Initial commit

Divers/descente_gradient/gradient.py

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+from mpl_toolkits.mplot3d import Axes3D
+from matplotlib import cm
+from matplotlib.colors import LogNorm
+import matplotlib.pyplot as plt
+import numpy as np
+import math
+
+def fonction(X, Y):
+    return X*np.exp(-X**2-Y**2)+(X**2+Y**2)/20
+
+def gradient_fonction(X, Y):
+    g_x=np.exp(-X**2-Y**2)+X*-2*X*np.exp(-X**2-Y**2)+X/10
+    g_y=-2*Y*X*np.exp(-X**2-Y**2)+Y/10
+    return g_x, g_y
+
+fig=plt.figure()
+fig.set_size_inches(9, 7, forward=True)
+ax=Axes3D(fig, azim=-29, elev=49)
+X=np.arange(-3, 3, 0.2)
+Y=np.arange(-3, 3, 0.2)
+X, Y=np.meshgrid(X, Y)
+Z=fonction(X, Y)
+ax.plot_surface(X, Y, Z, rstride=1, cstride=1)
+plt.xlabel("Paramètre 1 (x)")
+plt.ylabel("Paramètre 2 (y)")
+
+x, y=np.meshgrid(np.arange(-3, 3, 0.2),
+                np.arange(-3, 3, 0.2))
+z=-1
+
+u, v=gradient_fonction(x, y)
+w=0
+ax.quiver(x, y, z, u, v, w, length=0.15, normalize=True, color='#333333')
+
+plt.show()