Ngram creation with probabilities
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function n_grams(tokens,n = 2,sep = ' ',epoch = 3) { | |
var ngrams = []; | |
for (let j=0; j < epoch; j++) { | |
//remove first token | |
if (j!=0){tokens.shift();} | |
for (var i = 0; i < tokens.length -n; i+=n) { | |
let ng1 = tokens.slice(i, i+n).join(sep); | |
let ng2 = tokens.slice(i+n, i+n+n).join(sep); | |
let ngram = [ng1.replace(/\s?(START|END)\s?/gm,'')/*.trim()*/, ng2.replace(/\s?(START|END)\s?/gm,'')/*.trim()*/]; | |
// /!\ pas de trim() à cause des tokens sur chars | |
// console.log(`${i} : ${tokens[i]}`); | |
if (tokens[i] === 'START') { | |
ngrams.push(["START", ng1.replace(/(START|END)\s?/g, '')]); | |
ngrams.push([ng1.replace(/(START|END)\s?/g, ''),ng2]); | |
} else if (tokens[i+n] === 'START') { // i+n+n est donc START | |
ngrams.push([ng1, "END"]); | |
//ngrams.push(["START", ng1.replace(/START\s?/g, '')]); | |
} else if (i === tokens.length) { | |
ngrams.push([ng1, "END"]); | |
} else { | |
// console.log(`On peut pusher i: ${i} / Token: ${tokens[i]} / Ngram: ${ngram}`); | |
ngrams.push(ngram); | |
} | |
} | |
console.log(`================================= Epoch ${j} : ${ngrams.length} ngrams`); | |
} | |
ngrams = [ | |
// count the number of times each ngram occurs | |
...ngrams | |
.map(JSON.stringify) | |
.reduce((acc, v) => acc.set(v, (acc.get(v) || 0) + 1), new Map()) | |
.entries(), | |
].map(([k, v]) => JSON.parse(k).concat(v)).sort(function (a, b) { | |
return b[2] - a[2]; | |
}); | |
//groups | |
let groups = ngrams.reduce((acc, cur) => { | |
if (!acc[cur[0]]) { | |
acc[cur[0]] = []; | |
} | |
acc[cur[0]].push([cur[1],cur[2]]); | |
return acc; | |
}, {}); | |
// console.log('Groups: ',groups); | |
//set probabilities | |
Object.entries(groups).forEach(entry => { | |
const [key, value] = entry; | |
//get sum and probabilities | |
const sum = value.reduce((acc, cur) => acc + cur[1], 0); | |
const probabilities = value.map(x => [x[0], x[1] / sum]); | |
groups[key] = probabilities; | |
}); | |
//console.log('Groups: ',groups); | |
return groups; //Object.entries(groups); | |
} |
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