Remove edge direction for saved_tensors (#63)

Fixes #61

Author: Varal7

torchviz/dot.py

@@ -139,7 +139,7 @@ def add_nodes(fn):
         if hasattr(fn, 'saved_tensors'):
             for t in fn.saved_tensors:
                 seen.add(t)
-                dot.edge(str(id(t)), str(id(fn)))
+                dot.edge(str(id(t)), str(id(fn)), dir="none")
                 dot.node(str(id(t)), get_var_name(t), fillcolor='orange')