from __future__ import division
import numpy as np
import matplotlib.pyplot as plt

def ICC(X):
    K = X.shape[1]
    m = X.mean(1)-X.mean()
    A = (m**2).mean()/X.var()
    A *= K/(K-1)
    A -= 1/(K-1)
    return A

def genplot(X, fname):

    n = X.shape[0]
    plt.clf()

    for i in range(1,n+1):
        plt.plot((i,i), (-2,2), '-', color='grey')
        plt.hold(True)

    for k in range(X.shape[1]):
        plt.plot(np.arange(1,n+1), X[:,k], 'o', color='blue')

    plt.xlim(0,n+1)
    plt.xlabel("Group number")
    plt.ylabel("Data value")

    icc = ICC(X)
    plt.title("ICC=%.2f" % icc)
    plt.xticks(range(1,n+1,2))

    plt.savefig(fname + ".png")
    plt.savefig(fname + ".svg")

X = np.random.uniform(low=-2, high=2, size=(20,4))
genplot(X, "ICC-example1")

V = np.random.uniform(low=-2, high=2, size=20)
X = np.zeros((20,4))
for i in range(len(V)):
    e = min(min(V[i]+2,2-V[i]),0.7)
    X[i,:] = np.random.uniform(low=V[i]-e, high=V[i]+e, size=4)
genplot(X, "ICC-example2")