List of usage examples for java.lang Math sqrt
@HotSpotIntrinsicCandidate public static double sqrt(double a)
From source file:eu.cassandra.utils.Utils.java
/** * This function is estimating the absolute euclidean distance of the active * and reactive power vector distance of two points of interest in the form of * arrays.//from w ww.ja va 2 s. c o m * * @param a1 * The first array of values * @param a2 * The second array of values * * @return the estimated absolute euclidean distance. */ public static double absoluteEuclideanDistance(double[] a1, double[] a2) { return Math.sqrt(Math.pow(a1[0] - a2[0], 2) + Math.pow(a1[1] - a2[1], 2)); }
From source file:hivemall.utils.math.StatsUtils.java
/** * @return value of probabilistic density function *//*from w w w . ja v a2 s .c o m*/ public static double pdf(final double x, final double x_hat, final double sigma) { if (sigma == 0.d) { return 0.d; } double diff = x - x_hat; double numerator = Math.exp(-0.5d * diff * diff / sigma); double denominator = Math.sqrt(2.d * Math.PI) * Math.sqrt(sigma); return numerator / denominator; }
From source file:com.davidbracewell.math.distribution.NormalDistribution.java
@Override public double probability(double x) { return 1d / Math.sqrt(TWO_PI * var) * Math.exp(-Math.pow(x - mean, 2) / (2 * var)); }
From source file:net.sf.maltcms.chromaui.features.spi.FeatureTable.java
public static RealMatrix normalize(RealMatrix sourceMatrix, boolean center, boolean normalize) { RealMatrix normalized = MatrixUtils.createRealMatrix(sourceMatrix.getRowDimension(), sourceMatrix.getColumnDimension()); for (int col = 0; col < sourceMatrix.getColumnDimension(); col++) { double[] columnVector = sourceMatrix.getColumn(col); double mean = StatUtils.mean(columnVector); double stdev = Math.sqrt(StatUtils.variance(columnVector, mean)); Logger.getLogger(FeatureTable.class.getName()).log(Level.INFO, "column {0}, mean={1} stdev={2}", new Object[] { col, mean, stdev }); for (int j = 0; j < columnVector.length; j++) { normalized.setEntry(j, col, (sourceMatrix.getEntry(j, col) - mean) / stdev); }/*from w w w . j av a 2s .c om*/ } return normalized; }
From source file:com.itemanalysis.psychometrics.polycor.PearsonCorrelation.java
/** * Correct correlation for spuriousness. This method assumes that * the test item is Y and the test score is X. Used for the * point-biserial and biserial correlation in an item analysis. * * @return correlation corrected for spuriousness *//* ww w.j ava 2 s .c om*/ public Double correctedValue() { double testSd = sdX.getResult(); double itemSd = sdY.getResult(); double rOld = this.value(); double denom = Math.sqrt(itemSd * itemSd + testSd * testSd - 2 * rOld * itemSd * testSd); if (denom == 0.0) return Double.NaN; return (rOld * testSd - itemSd) / denom; }
From source file:edu.illinois.cs.cogcomp.saul.test.TestReal.java
public static double getPearsonCorrelation(double[] scores1, double[] scores2) { double result; double sum_sq_x = 0; double sum_sq_y = 0; double sum_coproduct = 0; double mean_x = scores1[0]; double mean_y = scores2[0]; for (int i = 2; i < scores1.length + 1; i += 1) { double sweep = (double) (i - 1) / i; double delta_x = scores1[i - 1] - mean_x; double delta_y = scores2[i - 1] - mean_y; sum_sq_x += delta_x * delta_x * sweep; sum_sq_y += delta_y * delta_y * sweep; sum_coproduct += delta_x * delta_y * sweep; mean_x += delta_x / i;// ww w . java2 s . c om mean_y += delta_y / i; } double pop_sd_x = Math.sqrt(sum_sq_x / scores1.length); double pop_sd_y = Math.sqrt(sum_sq_y / scores1.length); double cov_x_y = sum_coproduct / scores1.length; result = cov_x_y / (pop_sd_x * pop_sd_y); return result; }
From source file:net.atos.ari.vital.taastrustcalculator.StatisticsCalculator.java
public boolean calculateNumericVariance(double[] values) { double alpha = 0.05; double mean = StatUtils.mean(values); double variance = StatUtils.variance(values); double expected = Math.pow(mean * 0.05, 2); //double expected = 0.01; double degFreedom = values.length - 1.0; double T = (degFreedom * variance) / expected; logger.debug("Mean = " + mean); logger.debug("Standard Deviation = " + Math.sqrt(variance)); logger.debug("Test Statistic calculated T = " + T); if (degFreedom <= 0) return false; ChiSquaredDistribution myDist = new ChiSquaredDistribution(degFreedom); double myTLeft = myDist.inverseCumulativeProbability(alpha / 2.0); double myTRight = myDist.inverseCumulativeProbability(1.0 - alpha / 2.0); logger.debug("Boundaries: " + myTLeft + " to " + myTRight); // Determine if z score is in the region of acceptance if ((myTLeft <= T) && (T <= myTRight)) { // H0 -> Variance of the data is equal to the expected one return true; }//from w ww. j av a 2 s .c o m // H1 -> Variance of the data is different to the expected one return false; }
From source file:Main.java
public static int computeInitialSampleSize(BitmapFactory.Options options, int minSideLength, int maxNumOfPixels) { double w = options.outWidth; double h = options.outHeight; int lowerBound = (maxNumOfPixels == -1) ? 1 : (int) Math.ceil(Math.sqrt(w * h / maxNumOfPixels)); int upperBound = (minSideLength == -1) ? 128 : (int) Math.min(Math.floor(w / minSideLength), Math.floor(h / minSideLength)); if (upperBound < lowerBound) { // return the larger one when there is no overlapping zone. return lowerBound; }/*from ww w . j ava 2s.c o m*/ if ((maxNumOfPixels == -1) && (minSideLength == -1)) { return 1; } else if (minSideLength == -1) { return lowerBound; } else { return upperBound; } }
From source file:com.google.location.lbs.gnss.gps.pseudorange.EcefToTopocentricConverter.java
/** * Transformation of {@code inputVectorMeters} with origin at {@code originECEFMeters} into * topocentric coordinate system. The result is {@code TopocentricAEDValues} containing azimuth * from north +ve clockwise, radians; elevation angle, radians; distance, vector length meters * * <p>Source: http://www.navipedia.net/index.php/Transformations_between_ECEF_and_ENU_coordinates * http://kom.aau.dk/~borre/life-l99/topocent.m * *//*from w ww. j av a2 s .c o m*/ public static TopocentricAEDValues convertCartesianToTopocentericRadMeters(final double[] originECEFMeters, final double[] inputVectorMeters) { GeodeticLlaValues latLngAlt = Ecef2LlaConverter.convertECEFToLLACloseForm(originECEFMeters[0], originECEFMeters[1], originECEFMeters[2]); RealMatrix rotationMatrix = Ecef2EnuConverter .getRotationMatrix(latLngAlt.latitudeRadians, latLngAlt.longitudeRadians).transpose(); double[] eastNorthUpVectorMeters = GpsMathOperations .matrixByColVectMultiplication(rotationMatrix.transpose().getData(), inputVectorMeters); double eastMeters = eastNorthUpVectorMeters[EAST_IDX]; double northMeters = eastNorthUpVectorMeters[NORTH_IDX]; double upMeters = eastNorthUpVectorMeters[UP_IDX]; // calculate azimuth, elevation and height from the ENU values double horizontalDistanceMeters = Math.hypot(eastMeters, northMeters); double azimuthRadians; double elevationRadians; if (horizontalDistanceMeters < MIN_DISTANCE_MAGNITUDE_METERS) { elevationRadians = Math.PI / 2.0; azimuthRadians = 0; } else { elevationRadians = Math.atan2(upMeters, horizontalDistanceMeters); azimuthRadians = Math.atan2(eastMeters, northMeters); } if (azimuthRadians < 0) { azimuthRadians += 2 * Math.PI; } double distanceMeters = Math.sqrt(Math.pow(inputVectorMeters[0], 2) + Math.pow(inputVectorMeters[1], 2) + Math.pow(inputVectorMeters[2], 2)); return new TopocentricAEDValues(elevationRadians, azimuthRadians, distanceMeters); }
From source file:com.xy.inc.service.impl.POIServiceImpl.java
@Override public List<POI> buscarPOISProximos(Integer coordenadaX, Integer coordenadaY, Integer distMax) throws ServiceException { try {//from w ww.java 2 s .co m List<POI> poiList = new ArrayList<>(); for (POI poi : poiRepository.findAll()) { if (Math.sqrt(Math.pow(coordenadaX - poi.getCoordenadaX(), 2) + Math.pow(coordenadaY - poi.getCoordenadaY(), 2)) <= 10) { poiList.add(poi); } } return poiList; } catch (Exception e) { throw new ServiceException("No foi possivel buscar os POIs proximos"); } }