al-ilm-nn-julia-flux-7.jl

using Images
using MLDatasets
using Flux: ADAM,
            argmax, 
            Chain, 
            crossentropy, 
            Dense, 
            params,
            relu, 
            softmax, 
            throttle,
            train!

const N = 2000
const EPOCHS = 30

x_train, y_train_coarse, y_train_fine = CIFAR100.traindata();

x_vec = [float.(reshape(x_train[:, :, :, i], :)) for i in 1:N];
X = hcat(x_vec...);            
Y = onehotbatch(y_train_fine[1:N], 0:99);

model = Chain(
    Dense(32^2 * 3, 32 * 10, relu),
    Dense(32 * 10, 100),
    softmax
);

loss(x, y) = crossentropy(model(x), y);
accuracy(x, y) = mean(argmax(model(x)) .== argmax(y));

dataset = Base.Iterators.repeated((X, Y), EPOCHS);
evalcb = () -> @show(loss(X, Y));

opt = SGD(params(model));
train!(loss, dataset, opt, cb = throttle(evalcb, 10));
accuracy(X, Y)