Problem using adamax under lua5.2

Hello,

I run into some problems using adamax

/home/XXXX/torch/install/share/lua/5.2/optim/adamax.lua:48: attempt to call global 'unpack' (a nil value)
stack traceback:
    /home/XXXX/torch/install/share/lua/5.2/optim/adamax.lua:48: in function 'adamax'

I installed torch under lua5.2 instead of luaJIT and it seems that, in lua5.2 the function 'unpack' was replaced by 'table.unpack'

See : https://stackoverflow.com/questions/25794364/lua-trouble-attempt-to-call-global-unpack-a-nil-value

EDIT (Sample code)

require 'nn'
require 'optim'

model = nn.Sequential() 
inputs = 2; outputs = 1
model:add(nn.Linear(inputs, outputs))

criterion = nn.MSECriterion()

params, gradParams = model:getParameters()
config = {learningRate = 1e-3,momentum = 0.5}

function feval(params)
   gradParams:zero()
   local outputs = model:forward(torch.ones(2))
   local loss = criterion:forward(outputs, torch.zeros(1))
   local dloss_doutputs = criterion:backward(outputs, torch.zeros(1))
   model:backward(torch.ones(2), dloss_doutputs)
   return loss, gradParams
end

optim.adamax(feval, params, optimState)

/home/XXXX/torch/install/bin/lua: /home/XXXX/torch/install/share/lua/5.2/optim/adamax.lua:48: attempt to call global 'unpack' (a nil value)
stack traceback:
    /home/XXXX/torch/install/share/lua/5.2/optim/adamax.lua:48: in function 'adamax'
    ex_fail.lua:22: in main chunk
    [C]: in function 'dofile'
    ...urin/torch/install/lib/luarocks/rocks/trepl/scm-1/bin/th:150: in main chunk
    [C]: in ?

torch / optim

Problem using adamax under lua5.2 #160