Exemplo n.º 1
0
def make_detectornoniondist(alphaType, incEnergy):
    incEnergy = incEnergy / 1000.0  # parameters fitted for an energy in keV

    # distribution was modeled for only energies around the peaks, so need to know
    # which peak to take parameters from
    c = 0
    d = 0
    loc = 0
    scale = 0
    if alphaType == 'gd':
        c = 2.602
        d = 1.289
        loc = 0.042 * incEnergy + 3093.0
        scale = 0.224 * incEnergy + 2678.0
    elif alphaType == 'cm1' or alphaType == 'cm2':
        c = 2.560
        d = 1.450
        loc = 0.146 * incEnergy + 2762.0
        scale = 0.116 * incEnergy + 2959.0

    lossbins = np.linspace(100000, 0, 100001)

    # parameters output energy loss in eV
    losses = burr.pdf(lossbins, c, d, loc, scale)

    mean = float(burr.stats(c, d, loc=loc, scale=scale, moments='m'))
    # return the loss and some additional information
    return (losses, mean)
#Generate random numbers:
r = bradford.rvs(c, size=1000)
#And compare the histogram:
ax.hist(r, density=True, histtype='stepfilled', alpha=0.2)
ax.legend(loc='best', frameon=False)
plt.show()

#burr Continuous distributions¶
from scipy.stats import burr
import matplotlib.pyplot as plt
import numpy as np

fig, ax = plt.subplots(1, 1)
#Calculate a few first moments:
c, d = 10.5, 4.3
mean, var, skew, kurt = burr.stats(c, d, moments='mvsk')
#Display the probability density function (pdf):
x = np.linspace(burr.ppf(0.01, c, d), burr.ppf(0.99, c, d), 100)
ax.plot(x, burr.pdf(x, c, d), 'r-', lw=5, alpha=0.6, label='burr pdf')
#Alternatively, the distribution object can be called (as a function) to fix the shape, location and scale parameters. This returns a “frozen” RV object holding the given parameters fixed.
#Freeze the distribution and display the frozen pdf:
rv = burr(c, d)
ax.plot(x, rv.pdf(x), 'k-', lw=2, label='frozen pdf')
#Check accuracy of cdf and ppf:
vals = burr.ppf([0.001, 0.5, 0.999], c, d)
np.allclose([0.001, 0.5, 0.999], burr.cdf(vals, c, d))
True
#Generate random numbers:
r = burr.rvs(c, d, size=1000)
#And compare the histogram:
ax.hist(r, density=True, histtype='stepfilled', alpha=0.2)