public void testNormalDist() throws MathException {
DistributionFactory f = DistributionFactory.newInstance();
NormalDistribution n = f.createNormalDistribution(0.0d, 1.0d);
double lastx = Double.NEGATIVE_INFINITY;
double nextx = Double.NEGATIVE_INFINITY;
for (int i=-100; i < 100; i++) {
nextx = i / 100d;
System.out.println(n.cumulativeProbability(lastx, nextx));
lastx = nextx;
}
}
public double[] normalDistBasic(double[] xarray, double mu) {
double[] yarray = new double[xarray.length];
double rad2pi = 2.50662827d;
for (int off = 0; off < yarray.length; off++) {
double x = xarray[off];
double ss = -1d * x * x / 2d;
yarray[off] = (-1f / rad2pi) * Math.exp(ss);
}
return yarray;
}
如果在网络上找不到合适的平均值和标准差,实现任意平均值和标准差应该很容易。