Public
Edited
May 20, 2018
1 star
function Qestimate(action, history) {
let action_history = history.filter((s) => s.action == action);
let total_reward = action_history.reduce((acc,s) => s.reward + acc , 0);
if(action_history.length == 0) return 0;
return total_reward / action_history.length;
}
function greedy(history) {
return actions.reduce( (best, action) => {
let reward = Qestimate(action, history);
if(!reward) return best;
if( reward < best.reward) return best;
else return { action:action, reward:reward };
}, {action:4, reward:0}).action;
}
true_values = () => range(10).map((v) => normal())
function simple_bandit(true_values, epsilon) {
var Q = new Array(true_values.length).fill(0);
var N = new Array(true_values.length).fill(0);
let choices = d3.range(true_values.length);
let random_choice = (arr) => arr[Math.floor(Math.random()*arr.length)];
let strategy = () => {
// Random (exploratory) selection
let choice = random_choice(choices);
if(Math.random() > epsilon) {
// Greedy choice
let qs = Q.map((q,a) => {return {choice:a, q:q}});
qs.sort((a,b) => (a.q < b.q));
choice = random_choice(qs.filter((a) => a == qs[0])).choice;
}
let reward = bandit_reward(true_values,choice);
N[choice] += 1;
Q[choice] += (reward - Q[choice]) / N[choice];
return {choice: choice, reward: reward};
}
return strategy;
}
Purpose-built for displays of data
Observable is your go-to platform for exploring data and creating expressive data visualizations. Use reactive JavaScript notebooks for prototyping and a collaborative canvas for visual data exploration and dashboard creation.
