recycle/forget offset unused

[achalddave]

nn.Recurrent passes an offset variable to :recycle and :forget, which doesn't seem to be used anywhere. Am I missing something, or is the offset parameter unused?

Call to :recycle:

rnn/Recurrent.lua

Line 132 in ef98a97

function Recurrent:recycle()

Call to :forget:

rnn/Recurrent.lua

Line 136 in ef98a97

function Recurrent:forget()

Defn of :recycle:

rnn/AbstractRecurrent.lua

Line 80 in ef98a97

function AbstractRecurrent:recycle(offset)

Defn of :forget:

rnn/AbstractRecurrent.lua

Line 113 in ef98a97

function AbstractRecurrent:forget()

[achalddave]

This causes the Recurrent class to store an extra copy of the RecurrentModule, which can be extremely expensive if the module requires significant memory:

require 'rnn'
local _ = require 'moses'

local model = nn.Recurrent(nn.MulConstant(2), nn.MulConstant(3))
print('#sharedClones after init:', _.count(model.sharedClones))

local input = torch.rand(1)
model:forward(input)
model:forward(input)
print('#sharedClones after forward:', _.count(model.sharedClones)) -- 1

model:forget()
print('#sharedClones after forget:', _.count(model.sharedClones)) -- 1
model:forward(input)
model:forward(input)
print('#sharedClones after 2nd forward:', _.count(model.sharedClones)) -- 2