From 4cdeae32836f002c20bd3e93543a22b45e198300 Mon Sep 17 00:00:00 2001
From: Adam Paszke <adam.paszke@gmail.com>
Date: Sat, 24 Sep 2016 10:36:11 -0700
Subject: [PATCH] Return only unique variables from parameters()

---
 test/test_nn.py               | 15 +++++++++++++++
 torch/__init__.py             | 18 ++++++++++++++----
 torch/nn/modules/container.py | 27 +++++++++++++++++----------
 torch/nn/modules/module.py    | 12 +++++++++---
 4 files changed, 55 insertions(+), 17 deletions(-)

diff --git a/test/test_nn.py b/test/test_nn.py
index 2d430beb161..75e346ddc91 100644
--- a/test/test_nn.py
+++ b/test/test_nn.py
@@ -203,6 +203,21 @@ class TestNN(NNTestCase):
         module.__repr__()
         str(module)
 
+    def test_parameters(self):
+        def num_params(module):
+            return len(list(module.parameters()))
+        class Net(nn.Container):
+            def __init__(self):
+                super(Net, self).__init__(
+                    l1=l,
+                    l2=l
+                )
+        l = nn.Linear(10, 20)
+        n = Net()
+        s = nn.Sequential(l, l, l, l)
+        self.assertEqual(num_params(l), 2)
+        self.assertEqual(num_params(n), 2)
+        self.assertEqual(num_params(s), 2)
 
     def test_Dropout(self):
         input = torch.Tensor(1000)
diff --git a/torch/__init__.py b/torch/__init__.py
index 81be2887e69..a14d5eb2b3a 100644
--- a/torch/__init__.py
+++ b/torch/__init__.py
@@ -24,10 +24,20 @@ del old_flags
 ################################################################################
 
 def typename(o):
-    module = o.__module__ + '.'
-    if module == '__builtin__.':
-        module = ''
-    return module + o.__class__.__name__
+    module = ''
+    class_name = ''
+    if hasattr(o, '__module__') and o.__module__ != 'builtins' \
+            and o.__module__ != '__builtin__' and o.__module__ is not None:
+        module = o.__module__ + '.'
+
+    if hasattr(o, '__qualname__'):
+        class_name = o.__qualname__
+    elif hasattr(o, '__name__'):
+        class_name = o.__name__
+    else:
+        class_name = o.__class__.__name__
+
+    return module + class_name
 
 
 def is_tensor(obj):
diff --git a/torch/nn/modules/container.py b/torch/nn/modules/container.py
index f30267abf3d..dd34b8ada34 100644
--- a/torch/nn/modules/container.py
+++ b/torch/nn/modules/container.py
@@ -1,15 +1,17 @@
+from collections import OrderedDict
+
+import torch
 from torch.autograd import Variable
 from .module import Module
-from collections import OrderedDict
 
 
 class Container(Module):
     """This is the base container class for all neural networks you would define.
     You will subclass your container from this class.
-    In the constructor you define the modules that you would want to use, 
-    and in the __call__ function you use the constructed modules in 
+    In the constructor you define the modules that you would want to use,
+    and in the __call__ function you use the constructed modules in
     your operations.
-    
+
     To make it easier to understand, given is a small example.
     ```
     # Example of using Container
@@ -23,16 +25,16 @@ class Container(Module):
             output = self.relu(self.conv1(x))
             return output
      model = Net()
-     ```     
-    
+     ```
+
     One can also add new modules to a container after construction.
     You can do this with the add_module function.
 
     ```
     # one can add modules to the container after construction
-    model.add_module('pool1', nn.MaxPool2d(2, 2)
+    model.add_module('pool1', nn.MaxPool2d(2, 2))
     ```
-    
+
     The container has one additional method `parameters()` which
     returns the list of learnable parameters in the container instance.
     """
@@ -45,13 +47,18 @@ class Container(Module):
     def add_module(self, name, module):
         if hasattr(self, name):
             raise KeyError("attribute already exists '{}'".format(name))
+        if not isinstance(module, Module):
+            raise ValueError("{} is not a Module subclass".format(
+                torch.typename(module)))
         setattr(self, name, module)
         if module is not None:
             self.modules.append(module)
 
-    def parameters(self):
+    def parameters(self, memo=None):
+        if memo is None:
+            memo = set()
         for module in self.modules:
-            for p in module.parameters():
+            for p in module.parameters(memo):
                 yield p
 
 
diff --git a/torch/nn/modules/module.py b/torch/nn/modules/module.py
index 56f5ae45abb..69a74dc3f6c 100644
--- a/torch/nn/modules/module.py
+++ b/torch/nn/modules/module.py
@@ -75,10 +75,16 @@ class Module(object):
             fn.register_hook(key, lambda gi,go,hook=hook: hook(self, gi, go))
         return result
 
-    def parameters(self):
-        if hasattr(self, 'weight') and self.weight is not None:
+    def parameters(self, memo=None):
+        if memo is None:
+            memo = set()
+        if hasattr(self, 'weight') and self.weight is not None \
+                and self.weight not in memo:
+            memo.add(self.weight)
             yield self.weight
-        if hasattr(self, 'bias') and self.bias is not None:
+        if hasattr(self, 'bias') and self.bias is not None \
+                and self.bias not in memo:
+            memo.add(self.bias)
             yield self.bias
 
     def zero_grad(self):