'Forward propagate the inputs of a convolutional network layer to
produce output.
Arguments:
layer: the conv layer as a parameter object
I (Tensor): inputs
F (Tensor): the weights (filters)
O (Tensor): outputs
alpha (float, optional): linear scaling.  Defaults to 1.0
relu (bool, optional): apply ReLu before output.  Default not to.
repeat (int, optional): Repeat this operation the specified number
of times.  Defaults to 1.'

@abc.abstractmethod
def fprop_conv(self, layer, I, F, O, alpha=1.0, relu=False, repeat=1):

    raise NotImplementedError()
