        internalSetQualityScores(qualityScores);
    }

    /**
     * Constructor.
     *
     * @param qualityScores              quality scores corresponding to each provided
     *                                   sample. The larger the score value the better
     *                                   the quality of the sample.
     * @param initialPosition            initial position to start the estimation of radio
     *                                   source position.
     * @param initialTransmittedPowerdBm initial transmitted power to start the
     *                                   estimation of radio source transmitted power
     *                                   (expressed in dBm's).
     * @throws IllegalArgumentException if quality scores is null, or length
     *                                  of quality scores is less than required minimum.
     */
    public PROMedSRobustRangingAndRssiRadioSourceEstimator2D(
            final double[] qualityScores, final Point2D initialPosition, final Double initialTransmittedPowerdBm) {
        super(initialPosition, initialTransmittedPowerdBm);
        internalSetQualityScores(qualityScores);
    }

    /**
     * Constructor.
     *
     * @param qualityScores              quality scores corresponding to each provided
     *                                   sample. The larger the score value the better
     *                                   the quality of the sample.
     * @param initialPosition            initial position to start the estimation of radio
     *                                   source position.
     * @param initialTransmittedPowerdBm initial transmitted power to start the
     *                                   estimation of radio source transmitted power
     *                                   (expressed in dBm's).
     * @param listener                   in charge of attending events raised by this instance.
     * @throws IllegalArgumentException if quality scores is null, or length
     *                                  of quality scores is less than required minimum.
     */
    public PROMedSRobustRangingAndRssiRadioSourceEstimator2D(
            final double[] qualityScores, final Point2D initialPosition, final Double initialTransmittedPowerdBm,
            final RobustRangingAndRssiRadioSourceEstimatorListener<S, Point2D> listener) {
        super(initialPosition, initialTransmittedPowerdBm, listener);
        internalSetQualityScores(qualityScores);
    }

    /**
     * Constructor.
     * Sets signal readings belonging to the same radio source.
     *
     * @param qualityScores              quality scores corresponding to each provided
     *                                   sample. The larger the score value the better
     *                                   the quality of the sample.
     * @param readings                   signal readings belonging to the same radio source.
     * @param initialPosition            initial position to start the estimation of radio
     *                                   source position.
     * @param initialTransmittedPowerdBm initial transmitted power to start the
     *                                   estimation of radio source transmitted power
     *                                   (expressed in dBm's).
     * @param listener                   listener in charge of attending events raised by this instance.
     * @throws IllegalArgumentException if readings are not valid, quality scores
     *                                  is null, or length of quality scores is less than required minimum.
     */
    public PROMedSRobustRangingAndRssiRadioSourceEstimator2D(
            final double[] qualityScores, final List<? extends RangingAndRssiReadingLocated<S, Point2D>> readings,
            final Point2D initialPosition, final Double initialTransmittedPowerdBm,
            final RobustRangingAndRssiRadioSourceEstimatorListener<S, Point2D> listener) {
        super(readings, initialPosition, initialTransmittedPowerdBm, listener);
        internalSetQualityScores(qualityScores);
    }

    /**
     * Constructor.
     * Sets signal readings belonging to the same radio source.
     *
     * @param qualityScores              quality scores corresponding to each provided
     *                                   sample. The larger the score value the better
     *                                   the quality of the sample.
     * @param readings                   signal readings belonging to the same radio source.
     * @param initialPosition            initial position to start the estimation of radio
     *                                   source position.
     * @param initialTransmittedPowerdBm initial transmitted power to start the
     *                                   estimation of radio source transmitted power
     *                                   (expressed in dBm's).
     * @param initialPathLossExponent    initial path loss exponent. A typical value is 2.0.
     * @throws IllegalArgumentException if readings are not valid, quality scores
     *                                  is null, or length of quality scores is less than required minimum.
     */
    public PROMedSRobustRangingAndRssiRadioSourceEstimator2D(
            final double[] qualityScores, final List<? extends RangingAndRssiReadingLocated<S, Point2D>> readings,
            final Point2D initialPosition, final Double initialTransmittedPowerdBm,
            final double initialPathLossExponent) {
        super(readings, initialPosition, initialTransmittedPowerdBm, initialPathLossExponent);
        internalSetQualityScores(qualityScores);
    }

    /**
     * Constructor.
     *
     * @param qualityScores              quality scores corresponding to each provided
     *                                   sample. The larger the score value the better
     *                                   the quality of the sample.
     * @param initialPosition            initial position to start the estimation of radio
     *                                   source position.
     * @param initialTransmittedPowerdBm initial transmitted power to start the
     *                                   estimation of radio source transmitted power
     *                                   (expressed in dBm's).
     * @param initialPathLossExponent    initial path loss exponent. A typical value is 2.0.
     */
    public PROMedSRobustRangingAndRssiRadioSourceEstimator2D(
            final double[] qualityScores, final Point2D initialPosition, final Double initialTransmittedPowerdBm,
            final double initialPathLossExponent) {
        super(initialPosition, initialTransmittedPowerdBm, initialPathLossExponent);
        internalSetQualityScores(qualityScores);
    }

    /**
     * Constructor.
     *
     * @param qualityScores              quality scores corresponding to each provided
     *                                   sample. The larger the score value the better
     *                                   the quality of the sample.
     * @param initialPosition            initial position to start the estimation of radio
     *                                   source position.
     * @param initialTransmittedPowerdBm initial transmitted power to start the
     *                                   estimation of radio source transmitted power
     *                                   (expressed in dBm's).
     * @param initialPathLossExponent    initial path loss exponent. A typical value is 2.0.
     * @param listener                   listener in charge of attending events raised by this instance.
     */
    public PROMedSRobustRangingAndRssiRadioSourceEstimator2D(
            final double[] qualityScores, final Point2D initialPosition, final Double initialTransmittedPowerdBm,
            final double initialPathLossExponent,
            final RobustRangingAndRssiRadioSourceEstimatorListener<S, Point2D> listener) {
        super(initialPosition, initialTransmittedPowerdBm, initialPathLossExponent, listener);
        internalSetQualityScores(qualityScores);
    }

    /**
     * Constructor.
     * Sets signal readings belonging to the same radio source.
     *
     * @param qualityScores              quality scores corresponding to each provided
     *                                   sample. The larger the score value the better
     *                                   the quality of the sample.
     * @param readings                   signal readings belonging to the same radio source.
     * @param initialPosition            initial position to start the estimation of radio
     *                                   source position.
     * @param initialTransmittedPowerdBm initial transmitted power to start the
     *                                   estimation of radio source transmitted power
     *                                   (expressed in dBm's).
     * @param initialPathLossExponent    initial path loss exponent. A typical value is 2.0.
     * @param listener                   listener in charge of attending events raised by this instance.
     * @throws IllegalArgumentException if readings are not valid, quality scores
     *                                  is null, or length of quality scores is less than required minimum.
     */
    public PROMedSRobustRangingAndRssiRadioSourceEstimator2D(
            final double[] qualityScores, final List<? extends RangingAndRssiReadingLocated<S, Point2D>> readings,
            final Point2D initialPosition, final Double initialTransmittedPowerdBm,
            final double initialPathLossExponent,
            final RobustRangingAndRssiRadioSourceEstimatorListener<S, Point2D> listener) {
        super(readings, initialPosition, initialTransmittedPowerdBm, initialPathLossExponent, listener);
        internalSetQualityScores(qualityScores);
    }

    /**
     * Returns threshold to be used to keep the algorithm iterating in case that
     * best estimated threshold using median of residuals is not small enough.
     * Once a solution is found that generates a threshold below this value, the
     * algorithm will stop.
     * The stop threshold can be used to prevent the LMedS algorithm to iterate
     * too many times in cases where samples have a very similar accuracy.
     * For instance, in cases where proportion of outliers is very small (close
     * to 0%), and samples are very accurate (i.e. 1e-6), the algorithm would
     * iterate for a long time trying to find the best solution when indeed
     * there is no need to do that if a reasonable threshold has already been
     * reached.
     * Because of this behaviour the stop threshold can be set to a value much
     * lower than the one typically used in RANSAC, and yet the algorithm could
     * still produce even smaller thresholds in estimated results.
     *
     * @return stop threshold to stop the algorithm prematurely when a certain
     * accuracy has been reached.
     */
    public double getStopThreshold() {
        return stopThreshold;
    }

    /**
     * Sets threshold to be used to keep the algorithm iterating in case that
     * best estimated threshold using median of residuals is not small enough.
     * Once a solution is found that generates a threshold below this value,
     * the algorithm will stop.
     * The stop threshold can be used to prevent the LMedS algorithm to iterate
     * too many times in cases where samples have a very similar accuracy.
     * For instance, in cases where proportion of outliers is very small (close
     * to 0%), and samples are very accurate (i.e. 1e-6), the algorithm would
     * iterate for a long time trying to find the best solution when indeed
     * there is no need to do that if a reasonable threshold has already been
     * reached.
     * Because of this behaviour the stop threshold can be set to a value much
     * lower than the one typically used in RANSAC, and yet the algorithm could
     * still produce even smaller thresholds in estimated results.
     *
     * @param stopThreshold stop threshold to stop the algorithm prematurely
     *                      when a certain accuracy has been reached.
     * @throws IllegalArgumentException if provided value is zero or negative.
     * @throws LockedException          if this solver is locked.
     */
    public void setStopThreshold(final double stopThreshold) throws LockedException {
        if (isLocked()) {
            throw new LockedException();
        }
        if (stopThreshold <= MIN_STOP_THRESHOLD) {
            throw new IllegalArgumentException();
        }

        this.stopThreshold = stopThreshold;
    }

    /**
     * Returns quality scores corresponding to each pair of
     * positions and distances (i.e. sample).
     * The larger the score value the better the quality of the sample.
     * This implementation always returns null.
     * Subclasses using quality scores must implement proper behavior.
     *
     * @return quality scores corresponding to each sample.
     */
    @Override
    public double[] getQualityScores() {
        return qualityScores;
    }

    /**
     * Sets quality scores corresponding to each pair of positions and
     * distances (i.e. sample).
     * The larger the score value the better the quality of the sample.
     * This implementation makes no action.
     * Subclasses using quality scores must implement proper behaviour.
     *
     * @param qualityScores quality scores corresponding to each pair of
     *                      matched points.
     * @throws IllegalArgumentException if provided quality scores length
     *                                  is smaller than minimum required samples.
     * @throws LockedException          if robust solver is locked because an
     *                                  estimation is already in progress.
     */
    @Override
    public void setQualityScores(final double[] qualityScores) throws LockedException {
        if (isLocked()) {
            throw new LockedException();
        }
        internalSetQualityScores(qualityScores);
    }

    /**
     * Indicates whether solver is ready to find a solution.
     *
     * @return true if solver is ready, false otherwise.
     */
    @Override
    public boolean isReady() {
        return super.isReady() && qualityScores != null && qualityScores.length == readings.size();
    }

    /**
     * Robustly estimates position, transmitted power and path-loss exponent for a
     * radio source.
     *
     * @throws LockedException          if instance is busy during estimation.
     * @throws NotReadyException        if estimator is not ready.
     * @throws RobustEstimatorException if estimation fails for any reason
     *                                  (i.e. numerical instability, no solution available, etc).
     */
    @Override
    public void estimate() throws LockedException, NotReadyException, RobustEstimatorException {
        if (isLocked()) {
            throw new LockedException();
        }
        if (!isReady()) {
            throw new NotReadyException();
        }

        final var innerEstimator = new PROMedSRobustEstimator<>(
                new PROMedSRobustEstimatorListener<Solution<Point2D>>() {

                    @Override
                    public double[] getQualityScores() {
                        return qualityScores;
                    }

                    @Override
                    public double getThreshold() {
                        return stopThreshold;
                    }

                    @Override
                    public int getTotalSamples() {
                        return readings.size();
                    }

                    @Override
                    public int getSubsetSize() {
                        return Math.max(preliminarySubsetSize, getMinReadings());
                    }

                    @Override
                    public void estimatePreliminarSolutions(
                            final int[] samplesIndices, final List<Solution<Point2D>> solutions) {
                        solvePreliminarySolutions(samplesIndices, solutions);
                    }

                    @Override
                    public double computeResidual(final Solution<Point2D> currentEstimation, final int i) {
                        return residual(currentEstimation, i);
                    }

                    @Override
                    public boolean isReady() {
                        return PROMedSRobustRangingAndRssiRadioSourceEstimator2D.this.isReady();
                    }

                    @Override
                    public void onEstimateStart(final RobustEstimator<Solution<Point2D>> estimator) {
                        // no action needed
                    }

                    @Override
                    public void onEstimateEnd(final RobustEstimator<Solution<Point2D>> estimator) {
                        // no action needed
                    }

                    @Override
                    public void onEstimateNextIteration(
                            final RobustEstimator<Solution<Point2D>> estimator, final int iteration) {
                        if (listener != null) {
                            listener.onEstimateNextIteration(
                                    PROMedSRobustRangingAndRssiRadioSourceEstimator2D.this, iteration);
                        }
                    }

                    @Override
                    public void onEstimateProgressChange(
                            final RobustEstimator<Solution<Point2D>> estimator, final float progress) {
                        if (listener != null) {
                            listener.onEstimateProgressChange(
                                    PROMedSRobustRangingAndRssiRadioSourceEstimator2D.this, progress);
                        }
                    }
                });

        try {
            locked = true;

            if (listener != null) {
                listener.onEstimateStart(this);
            }

            inliersData = null;

            // inlier thresholds are disabled to obtain a less restrictive amount of inliers
            innerEstimator.setUseInlierThresholds(false);

            innerEstimator.setConfidence(confidence);
            innerEstimator.setMaxIterations(maxIterations);
            innerEstimator.setProgressDelta(progressDelta);
            final var result = innerEstimator.estimate();
            inliersData = innerEstimator.getInliersData();
            attemptRefine(result);

            if (listener != null) {
                listener.onEstimateEnd(this);
            }

        } catch (final com.irurueta.numerical.LockedException e) {
            throw new LockedException(e);
        } catch (final com.irurueta.numerical.NotReadyException e) {
            throw new NotReadyException(e);
        } finally {
            locked = false;
        }
    }

    /**
     * Returns method being used for robust estimation.
     *
     * @return method being used for robust estimation.
     */
    @Override
    public RobustEstimatorMethod getMethod() {
        return RobustEstimatorMethod.PROMEDS;
    }

    /**
     * Sets quality scores corresponding to each provided sample.
     * This method is used internally and does not check whether instance is
     * locked or not.
     *
     * @param qualityScores quality scores to be set.
     * @throws IllegalArgumentException if provided quality scores length
     *                                  is smaller than 3 samples.
     */
    private void internalSetQualityScores(final double[] qualityScores) {
        if (qualityScores == null || qualityScores.length < getMinReadings()) {
            throw new IllegalArgumentException();
        }

        this.qualityScores = qualityScores;
    }
}