Feature add cosine proximity loss

neural_nets/losses/losses.py

@@ -1,7 +1,7 @@
 from abc import ABC, abstractmethod
 
 import numpy as np
-from tests import assert_is_binary, assert_is_stochastic
+# from tests import assert_is_binary, assert_is_stochastic
 
 
 class ObjectiveBase(ABC):
@@ -385,3 +385,66 @@ def grad(self, Y_fake, module, Y_real=None, gradInterp=None):
         else:
             raise ValueError("Unrecognized module: {}".format(module))
         return grad
+
+
+class Cosine(ObjectiveBase):
+    def __init__(self):
+        super().__init__()
+
+    def __call__(self, y, y_pred):
+        return self.loss(y, y_pred)
+
+    def __str__(self):
+        return "Cosine Proximity"
+
+    @staticmethod
+    def loss(y, y_pred):
+        """
+        Compute the Cosine distance between 1-D arrays.
+
+        The Cosine distance between `u` and `v`, is defined as
+        .. math::
+            1 - \\frac{u \\cdot v}
+                      {||u||_2 ||v||_2}.
+        where :math:`u \\cdot v` is the dot product of :math:`u` and
+        :math:`v`.
+
+        Parameters
+        ----------
+        y : numpy array of shape (n, m)
+
+        y_pred : numpy array of shape (n, m)
+
+
+        Returns
+        -------
+        loss : float
+
+        """
+        def l2_normalize(x, axis=-1):
+            y = np.max(np.sum(x ** 2, axis, keepdims=True), axis, keepdims=True)
+            return x / np.sqrt(y)
+
+        y_true = l2_normalize(y, axis=-1)
+        y_pred = l2_normalize(y_pred, axis=-1)
+        return 1. - np.sum(y_true * y_pred, axis=-1)
+
+    @staticmethod
+    def grad(y, y_pred, z, act_fn):
+        """
+
+
+        Parameters
+        ----------
+        y : numpy array of shape (n, m)
+
+        y_pred : numpy array of shape (n, m)
+
+
+        Returns
+        -------
+        grad : numpy array of shape (n, m)
+
+        """
+        return 0.0
+

neural_nets/tests/tests.py

@@ -122,6 +122,10 @@ def test_losses(N=50):
     time.sleep(1)
     test_WGAN_GP_loss(N)
 
+    print("Testing Cosine Loss")
+    time.sleep(1)
+    test_cosine_proximity(N)
+
 
 def test_activations(N=50):
     print("Testing Sigmoid activation")
@@ -397,6 +401,31 @@ def test_WGAN_GP_loss(N=None):
         i += 1
 
 
+def test_cosine_proximity(N=None):
+    from scipy.spatial.distance import cosine
+    from losses import Cosine
+
+    N = np.inf if N is None else N
+
+    mine = Cosine()
+    gold = cosine
+
+    i = 1
+    while i < N:
+        vector_length_max = 100
+
+        for j in range(2, vector_length_max):
+            x = np.random.uniform(0., 1., [j, ])
+            y = np.random.uniform(0., 1., [j, ])
+
+            dist = mine(x, y)
+            dist_true = gold(x, y)
+            # print(dist, dist_true - 1.)
+            assert_almost_equal(dist, dist_true)
+            print('PASSED.')
+        i += 1
+
+
 #######################################################################
 #                       Loss Function Gradients                       #
 #######################################################################
@@ -565,7 +594,6 @@ def test_softsign_activation(N=None):
         i += 1
 
 
-
 #######################################################################
 #                      Activation Gradients                           #
 #######################################################################