From 2c902e15e3d45d3b21ae0f86d59e6017755430e7 Mon Sep 17 00:00:00 2001
From: MIURA Yasuyuki <kokosabu@gmail.com>
Date: Wed, 15 Nov 2023 03:35:34 +0900
Subject: [PATCH 1/4] add step03/plot_surface.py

---
 step03/plot_surface.py | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)
 create mode 100644 step03/plot_surface.py

diff --git a/step03/plot_surface.py b/step03/plot_surface.py
new file mode 100644
index 0000000..e78ea2f
--- /dev/null
+++ b/step03/plot_surface.py
@@ -0,0 +1,21 @@
+import numpy as np
+import matplotlib.pyplot as plt
+
+
+X = np.array([[-2, -1, 0, 1, 2],
+              [-2, -1, 0, 1, 2],
+              [-2, -1, 0, 1, 2],
+              [-2, -1, 0, 1, 2],
+              [-2, -1, 0, 1, 2]])
+Y = np.array([[-2, -2, -2, -2, -2],
+              [-1, -1, -1, -1, -1],
+              [0, 0, 0, 0, 0],
+              [1, 1, 1, 1, 1],
+              [2, 2, 2, 2, 2]])
+Z = X ** 2 + Y ** 2
+
+ax = plt.axes(projection='3d')  # projection='3d'により3d用グラフを指定
+ax.plot_surface(X, Y, Z, cmap='jet')  # cmap='jet'によりグラフの色を指定
+ax.set_xlabel('x')
+ax.set_ylabel('y')
+plt.show()

From 87e1661cdcfb1db6d0c70e5558295522d8a987f1 Mon Sep 17 00:00:00 2001
From: MIURA Yasuyuki <kokosabu@gmail.com>
Date: Wed, 15 Nov 2023 03:47:41 +0900
Subject: [PATCH 2/4] update step03/plot_surface.py

---
 step03/plot_surface.py | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/step03/plot_surface.py b/step03/plot_surface.py
index e78ea2f..a5219e5 100644
--- a/step03/plot_surface.py
+++ b/step03/plot_surface.py
@@ -2,6 +2,7 @@
 import matplotlib.pyplot as plt
 
 
+# 5x5 ====================
 X = np.array([[-2, -1, 0, 1, 2],
               [-2, -1, 0, 1, 2],
               [-2, -1, 0, 1, 2],
@@ -19,3 +20,16 @@
 ax.set_xlabel('x')
 ax.set_ylabel('y')
 plt.show()
+
+# np.meshgrid() ====================
+x = np.arange(-2, 2, 0.1)
+y = np.arange(-2, 2, 0.1)
+
+X, Y = np.meshgrid(x, y)
+Z = X ** 2 + Y ** 2
+
+ax = plt.axes(projection='3d')
+ax.plot_surface(X, Y, Z, cmap='jet')
+ax.set_xlabel('x')
+ax.set_ylabel('y')
+plt.show()

From 92c7ade9f813c88785feb2073db7e5d0065d6d68 Mon Sep 17 00:00:00 2001
From: MIURA Yasuyuki <kokosabu@gmail.com>
Date: Wed, 15 Nov 2023 03:48:03 +0900
Subject: [PATCH 3/4] add step03/plot_contour.py

---
 step03/plot_contour.py | 14 ++++++++++++++
 1 file changed, 14 insertions(+)
 create mode 100644 step03/plot_contour.py

diff --git a/step03/plot_contour.py b/step03/plot_contour.py
new file mode 100644
index 0000000..7a897de
--- /dev/null
+++ b/step03/plot_contour.py
@@ -0,0 +1,14 @@
+import numpy as np
+import matplotlib.pyplot as plt
+
+x = np.arange(-2, 2, 0.1)
+y = np.arange(-2, 2, 0.1)
+
+X, Y = np.meshgrid(x, y)
+Z = X ** 2 + Y ** 2
+
+ax = plt.axes()
+ax.contour(X, Y, Z)
+ax.set_xlabel('x')
+ax.set_ylabel('y')
+plt.show()

From f1483b29716ffdd37ba4dae26cb94900c6c50f05 Mon Sep 17 00:00:00 2001
From: MIURA Yasuyuki <kokosabu@gmail.com>
Date: Wed, 15 Nov 2023 03:48:15 +0900
Subject: [PATCH 4/4] add step03/plot_norm.py

---
 step03/plot_norm.py | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)
 create mode 100644 step03/plot_norm.py

diff --git a/step03/plot_norm.py b/step03/plot_norm.py
new file mode 100644
index 0000000..779f38d
--- /dev/null
+++ b/step03/plot_norm.py
@@ -0,0 +1,35 @@
+import numpy as np
+import matplotlib.pyplot as plt
+
+def multivariate_normal(x, mu, cov):
+    det = np.linalg.det(cov)
+    inv = np.linalg.inv(cov)
+    D = len(x)
+    z = 1 / np.sqrt((2 * np.pi) ** D * det)
+    y = z * np.exp((x - mu).T @ inv @ (x - mu) / -2.0)
+    return y
+
+mu = np.array([0.5, -0.2])
+cov = np.array([[2.0, 0.3],
+                [0.3, 0.5]])
+
+x = y = np.arange(-5, 5, 0.1)
+X, Y = np.meshgrid(x, y)
+Z = np.zeros_like(X)
+
+for i in range(X.shape[0]):
+    for j in range(X.shape[1]):
+        x = np.array([X[i, j], Y[i, j]])
+        Z[i, j] = multivariate_normal(x, mu, cov)
+
+fig = plt.figure()
+ax1 = fig.add_subplot(1, 2, 1, projection='3d')  
+ax1.set_xlabel('x')
+ax1.set_ylabel('y')
+ax1.plot_surface(X, Y, Z, cmap='jet')
+
+ax2 = fig.add_subplot(1, 2, 2)
+ax2.set_xlabel('x')
+ax2.set_ylabel('y')
+ax2.contour(X, Y, Z)
+plt.show()