Then you will never able to realise that option 3 is better than option 1.
Strike a Balance between Exploring and ExploitingLearning to make these choices is part of reinforcement learning.
This means that sometimes you purposely have to decide not to choose the action that you think will be the most rewarding in order to gain new information, but sometimes ended up making some bad decisions in the process of exploration.
But at the same time, you want to maximise your reward, by exploiting what you know worked best.
So how do we strike a balance between sufficiently exploring the unknowns and exploiting the optimal action?sufficient initial exploration such that the best options may be identifiedexploit the optimal option in order to maximise the total rewardcontinuing to set aside a small probability to experiment with sub-optimal and unexplored options, in case they provide better returns in the futureif those experiment options turn out to be doing well, the algorithm must update and begin selecting this optionEpsilon GreedyIn reinforcement learning, we can decide how much exploration to be done.
This is the epsilon-greedy parameter which ranges from 0 to 1, it is the probability of exploration, typically between 5 to 10%.
If we set 0.
1 epsilon-greedy, the algorithm will explore random alternatives 10% of the time and exploit the best options 90% of the time.
Evaluate Different Epsilon GreedyI’ve created a tic-tac-toe game where agents can learn the game by playing against each other.
First, let me introduce you to our agents, they are agent X and agent O.
Agent X always goes first and actually has the advantage to win more often than agent O.
In order to figure out the most suitable epsilon-greedy value for each agent for this game, I will test different epsilon-greedy value.
First, initialise agent X with epsilon-greedy of 0.
01, means there is 1% probability agent X will choose to explore instead of exploiting.
Then, agents will play against each other for 10,000 games, and I will record the number of times agent X wins.
After 10,000 games, I will increase the epsilon-greedy value to 0.
02 and agents will play another 10,000 games.
Agent X (eps increment) vs Agent O (eps 0.
05), the results are as follows:Number of games (out of 10,000) won by agent X on different epsilon-greedy valueThe blue line is the number of times agent X won against agent O.
The winning rate decreases as the epsilon-greedy value increases and peaked at winning 9268 games at the epsilon-greedy value of 0.
05 (agent X explores 5% of the time).
Agent O begin to win more games as agent X explores more than 50% of the time.
Let us try something, agent O challenging agent X with an optimal 5% epsilon greedy, let’s see how agent O performs on different epsilon-greedy value.
Number of games won by agent O on different epsilon-greedy valueGiven agent X has optimal epsilon greedy and advantage to start first in the game, agent O lost most of the games before it is able to learn the game.
Let’s tweak epsilon greedy of agent X to 100%, where agent X will be playing random actions all the time.
Number of games won by agent O on different epsilon-greedy value, where agent X play randomlyAgent O is able to learn the game and win against agent X, peaking at 4% epsilon greedy and begin losing at 30%.
LastlyExplore the online demo and challenge our agent in a game of tic-tac-toe.
Just want to end with this picture.