saddle.ipynb

Kernel: Unknown Kernel

# Plot saddle point in 2d
# https://nbviewer.jupyter.org/github/entiretydotai/Meetup-Content/blob/master/Neural_Network/7_Optimizers.ipynb


import numpy as np
import scipy.sparse
import matplotlib.pyplot as plt
import os
from matplotlib import colors as mcolors

try:
    import probml_utils as pml
except ModuleNotFoundError:
    %pip install -qq git+https://github.com/probml/probml-utils.git
    import probml_utils as pml

fig = plt.figure(figsize=(8, 8))
ax = fig.gca(projection="3d")
X = np.arange(-5, 5, 0.25)
Y = np.arange(-5, 5, 0.25)
X, Y = np.meshgrid(X, Y)
Z = X**2 - Y**2

ax.text2D(
    0, 0, "*", fontdict={"ha": "center", "va": "center", "family": "sans-serif", "fontweight": "bold", "fontsize": 20}
)
ax.text2D(0, 0.01, "Saddle Point", fontdict={"family": "sans-serif", "fontweight": "bold"})
ax.set_xlabel("$X$")
ax.set_ylabel("$Y$")
ax.set_zlabel(r"$Z$")
ax.plot_surface(X, Y, Z)  # color="red");
pml.savefig("saddle.pdf")
plt.show()