logitscale: add new example to illustrate logitscale

jb-leger · jb-leger · commit 4717b46d4aa8 · 2019-07-23T11:23:22.000+02:00
diff --git a/examples/scales/logit_demo.py b/examples/scales/logit_demo.py
@@ -0,0 +1,61 @@
+"""
+================
+Logit Demo
+================
+
+Examples of plots with logit axes.
+"""
+
+import numpy as np
+import matplotlib.pyplot as plt
+
+xmax = 10
+x = np.linspace(-xmax, xmax, 10000)
+cdf_norm = np.array([np.math.erf(w / np.sqrt(2)) / 2 + 1 / 2 for w in x])
+cdf_laplacian = np.array(
+    [1 / 2 * np.exp(w) if w < 0 else 1 - 1 / 2 * np.exp(-w) for w in x]
+)
+cdf_cauchy = 1 / np.pi * np.arctan(x) + 1 / 2
+
+fig, axs = plt.subplots(nrows=3, ncols=2, figsize=(6.4, 8.5))
+
+# Common part, for the example, we will do the same plots on all graphs
+for i in range(3):
+    for j in range(2):
+        axs[i, j].plot(x, cdf_norm, label=r"$\mathcal{N}$")
+        axs[i, j].plot(x, cdf_laplacian, label=r"$\mathcal{L}$")
+        axs[i, j].plot(x, cdf_cauchy, label="Cauchy")
+        axs[i, j].legend()
+        axs[i, j].grid()
+
+# First line, logitscale, with standard notation
+axs[0, 0].set(title="logit scale")
+axs[0, 0].set_yscale("logit")
+axs[0, 0].set_ylim(1e-5, 1 - 1e-5)
+
+axs[0, 1].set(title="logit scale")
+axs[0, 1].set_yscale("logit")
+axs[0, 1].set_xlim(0, xmax)
+axs[0, 1].set_ylim(0.8, 1 - 5e-3)
+
+# Second line, logitscale, with survival notation (with `use_overline`), and
+# other format display 1/2
+axs[1, 0].set(title="logit scale")
+axs[1, 0].set_yscale("logit", one_half="1/2", use_overline=True)
+axs[1, 0].set_ylim(1e-5, 1 - 1e-5)
+
+axs[1, 1].set(title="logit scale")
+axs[1, 1].set_yscale("logit", one_half="1/2", use_overline=True)
+axs[1, 1].set_xlim(0, xmax)
+axs[1, 1].set_ylim(0.8, 1 - 5e-3)
+
+# Third line, linear scale
+axs[2, 0].set(title="linear scale")
+axs[2, 0].set_ylim(0, 1)
+
+axs[2, 1].set(title="linear scale")
+axs[2, 1].set_xlim(0, xmax)
+axs[2, 1].set_ylim(0.8, 1)
+
+fig.tight_layout()
+plt.show()
