Java FastMath类代码示例

import net.jafama.FastMath; //导入依赖的package包/类
public void logicLoop(float calcX, float deltaX) {
	this.mouthCurvePos = this.parent.getPos().add(this.pos).addX(0.5f * this.size.x).addX(-calcX);
	this.mouthCurveTimer.logicLoop();
	float maxDelta = this.size.y * 0.5f * this.parent.getState().getMouthAmplitude();
	while (this.mouthCurveTimer.timeUp()) {
		this.mouthCurveTimer.reset();
		Vec newVec = new Vec(calcX, (float) (FastMath.tan(calcX * 10) * FastMath.sinQuick(calcX * 4) * FastMath.cosQuick(calcX * 0.5f) * maxDelta));
		if (newVec.y > maxDelta) {
			newVec = newVec.setY(maxDelta);
		}
		if (newVec.y < -maxDelta) {
			newVec = newVec.setY(-maxDelta);
		}
		this.mouthCurve.add(newVec);
	}
	Iterator<Vec> it = this.mouthCurve.iterator();
	while (it.hasNext()) {
		if (it.next().x <= calcX - this.size.x) {
			it.remove();
		} else {
			break;
		}
	}
}
 

import net.jafama.FastMath; //导入依赖的package包/类
@Override
   protected void transformInverse(int x, int y, float[] out) {
       float dx = x - icentreX;
       float dy = y - icentreY;
       float distance2 = dx * dx + dy * dy;
       if (distance2 > radius2) {
           out[0] = x;
           out[1] = y;
       } else {
           float distance = (float) Math.sqrt(distance2);
           float amount = amplitude * (float) FastMath.sin(distance / wavelength * ImageMath.TWO_PI - phase);
           amount *= (radius-distance)/radius;
		if ( distance != 0 ) {
               amount *= wavelength / distance;
           }
		out[0] = x + dx*amount;
		out[1] = y + dy*amount;
	}
}
 

import net.jafama.FastMath; //导入依赖的package包/类
@Override
  protected void transformInverse(int x, int y, float[] out) {
      double dx = x - icentreX;
      double dy = y - icentreY;
      double r = Math.sqrt(dx * dx + dy * dy);
      double theta = FastMath.atan2(dy, dx) - angle - angle2;
      theta = ImageMath.triangle((float) (theta / Math.PI * sides * .5));
      if (radius != 0) {
          double c = FastMath.cos(theta);
          double radiusc = radius / c;
          r = radiusc * ImageMath.triangle( (float)(r/radiusc) );
}
theta += angle;

      double zoomedR = r / zoom;
      out[0] = (float)(icentreX + zoomedR*FastMath.cos(theta));
      out[1] = (float)(icentreY + zoomedR*FastMath.sin(theta));
  }
 

import net.jafama.FastMath; //导入依赖的package包/类
@Override
protected void transformInverse(int x, int y, float[] out) {
    float dx = x - cx;
    float dy = cy - y;
    double r = Math.sqrt(dx * dx + dy * dy);

    double radius = srcHeight * zoom / 2;
    double angle = Utils.transformAtan2AngleToIntuitive(FastMath.atan2(dy, dx)) + rotateResult;

    if (angle > (2 * Math.PI)) {
        angle -= 2 * Math.PI;
    }
    float nx = (float) ((angle * srcWidth) / (2 * Math.PI));
    float ratio = (float) (r / radius);
    float correctedRatio = ImageMath.bias(ratio, innerZoom);
    float ny = correctedRatio * srcHeight;
    if(!inverted) {
        ny = srcHeight - ny;
    }

    out[0] = nx;
    out[1] = ny;
}
 

import net.jafama.FastMath; //导入依赖的package包/类
/**
 * Process an array of data
 * 
 * @param data data to process
 * @param kernel Kernel function to use.
 * @param epsilon Precision threshold
 */
public KernelDensityEstimator(double[] data, KernelDensityFunction kernel, double epsilon) {
  boolean needsort = false;
  for (int i = 1; i < data.length; i++) {
    if (data[i - 1] > data[i]) {
      needsort = true;
      break;
    }
  }
  // Duplicate and sort when needed:
  if (needsort) {
    data = data.clone();
    Arrays.sort(data);
  }
  final double min = data[0];
  final double max = data[data.length - 1];
  // Heuristic for choosing the window size.
  int windows = 1 + (int) (FastMath.log(data.length));

  process(data, min, max, kernel, windows, epsilon);
}
 

import net.jafama.FastMath; //导入依赖的package包/类
/**
 * Compute row pij[i], using binary search on the kernel bandwidth sigma to
 * obtain the desired perplexity.
 *
 * @param i Current point
 * @param pij_row Distance matrix row pij[i]
 * @param perplexity Desired perplexity
 * @param log_perp Log of desired perplexity
 * @param pij_i Output row
 * @return beta
 */
protected static double computeSigma(int i, DoubleArray pij_row, double perplexity, double log_perp, double[] pij_i) {
  double max = pij_row.get((int) FastMath.ceil(perplexity)) / Math.E;
  double beta = 1 / max; // beta = 1. / (2*sigma*sigma)
  double diff = computeH(pij_row, pij_i, -beta) - log_perp;
  double betaMin = 0.;
  double betaMax = Double.POSITIVE_INFINITY;
  for(int tries = 0; tries < PERPLEXITY_MAXITER && Math.abs(diff) > PERPLEXITY_ERROR; ++tries) {
    if(diff > 0) {
      betaMin = beta;
      beta += (betaMax == Double.POSITIVE_INFINITY) ? beta : ((betaMax - beta) * .5);
    }
    else {
      betaMax = beta;
      beta -= (beta - betaMin) * .5;
    }
    diff = computeH(pij_row, pij_i, -beta) - log_perp;
  }
  return beta;
}
 

import net.jafama.FastMath; //导入依赖的package包/类
@Override
public double cdf(double x) {
  if(alpha <= 0.0 || beta <= 0.0 || Double.isNaN(alpha) || Double.isNaN(beta) || Double.isNaN(x)) {
    return Double.NaN;
  }
  if(x <= 0.0) {
    return 0.0;
  }
  if(x >= 1.0) {
    return 1.0;
  }
  if(alpha > SWITCH && beta > SWITCH) {
    return regularizedIncBetaQuadrature(alpha, beta, x);
  }
  double bt = FastMath.exp(-logbab + alpha * FastMath.log(x) + beta * FastMath.log1p(-x));
  if(x < (alpha + 1.0) / (alpha + beta + 2.0)) {
    return bt * regularizedIncBetaCF(alpha, beta, x) / alpha;
  }
  else {
    return 1.0 - bt * regularizedIncBetaCF(beta, alpha, 1.0 - x) / beta;
  }
}
 

import net.jafama.FastMath; //导入依赖的package包/类
@Override
public <A> double estimate(A data, NumberArrayAdapter<?, ? super A> adapter, final int end) {
  final int begin = countLeadingZeros(data, adapter, end);
  final int k = end - begin;
  if(k < 2) {
    throw new ArithmeticException("ID estimates require at least 2 non-zero distances");
  }
  final int n1 = k >> 1; // i in Section 5.1 of the ACM publication
  final int n2 = (3 * k) >> 2; // j in Section 5.1 of the ACM publication
  final int n3 = k; // n in Section 5.1 of the ACM publication
  final double r1 = adapter.getDouble(data, begin + n1 - 1);
  final double r2 = adapter.getDouble(data, begin + n2 - 1);
  final double r3 = adapter.getDouble(data, begin + n3 - 1);
  final double p = (r3 - r2) / (r1 - 2 * r2 + r3);
  // Optimized away: final double a1 = 1;
  final double a2 = (1. - p) / p;
  return (/* a1 * */ FastMath.log(n3 / (double) n2) //
      + a2 * FastMath.log(n1 / (double) n2)) / (/* a1 * */ FastMath.log(r3 / r2) + a2 * FastMath.log(r1 / r2));
}
 

import net.jafama.FastMath; //导入依赖的package包/类
/**
 * Cumulative probability density function (CDF) of a normal distribution.
 * 
 * Reference:
 * <p>
 * G. Marsaglia<br />
 * Evaluating the Normal Distribution<br />
 * Journal of Statistical Software 11(4)
 * </p>
 *
 * @param x value to evaluate CDF at
 * @param mu Mean value
 * @param sigma Standard deviation.
 * @return The CDF of the given normal distribution at x.
 */
@Reference(authors = "G. Marsaglia", //
    title = "Evaluating the Normal Distribution", //
    booktitle = "Journal of Statistical Software 11(4)", //
    url = "https://www.jstatsoft.org/article/view/v011i04/v11i04.pdf")
public static double cdf(double x, double mu, double sigma) {
  x = (x - mu) / sigma;
  if(x >= 8.22) {
    return 1.;
  }
  if(x <= -8.22) {
    return 0.;
  }
  if(x != x) {
    return Double.NaN;
  }
  double s = x, t = 0, b = x, q = x * x, i = 1;
  while(s != t && i < 1000) {
    t = s;
    s += (b *= q / (i += 2));
  }
  // Constant is 0.5 * log(2*pi)
  return .5 + s * FastMath.exp(-.5 * q - .91893853320467274178);
}
 

import net.jafama.FastMath; //导入依赖的package包/类
@Reference(authors = "D. W. Scott", title = "Multivariate density estimation: Theory, Practice, and Visualization", //
    booktitle = "Multivariate Density Estimation: Theory, Practice, and Visualization", //
    url = "http://dx.doi.org/10.1002/9780470316849")
private double[] initializeBandwidth(double[][] data) {
  MeanVariance mv0 = new MeanVariance();
  MeanVariance mv1 = new MeanVariance();
  // For Kernel bandwidth.
  for(double[] projected : data) {
    mv0.put(projected[0]);
    mv1.put(projected[1]);
  }
  // Set bandwidths according to Scott's rule:
  // Note: in projected space, d=2.
  double[] bandwidth = new double[2];
  bandwidth[0] = MathUtil.SQRT5 * mv0.getSampleStddev() * FastMath.pow(rel.size(), -1 / 6.);
  bandwidth[1] = MathUtil.SQRT5 * mv1.getSampleStddev() * FastMath.pow(rel.size(), -1 / 6.);
  return bandwidth;
}
 

import net.jafama.FastMath; //导入依赖的package包/类
/**
 * Provides a new CorrelationAnalysisSolution holding the specified matrix and
 * number format.
 * 
 * @param solution the linear equation system describing the solution
 *        equations
 * @param db the database containing the objects
 * @param strongEigenvectors the strong eigenvectors of the hyperplane induced
 *        by the correlation
 * @param weakEigenvectors the weak eigenvectors of the hyperplane induced by
 *        the correlation
 * @param similarityMatrix the similarity matrix of the underlying distance
 *        computations
 * @param centroid the centroid if the objects belonging to the hyperplane
 *        induced by the correlation
 * @param nf the number format for output accuracy
 */
public CorrelationAnalysisSolution(LinearEquationSystem solution, Relation<V> db, double[][] strongEigenvectors, double[][] weakEigenvectors, double[][] similarityMatrix, double[] centroid, NumberFormat nf) {
  this.linearEquationSystem = solution;
  this.correlationDimensionality = strongEigenvectors[0].length;
  this.strongEigenvectors = strongEigenvectors;
  this.weakEigenvectors = weakEigenvectors;
  this.similarityMatrix = similarityMatrix;
  this.centroid = centroid;
  this.nf = nf;

  // determine standard deviation
  double variance = 0;
  DBIDs ids = db.getDBIDs();
  for(DBIDIter iter = ids.iter(); iter.valid(); iter.advance()) {
    double distance = distance(db.get(iter).toArray());
    variance += distance * distance;
  }
  standardDeviation = FastMath.sqrt(variance / ids.size());
}
 

import net.jafama.FastMath; //导入依赖的package包/类
@Override
public double[] ecefToLatLngRadHeight(double x, double y, double z) {
  double lng = FastMath.atan2(y, x);
  final double p = FastMath.sqrt(x * x + y * y);
  double plat = FastMath.atan2(z, p * (1 - esq));
  double h = 0;

  // Iteratively improving the lat value
  // TODO: instead of a fixed number of iterations, check for convergence?
  for (int i = 0;; i++) {
    final double slat = FastMath.sin(plat);
    final double v = a / FastMath.sqrt(1 - esq * slat * slat);
    double lat = FastMath.atan2(z + esq * v * slat, p);
    if (Math.abs(lat - plat) < PRECISION || i > MAX_ITER) {
      h = p / FastMath.cos(lat) - v;
      return new double[] { lat, lng, h };
    }
    plat = lat;
  }
}
 

import net.jafama.FastMath; //导入依赖的package包/类
@Override
public <A, B> double dependence(NumberArrayAdapter<?, A> adapter1, A data1, NumberArrayAdapter<?, B> adapter2, B data2) {
  final int len = size(adapter1, data1, adapter2, data2);
  // Find a number of bins as recommended by Cheng et al.
  double p = MathUtil.log2(len / (double) TARGET);
  // As we are in 2d, take the root (*.5) But let's use at least 1, too.
  // Check: for 10000 this should give 4, for 150 it gives 1.
  int power = Math.max(1, (int) Math.floor(p * .5));
  int gridsize = 1 << power;
  double loggrid = FastMath.log((double) gridsize);

  ArrayList<int[]> parts1 = buildPartitions(adapter1, data1, len, power);
  ArrayList<int[]> parts2 = buildPartitions(adapter2, data2, len, power);

  int[][] res = new int[gridsize][gridsize];
  intersectionMatrix(res, parts1, parts2, gridsize);
  return 1. - getMCEntropy(res, parts1, parts2, len, gridsize, loggrid);
}
 

import net.jafama.FastMath; //导入依赖的package包/类
/**
 * Poisson distribution probability, but also for non-integer arguments.
 *
 * lb^x exp(-lb) / x!
 *
 * @param x X
 * @param lambda lambda
 * @return Poisson distribution probability
 */
public static double rawProbability(double x, double lambda) {
  // Extreme lambda
  if(lambda == 0) {
    return ((x == 0) ? 1. : 0.);
  }
  // Extreme values
  if(Double.isInfinite(lambda) || x < 0) {
    return 0.;
  }
  if(x <= lambda * Double.MIN_NORMAL) {
    return FastMath.exp(-lambda);
  }
  if(lambda < x * Double.MIN_NORMAL) {
    double r = -lambda + x * FastMath.log(lambda) - GammaDistribution.logGamma(x + 1);
    return FastMath.exp(r);
  }
  final double f = MathUtil.TWOPI * x;
  final double y = -stirlingError(x) - devianceTerm(x, lambda);
  return FastMath.exp(y) / FastMath.sqrt(f);
}
 

import net.jafama.FastMath; //导入依赖的package包/类
/**
 * Normalizes the columns of this matrix to length of 1.0.
 *
 * Note: if a column has length 0, it will remain unmodified.
 *
 * @param m1 Input matrix
 */
public static void normalizeColumns(final double[][] m1) {
  final int columndimension = getColumnDimensionality(m1);
  for(int col = 0; col < columndimension; col++) {
    double norm = 0.0;
    for(int row = 0; row < m1.length; row++) {
      final double v = m1[row][col];
      norm += v * v;
    }
    if(norm > 0) {
      norm = FastMath.sqrt(norm);
      for(int row = 0; row < m1.length; row++) {
        m1[row][col] /= norm;
      }
    }
  }
}