k-means-unsupervised-clustering-scratch

k-means-unsupervised-scratch

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+
+# coding: utf-8
+
+# In[1]:
+
+
+import numpy as np
+from matplotlib import pyplot as plt
+from sklearn.datasets import make_blobs
+
+
+# In[7]:
+
+
+X,y = make_blobs(n_samples=500, centers = 5)
+print X.shape,y.shape
+
+
+# In[8]:
+
+
+plt.figure(0)
+plt.grid("on")
+plt.scatter(X[:,0], X[:,1])
+plt.show()
+
+
+# In[40]:
+
+
+k = 5
+
+colors = ['green','red','blue','yellow','orange','pink']
+
+clusters = {}
+
+for kx in range(k):
+    centre = 10.0*(2*np.random.random((X.shape[1],)) -1)
+    points = []
+    cluster = {
+
+        'centre' : centre,
+        'points' : points,
+        'color' : colors[kx]
+    }
+    clusters[kx] = cluster
+
+print clusters
+
+
+# In[14]:
+
+
+def distance(v1,v2):
+    return np.sqrt(np.sum((v1-v2)**2))
+
+
+# In[43]:
+
+
+for ix in range(X.shape[0]):
+    dist = []
+    curr_x = X[ix]
+
+    for kx in range(k):
+        d = distance(curr_x, clusters[kx]['centre'])
+        dist.append(d)
+
+    current_cluster = np.argmin(dist)
+
+    clusters[current_cluster]['points'].append(curr_x)
+
+for kx in range(k):
+    pts = np.array(clusters[kx]['points'])
+
+    clusters[kx]['coords'] = pts
+
+plt.figure(0)
+plt.grid("on")
+
+for kx in range(k):
+    pts = clusters[kx]['coords']
+
+    try:
+        plt.scatter(pts[:,0],pts[:,1], color = clusters[kx]['color'])
+    except:
+        pass
+
+    center = clusters[kx]['centre']
+    plt.scatter(center[0],center[1], color='black',s=100,marker="*")
+
+for kx in range(k):
+    if clusters[kx]['coords'].shape[0] > 0:
+        new_center = clusters[kx]['coords'].mean(axis=0)
+    else:
+        new_center = clusters[kx]['centre']
+
+    clusters[kx]['centre'] = new_center
+    clusters[kx]['points'] = []
+
+plt.figure(1)
+plt.grid("on")
+
+for kx in range(k):
+    pts = clusters[kx]['coords']
+
+    try:
+        plt.scatter(pts[:,0],pts[:,1], color = clusters[kx]['color'])
+    except:
+        pass
+
+    center = clusters[kx]['centre']
+    plt.scatter(center[0],center[1], color='black',s=100,marker="*")
+