Merge pull request #12 from trigeorgis/master

Speedup: Use tensordot instead of einsum
menpo · Dec 8, 2014 · 5b6c0cd · 5b6c0cd
2 parents 6154f9f + 449611f
commit 5b6c0cd
Showing 1 changed file with 7 additions and 1 deletion.
diff --git a/menpofit/transform/modeldriven.py b/menpofit/transform/modeldriven.py
@@ -262,7 +262,13 @@ def d_dp(self, points):
 
         # dW_dl:  n_points x (n_dims) x n_centres x n_dims
         # dX_dp:  (n_points x n_dims) x n_params
-        dW_dp = np.einsum('ild, lpd -> ipd', self.dW_dl, dX_dp)
+
+
+        # The following is equivalent to
+        # np.einsum('ild, lpd -> ipd', self.dW_dl, dX_dp)
+        dW_dp = np.tensordot(self.dW_dl, dX_dp, (1, 0))
+        dW_dp = dW_dp.diagonal(axis1=3, axis2=1)
+
         # dW_dp:  n_points x n_params x n_dims
 
         return dW_dp