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/** * **[Gaussian error function](http://en.wikipedia.org/wiki/Error_function)** * * The `errorFunction(x/(sd * Math.sqrt(2)))` is the probability that a value in a * normal distribution with standard deviation sd is within x of the mean. * * This function returns a numerical approximation to the exact value. * It uses Horner's method to evaluate the polynomial of τ (tau). * * @param {number} x input * @return {number} error estimation * @example * errorFunction(1).toFixed(2); // => '0.84' */function errorFunction(x) {    const t = 1 / (1 + 0.5 * Math.abs(x));    const tau =        t *        Math.exp(            -x * x +                ((((((((0.17087277 * t - 0.82215223) * t + 1.48851587) * t -                    1.13520398) *                    t +                    0.27886807) *                    t -                    0.18628806) *                    t +                    0.09678418) *                    t +                    0.37409196) *                    t +                    1.00002368) *                    t -                1.26551223        );    if (x >= 0) {        return 1 - tau;    } else {        return tau - 1;    }}
export default errorFunction;