A sequential container. Modules will be added to it in the order they are passed in the constructor. Alternatively, an
OrderedDictof modules can be passed in. The
Sequentialaccepts any input and forwards it to the first module it contains. It then “chains” outputs to inputs sequentially for each subsequent module, finally returning the output of the last module.
The value a
Sequentialprovides over manually calling a sequence of modules is that it allows treating the whole container as a single module, such that performing a transformation on the
Sequentialapplies to each of the modules it stores (which are each a registered submodule of the
What’s the difference between a
ModuleListis exactly what it sounds like–a list for storing
Modules! On the other hand, the layers in a
Sequentialare connected in a cascading way.
# Using Sequential to create a small model. When `model` is run, # input will first be passed to `Conv2d(1,20,5)`. The output of # `Conv2d(1,20,5)` will be used as the input to the first # `ReLU`; the output of the first `ReLU` will become the input # for `Conv2d(20,64,5)`. Finally, the output of # `Conv2d(20,64,5)` will be used as input to the second `ReLU` model = nn.Sequential( nn.Conv2d(1,20,5), nn.ReLU(), nn.Conv2d(20,64,5), nn.ReLU() ) # Using Sequential with OrderedDict. This is functionally the # same as the above code model = nn.Sequential(OrderedDict([ ('conv1', nn.Conv2d(1,20,5)), ('relu1', nn.ReLU()), ('conv2', nn.Conv2d(20,64,5)), ('relu2', nn.ReLU()) ]))