Advanced plotting#
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# UNCOMMENT FOR INTERACTIVE PLOTS
#%matplotlib notebook
import numpy as np
import pandas as pd
import matplotlib.pyplot as plt
from matplotlib import cm
def func(x, y):
"""
A nice looking mapping.
"""
r = (x ** 2 + y ** 2) ** 0.5
theta = np.where(r != 0.0, np.arccos(x / r) * np.sign(y), 0.0)
z = (1.0 / (r + 5.0) ** 0.5) * np.sin(2.0 * np.pi * r / 3.0) * np.cos(4 * theta)
return z
x = np.linspace(-3.0, 3.0, 101)
y = np.linspace(-3.0, 3.0, 101)
X, Y = np.meshgrid(x, y)
X
array([[-3. , -2.94, -2.88, ..., 2.88, 2.94, 3. ],
[-3. , -2.94, -2.88, ..., 2.88, 2.94, 3. ],
[-3. , -2.94, -2.88, ..., 2.88, 2.94, 3. ],
...,
[-3. , -2.94, -2.88, ..., 2.88, 2.94, 3. ],
[-3. , -2.94, -2.88, ..., 2.88, 2.94, 3. ],
[-3. , -2.94, -2.88, ..., 2.88, 2.94, 3. ]])
Y
array([[-3. , -3. , -3. , ..., -3. , -3. , -3. ],
[-2.94, -2.94, -2.94, ..., -2.94, -2.94, -2.94],
[-2.88, -2.88, -2.88, ..., -2.88, -2.88, -2.88],
...,
[ 2.88, 2.88, 2.88, ..., 2.88, 2.88, 2.88],
[ 2.94, 2.94, 2.94, ..., 2.94, 2.94, 2.94],
[ 3. , 3. , 3. , ..., 3. , 3. , 3. ]])
Z = func(X, Y)
/tmp/ipykernel_979424/389966453.py:6: RuntimeWarning: invalid value encountered in divide
theta = np.where(r != 0.0, np.arccos(x / r) * np.sign(y), 0.0)
fig = plt.figure(figsize=(8, 6))
ax = fig.add_subplot(1, 1, 1)
ax.set_aspect("equal")
cont = plt.contourf(X, Y, Z, 10, cmap=cm.jet)
cbar = plt.colorbar(cont)
cbar.set_label("Amplitude, $z$")
plt.xlabel("Position, $x$")
plt.ylabel("Position, $y$")
plt.contour(X, Y, Z, 10, colors="black")
plt.show()
