from __future__ import division # In case someone wants to use Python 2 import numpy as np import matplotlib as mpl import matplotlib.pyplot as plt import seaborn as sns # Just for the colors  mpl.rcParams['axes.labelsize'] = 20 mpl.rcParams['axes.titlesize'] = 22 mpl.rcParams['legend.fontsize'] = 18 mpl.rcParams['xtick.labelsize'] = 14 mpl.rcParams['ytick.labelsize'] = 14 mpl.rcParams['lines.linewidth'] = 3  def dirichlet(n, x):     return np.where(x!=0, np.sin((n + .5)*x)/np.sin(.5*x), 2*n + 1)  points = 2**10 + 1 kernels = 4 x_min = -np.pi x_max = np.pi  x_vals = np.linspace(x_min, x_max, num=points) n_vals = np.arange(1, kernels + 1) D = dirichlet(np.resize(n_vals, (points, kernels)).T,               np.resize(x_vals, (kernels, points)))  fig = plt.figure() ax = fig.add_subplot(1, 1, 1) for kernel, n in zip(D, n_vals):     ax.plot(x_vals, kernel,             label=r'$\frac{\sin((' + str(n) + r'+1/2)x)}{\sin(x/2)}$')  ax.xaxis.set_ticks(np.pi*np.arange(-4, 5)/4) ax.xaxis.set_ticklabels([r'$-\pi$', r'$-\frac{3\pi}{4}$', r'$-\frac{\pi}{2}$',                          r'$-\frac{\pi}{4}$', r'$0$', r'$\frac{\pi}{4}$',                          r'$\frac{\pi}{2}$', r'$\frac{3\pi}{4}$', r'$\pi$']) ax.legend() ax.set_xlim([x_min, x_max]) ax.set_xlabel(r'$x$') ax.set_ylabel(r'$D_n(x)$') ax.xaxis.grid(color='gray') ax.yaxis.grid(color='gray') plt.tight_layout() plt.savefig('dirichlet.svg')