lib/gaussian.js
function(x) {
    var z = Math.abs(x);
    var t = 1 / (1 + z / 2);
    var r = t * Math.exp(-z * z - 1.26551223 + t * (1.00002368 +
            t * (0.37409196 + t * (0.09678418 + t * (-0.18628806 +
            t * (0.27886807 + t * (-1.13520398 + t * (1.48851587 +
            t * (-0.82215223 + t * 0.17087277)))))))))
    return x >= 0 ? r : 2 - r;
  }
function(x) {
    var z = Math.abs(x);
    var t = 1 / (1 + z / 2);
    var r = t * Math.exp(-z * z - 1.26551223 + t * (1.00002368 +
            t * (0.37409196 + t * (0.09678418 + t * (-0.18628806 +
            t * (0.27886807 + t * (-1.13520398 + t * (1.48851587 +
            t * (-0.82215223 + t * 0.17087277)))))))))
    return x >= 0 ? r : 2 - r;
  }
function ( x ) { var z = Math . abs ( x ) ; var t = 1 / ( 1 + z / 2 ) ; var r = t * Math . exp ( - z * z - 1.26551223 + t * ( 1.00002368 + t * ( 0.37409196 + t * ( 0.09678418 + t * ( - 0.18628806 + t * ( 0.27886807 + t * ( - 1.13520398 + t * ( 1.48851587 + t * ( - 0.82215223 + t * 0.17087277 ) ) ) ) ) ) ) ) ) return x >= 0 ? r : 2 - r ; }
Complementary error function From Numerical Recipes in C 2e p221
Complementary error function From Numerical Recipes in C 2e p221