Implemented offset.

theano/tensor/basic.py

@@ -6557,14 +6557,16 @@ class AllocDiag(Op):
 
         axis1 = np.minimum(self.axis1, self.axis2)
         axis2 = np.maximum(self.axis1, self.axis2)
+        offset = self.offset
 
         # Create array with one extra dimension for resulting matrix
-        result_shape = x.shape[:-1] + (x.shape[-1],) * 2
+        result_shape = x.shape[:-1] + (x.shape[-1] + offset,) * 2
         result = np.zeros(result_shape, dtype=x.dtype)
 
         # Create slice for diagonal in final 2 axes
-        diagonal_slice = ((len(result_shape) - 2) * [slice(None)] +
-                          [np.arange(x.shape[-1])] * 2)
+        diagonal_slice = ((len(result_shape) - 2)  * [slice(None)] +
+                          [np.arange(x.shape[-1]) + max(0, -offset),
+                           np.arange(x.shape[-1]) + max(0, offset)])
 
         # Fill in final 2 axes with x
         result[diagonal_slice] = x