Scatter plot of ternary problem in the simplex space

This example illustrates how to draw samples from the scores of a model and their true label.

# Author: Miquel Perello Nieto <miquel.perellonieto@bristol.ac.uk>
# License: new BSD

print(__doc__)

We generate 3 scores as comming from 3 Dirichlet distributions simulating the output scores of a classifier. Then we show how to draw the samples in the simplex space.

import matplotlib.pyplot as plt
import numpy as np
np.random.seed(42)

n_c1 = n_c2 = n_c3 = 300
p = np.concatenate((np.random.dirichlet([6, 2, 3], n_c1),
                    np.random.dirichlet([5, 12, 5], n_c2),
                    np.random.dirichlet([2, 3, 5], n_c3)
                   ))

y = np.concatenate((np.zeros(n_c1), np.ones(n_c2), np.ones(n_c3)*2))

from pycalib.visualisations.ternary import draw_tri_samples

fig, ax = draw_tri_samples(p, classes=y, alpha=0.6)

Here we specify the names of each class and change their colors.

fig, ax = draw_tri_samples(p, classes=y, alpha=0.6,
                           labels=['dogs', 'cats', 'fox'],
                           color_list=['saddlebrown', 'black', 'darkorange'])