Please see Yann LeCun's page for the original MNIST dataset.
torch-rocks install https://raw.github.com/andresy/mnist/master/rocks/mnist-scm-1.rockspec
local mnist = require 'mnist'
local trainset = mnist.traindataset()
local testset = mnist.testdataset()
print(trainset.size) -- to retrieve the size
print(testset.size) -- to retrieve the size
Then, the i-th example is retrieved with:
local ex = trainset[i]
local x = ex.x -- the input (a 28x28 ByteTensor)
local y = ex.y -- the label (0--9)