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/*var $data = [{"src":["<bos>", "das", "ist", "ein", "kleines", "haus", "<eos>"],
"tgt":["<bos>", "this", "is", "a", "small", "house", "<eos>"]}
];*/
var $data = [{"src":["<bos>", "das", "<eos>"],
"tgt":["<bos>", "this", "<eos>"]}];//,
/* {"src":["<bos>", "mein", "<eos>"],
"tgt":["<bos>", "my", "<eos>"]}];*/
var make_vocab = function (data)
{
var k = 0;
var vocab = {}, ivocab = [];
for (var i=0; i<data.length; i++) {
for (var j=0; j<data[i].length; j++) {
var w = data[i][j];
if (vocab[w]==undefined) {
vocab[w] = k;
ivocab[k] = w;
k++;
}
}
}
return [vocab,ivocab,ivocab.length];
}
var $vocab_src, $ivocab_src,$vocab_sz_src;
var $vocab_tgt, $ivocab_tgt,$vocab_sz_tgt;
[$vocab_src,$ivocab_src,$vocab_sz_src] = make_vocab($data.map(function(i){return i["src"]}));
$vocab_sz_src++;
[$vocab_tgt,$ivocab_tgt,$vocab_sz_tgt] = make_vocab($data.map(function(i){return i["tgt"]}));
var one_hot = function (n, i)
{
var m = new R.Mat(n,1);
m.set(i, 0, 1);
return m;
}
var stopping_criterion = function (c, d, iter, margin=0.01, max_iter=100)
{
if (Math.abs(c-d) < margin || iter>=max_iter)
return true;
return false;
}
var cat = function (a, b)
{
R.assert(a.d==1 && b.d==1);
var m = new R.Mat(a.n+b.n, 1);
var i;
for (i=0; i<a.n; i++) {
m.w[i] = a.w[i];
m.dw[i] = a.dw[i];
}
for (var j=0; j<b.n; j++) {
m.w[i+j] = b.w[j];
m.dw[i+j] = b.dw[j];
}
return m;
}
function shuffle(array) {
var currentIndex = array.length, temporaryValue, randomIndex;
// While there remain elements to shuffle...
while (0 !== currentIndex) {
// Pick a remaining element...
randomIndex = Math.floor(Math.random() * currentIndex);
currentIndex -= 1;
// And swap it with the current element.
temporaryValue = array[currentIndex];
array[currentIndex] = array[randomIndex];
array[randomIndex] = temporaryValue;
}
return array;
}
var hidden_sizes = [5];
var encoder = R.initRNN($vocab_sz_src, hidden_sizes, $vocab_sz_src+100);
encoder["name"] = "encoder";
var decoder = R.initRNN($vocab_sz_src+100+$vocab_sz_tgt, hidden_sizes, $vocab_sz_tgt);
decoder["name"] = "decoder";
var solver = new R.Solver();
var h = {};
var inp = null;
costs = [];
var epoch = 0;
decoder["encoder_Wxh0"] = encoder["Wxh0"];
decoder["encoder_Whh0"] = encoder["Whh0"];
decoder["encoder_bhh0"] = encoder["bhh0"];
decoder["encoder_Whd"] = encoder["Whd"];
decoder["encoder_bd"] = encoder["bd"];
var x = encoder.Whh0.w[0]
var y = decoder.Whh0.w[0]
var enc_hs = [];
var dec_hs = [];
var dec_inps = [];
while (true)
{
$data = shuffle($data);
var c = 0.0;
for (var i=0; i<$data.length; i++) {
var last_enc_h;
var G = new R.Graph();
for (var j=0; j<$data[i]["src"].length; j++) {
var src = $data[i]["src"][j];
var inp = one_hot($vocab_sz_src, $vocab_src[src]);
var h = R.forwardRNN(G, encoder, hidden_sizes, inp, h);
last_enc_h = h;
enc_hs.push(h);
}
for (var z=0; z<G.backprop.length; z++) {
G.backprop[z]["mark"] = "encoder";
}
var context = last_enc_h.o;
var h = {}
for (var k=0; k<$data[i]["tgt"].length; k++) {
var src = $data[i]["tgt"][k],
tgt = $data[i]["tgt"][k+1];
inp = cat(one_hot($vocab_sz_tgt, $vocab_tgt[src]), context);
dec_inps.push(inp);
h = R.forwardRNN(G, decoder, hidden_sizes, inp, h);
dec_hs.push(h);
var logprobs = h.o;
var probs = R.softmax(logprobs);
var target = $vocab_tgt[tgt];
cost = -Math.log(probs.w[target]);
if (!cost || cost==Infinity) cost = 0; // hmmm
logprobs.dw = probs.w;
logprobs.dw[target] -= 1;
c += cost;
// update weights
G.backward();
// copy grads? decoder.Wxh0 -> encoder.Whd ?
for (var z=0; z<last_enc_h.o.dw.length; z++) {
last_enc_h.o.dw[z] = dec_inps[0].dw[z];
}
G.backward1();
//exit();
solver.step(decoder, 0.01, 0.000001, 5.0);
}
}
epoch++;
costs.push(c);
if (stopping_criterion(costs[costs.length-2], cost, epoch))
break;
}
var k = 10;
var samples = [];
for (var q=0; q < k; q++) {
//var x = ["<bos>", "das", "ist", "ein", "kleines", "haus", "<eos>"];
var x = ["<bos>", "das", "<eos>"];
var _, cntxt;
var o = {};
var G = new R.Graph(false);
for (var i=0; i<x.length; i++) {
var src = x[i];
var inp = one_hot($vocab_sz_src, $vocab_src[src]);
var h = R.forwardRNN(G, encoder, hidden_sizes, inp, h);
}
cntxt = h.o;
var w = "<bos>", lh;
var prev = {};
var str = "";
var z = 0;
var p = 1;
while (true) {
var inp = cat(one_hot($vocab_sz_tgt, $vocab_tgt[w]), cntxt);
var lh = R.forwardRNN(G, decoder, hidden_sizes, inp, prev);
prev = lh;
var logprobs = lh.o;
var probs = R.softmax(logprobs);
var x = R.samplei(probs.w);
p *= probs.w[x];
src = $ivocab_tgt[x];
str += " "+src;
z++;
if (src == "<eos>" || z==100)
break;
}
samples.push( {"transl":str, "score":p } );
}
best = "";
best_score = -999999;
for (var q = 0; q<samples.length; q++) {
if (best_score < samples[q].score) {
best = samples[q].transl
}
}
alert(best);
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