bhattacharyya.py

#!/usr/bin/env python3
# @file: bhattacharyya.py
# @auth: Sprax Lines
# @date: 2016-06-14 18:58:23 Tue 14 Jun

# bhattacharyya test
# From: https://gist.github.com/jstadler/c47861f3d86c40b82d4c

import math

h1 = [ 1, 2, 3, 4, 5, 6, 7, 8 ]
h2 = [ 6, 5, 4, 3, 2, 1, 0, 0 ]
h3 = [ 8, 7, 6, 5, 4, 3, 2, 1 ]
h4 = [ 1, 2, 3, 4, 4, 3, 2, 1 ]
h5 = [ 8, 8, 8, 8, 8, 8, 8, 8 ]

h = [ h1, h2, h3, h4, h5 ]


def mean(hist):
    mean = 0.0
    for i in hist:
        mean += i
    mean/= len(hist)
    return mean


def bhatta (hist1,  hist2):
    # calculate mean of hist1
    h1_ = mean(hist1)

    # calculate mean of hist2
    h2_ = mean(hist2)

    # calculate score
    score = 0
    for i in range(8):
        score += math.sqrt(hist1[i] * hist2[i])
    # print(h1_, h2_, score)
    score = math.sqrt(1 - (1 / math.sqrt(h1_*h2_*8*8)) * score)
    return score

# generate and output scores
scores = []
for i in range(len(h)):
    score = []
    for j in range(len(h)):
        score.append(bhatta(h[i],h[j]))
    scores.append(score)

for i in scores:
    print(i)