Function sign

tuna.js:202–208

(x)

}

function sign(x) {
    if (x === 0) {
        return 1;
    } else {
        return Math.abs(x) / x;
    }
}

function tanh(n) {
    return (Math.exp(n) - Math.exp(-n)) / (Math.exp(n) + Math.exp(-n));