gradient ascent in webppl

gradient-ascent.js

var f = function(theta) {
  //return 30 * Math.log(theta) + 20 * Math.log(1-theta)
  return Binomial({p: theta, n: 30}).score(14)
}


globalStore["x"] = 0.001;
repeat(100,
       function() {
         var x = globalStore["x"],
             xL = ad.lift(x);

         var yL = f(xL);
         yL.backprop();
         var dxL = ad.derivative(xL);
         console.log(x, ad.value(yL), dxL);

         var newX = (dxL > 0 ? x + 0.01 : x - 0.01);

         globalStore["x"] = newX;
       })