def pooling(X):
        pool = nn.MaxPool2d(2, 2, return_indices=True)
        unpool = nn.MaxUnpool2d(2, 2)
        all_indices = []
        all_outputs = []

        # Encoder
        self.all_outputs.append(X.shape)

        X, indices = pool(X)
        self.all_indices.append(indices)
        self.all_outputs.append(X.shape)

        X, indices = pool(X)
        self.all_indices.append(indices)
        self.all_outputs.append(X.shape)

        X, indices = pool(X)
        self.all_indices.append(indices)
        self.all_outputs.append(X.shape)

        X, indices = pool(X)
        self.all_indices.append(indices)
        #self.all_outputs.append(X.shape)

        # Decoder
        X = self.unpool(X, self.all_indices[-1], output_size=self.all_outputs[-1])
        X = self.unpool(X, self.all_indices[-2], output_size=self.all_outputs[-2])
        X = self.unpool(X, self.all_indices[-3], output_size=self.all_outputs[-3])
        X = self.unpool(X, self.all_indices[-4], output_size=self.all_outputs[-4])