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1 files changed, 27 insertions, 0 deletions

diff --git a/gauss_kernel.py b/gauss_kernel.py
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+++ b/gauss_kernel.py
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+import math
+import numpy as np
+from frob_norm import frob_norm
+
+
+def gauss_kernel(X_1, X_2, sigma):
+    """
+    Calculates the Gaussian Kernel.
+    X_1: first representations.
+    X_2: second representations.
+    sigma: kernel width.
+    """
+    x1_l = len(X_1)
+    x1_range = range(x1_l)
+    x2_l = len(X_2)
+    x2_range = range(x2_l)
+
+    inv_sigma = -0.5 / (sigma*sigma)
+
+    K = np.zeros((x1_l, x2_l))
+    for i in x1_range:
+        for j in x2_range:
+            f_norm = frob_norm(X_1[i] - X_2[j])
+            # print(f_norm)
+            K[i, j] = math.exp(inv_sigma * f_norm)
+
+    return K