chore: import upstream snapshot with attribution

mla/svm/kernerls.py

@@ -0,0 +1,35 @@
+# coding:utf-8
+import numpy as np
+import scipy.spatial.distance as dist
+
+
+class Linear(object):
+    def __call__(self, x, y):
+        return np.dot(x, y.T)
+
+    def __repr__(self):
+        return "Linear kernel"
+
+
+class Poly(object):
+    def __init__(self, degree=2):
+        self.degree = degree
+
+    def __call__(self, x, y):
+        return np.dot(x, y.T) ** self.degree
+
+    def __repr__(self):
+        return "Poly kernel"
+
+
+class RBF(object):
+    def __init__(self, gamma=0.1):
+        self.gamma = gamma
+
+    def __call__(self, x, y):
+        x = np.atleast_2d(x)
+        y = np.atleast_2d(y)
+        return np.exp(-self.gamma * dist.cdist(x, y) ** 2).flatten()
+
+    def __repr__(self):
+        return "RBF kernel"