allow encoder to cross attend

Author: lucidrains

setup.py

@@ -3,7 +3,7 @@
 setup(
   name = 'x-transformers',
   packages = find_packages(exclude=['examples']),
-  version = '0.3.1',
+  version = '0.3.2',
   license='MIT',
   description = 'X-Transformers - Pytorch',
   author = 'Phil Wang',

x_transformers/x_transformers.py

@@ -343,7 +343,6 @@ def forward(self, x, context = None, mask = None, context_mask = None):
 class Encoder(AttentionLayers):
     def __init__(self, **kwargs):
         assert 'causal' not in kwargs, 'cannot set causality on encoder'
-        assert 'cross_attend' not in kwargs, 'encoder cannot cross attend'
         super().__init__(causal = False, **kwargs)
 
 class Decoder(AttentionLayers):