Questions tagged [reinforcement-learning]

Area of machine learning concerned with how software agents ought to take actions in an environment so as to maximize some notion of cumulative reward.

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Reinforcement algorithm for Trading [closed]

I am trying to implement a Reinforcement Learning Algorithm in a trading scenario. It seems natural to me to use final profit as the reward. However, in this scenario, for each trading episode, there ...
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Reinforcement Learning : Why acting greedily with the optimal value function gives you the optimal policy?

The course of David Silver about Reinforcement Learning explains how you get the optimal policy from the optimal value function. It seems to be very simple, you just have to act greedily, by ...
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Reinforcement Learning: Policy Gradient derivation question

I have been reading this excellent post: https://medium.com/@jonathan_hui/rl-policy-gradients-explained-9b13b688b146 and following the RL-videos by David Silver, and I did not get this thing: For $\...
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142 views

Hindsight Experience Replay (HER) results obtained 50 times faster than original paper?

I am reproducing the results from Hindsight Experience Replay by Andrychowicz et. al. In the original paper they present the results below, where the agent is trained for 200 epochs. 200 epochs * 800 ...
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1answer
37 views

Markov Decision Process representation

I'm attempting to model a simple process using a Markov Decision Process. Let $A$ be a set of $3$ actions : $ A \in \{b,s\}$. $T(s,a,s')$ represents the probability of if in state $s$ , take action $...
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Simulating mental disorders in machine learning systems

Is there any work as the following example in ML: Suppose a reinforcement learning system which has a fixed penalty for every ...
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1answer
44 views

How is the target_f updated in the Keras solution to the Deep Q-learning Cartpole/Gym algorithm?

There's a popular solution to the CartPole game using Keras and Deep Q-Learning: https://keon.github.io/deep-q-learning/ But there's a line of code that's confusing, this same question has been asked ...
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213 views

Q learning for blackjack, reward function?

I am currently learning reinforcement learning and am have built a blackjack game. There is an obvious reward at the end of the game (payout), however some actions do not directly lead to rewards (...
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1answer
79 views

Dynamic pricing with aggregate constraints

so I have this situation. I am trying to understand whether my customers will buy my product at a certain price based on a previous offer made to them. Specifically, I have a lot of data on my clients ...
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220 views

Deep reinforcement learning with multi-dimensional action

I am trying to design reinforcement learning algorithm. My action and state space are continuous. Action, which I would like to take can be represented by a matrix, lets say of dimension $n \times n$. ...
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Actions taken by agentn/ agent performance not improving

Hi I am trying to develop an rl agent using PPO algorithm. My agent takes an action(CFM) to maintain a state variable called RAT in between 24 to 24.5. I am using PPO algorithm of stable-baselines ...
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1answer
54 views

Assistance needed on what machine learning approach to use

👋 I'm currently writing my Master's Thesis on Subjective tagging of sounds and I feel that I've been stuck with the same problem for quite a time now and need assistance to progress. I'll, in short, ...
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55 views

Cold-start problem in Real Time Bidding

I'm currently on the reading stage of the deployment of an RTB system. I've seen the problem of a cold start (having no initial guess of how to bid) in several papers, but I haven't really seen it be ...
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1answer
155 views

Why replay memory store old states and action rather than Q-value (Deep Q-learning)

Here is the algorithm use in Google's DeepMind Atari paper The replay memory D store transition (old_state, action performed, reward, new_state) The old_state and the performed action a are needed ...
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2answers
59 views

Idenitity between TD(0) algorithm and Policy Evaluation in Dynamic Programming when alpha is equal to 1

TD(0) algorithm is defined as the iterative update of the following: $$ V(s) \leftarrow V(s) + \alpha({r + \gamma V(s')} - V(s) ) $$ Now, if we assume alpha to be equal to 1, we get the traditional ...
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132 views

Deep Q Network gives same Q values and doesn't improve

I'm trying to build a deep Q network to play snake. I've run into an issue where the agent doesn't learn and its performance at the end of the training cycle is to repeatedly kill itself. After a bit ...
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102 views

Reinforcement learning with sparse acting agent

I'm working on a problem where the optimal policy involves the agent "doing nothing" most of the time, and "doing something" during rare critical moments. Is there any literature or best practices ...
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1answer
423 views

Would Deep Q Learning work for a finite horizon problem?

I want to apply Deep Q Learning to a problem, which has a clear finite horizon definition, like: $$V(s) = \mathbb{E}[r_1 + r_2]$$ Since the horizon is finite, I do not use reward discounting. My ...
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25 views

Reinforcement Learning techniques to use if there is a direct connecction between (state, action) and reward

I want to build a model. The input state is a combination of different numbers in sequence (Their orders matter to the final result). The effectiveness of such number combination can be computed into ...
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1answer
87 views

How to improve tensorflow 2.0 code for policy gradient?

I recreated some code I found online for solving the bandits problem using policy gradient. The example was in tensorflow 1.0 so I recreated it with tensorflow 2.0 using eager execution and gradient ...
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1answer
450 views

Multiply Tensorflow sequential layer by fixed integers

I'm trying to make a simple reinforcement learning model that makes one of three decisions, A, B, or ...
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1answer
764 views

Why is orthogonal weights initialization so important for PPO?

I have implemented PPO to solve Atari environments. For the longest time I couldn't figure out why my model would not converge as fast as other open source solutions. Eventually it boiled down to this ...
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53 views

Incentivizing curiosity in a sparse reward environment

I'm quite new to reinforcement learning, but have been exploring different kinds of architectures (DQN, dueling DQN, actor critic, etc.) and evaluating their ability to solve certain problems. The ...
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1answer
106 views

Maximum Entropy Policy Gradient Derivation

I am reading through the paper on Reinforcement Learning and Control as Probabilistic Inference: Tutorial and Review by Sergey Levine. I am having a difficulty in understanding this part of the ...
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1answer
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reinforcement learning: Decompose a policy gradient

I am studying the policy gradient through the website: https://towardsdatascience.com/understanding-actor-critic-methods-931b97b6df3f Couldn't figure out how the first equation becomes the second ...
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1answer
130 views

Trouble understanding the partial differentiation used in reinforcement learning

I am studying deterministic actor-critic algorithms in reinforcement learning. I try to give a brief explanation of actor-critic algorithms before jumping into the mathematics. The actor takes in ...
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542 views

Actor-critic architecture: How is the policy updated?

I am going through the ddpg baseline code to try and gain an intuitive understanding of how the actor and critic networks function. DDPG has two components: the actor which is the deterministic ...
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559 views

reinforcement learning: PPO vs. DDPG vs. TRPO - difference and intuition

I know there is a lot of blog talk about the PPO, DDPG and TRPO, but I am wondering would it be possible to explain the differences of these methods in layman's term? What's the intuition behind them ...
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Rewards are converged but with a lot of variations

I am training a reinforcement learning agent on an episodic task of fixed episode length. I am tracking the training process by plotting the cumulative rewards over an episode. I am using tensorboard ...
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Deep Q Learning - training slows down significantly

I'm trying to build a deep Q network to play snake. I designed the game so that the window is 600 by 600 and the snake's head moves 30 pixels each tick. I implemented the DQN algorithm with memory ...
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Autonomous learning - chatbots

My chatbots need to be trained when we get new data or feedbacks from users. Can someone provides ways how these chatbots can learn on themselves and become intelligent day by day? Some of techniques ...
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111 views

Reinforcement Learning in NLP for chatbots

Is anyone aware of any successful implementation of reinforcement learning for NLP. I am looking to for chatbots which can learn automatically. Tried searching internet but found very few articles ...
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118 views

Having a reward structure which gives high positive rewards compared to the negative rewards

I am training an RL agent using PPO algorithm for a control problem. The objective of the agent is to maintain temperature in a room. It is an episodic task with episode length of 9 hrs and step size(...
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35 views

DNN loss gets smaller but accuracy stays the same

I am learning a DeepNN to choose between three decisions in a simulation. Therefore, I can run the simulation as often as I want and can generate as many samples as I want. Based on this tutorial (...
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1answer
49 views

Formulation of a reward structure

I am new to reinforcement learning and experimenting with training of RL agents. I have a doubt about reward formulation, from a given state if a agent takes a good action i give a positive reward, ...
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241 views

Actor Critic Model implementation

I am going to work on a project which requires implementation of A2C model using Tensorflow 2.0. I am new in the Machine Learning field and also in Python. These are topics which I have covered ...
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1answer
1k views

Training a model that has both 2D and 1D features using a CNN

I'm looking to pre-train a model for an RL agent but I'm having some trouble figuring some stuff out. Dataset: Minerl MineRLNavigateDense-v0 The observation space includes : 2D screen input (64,64) ...
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1answer
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How to handle differences between training and deploying of an RL agent

Hi I am training an RL agent for a control problem. The objective of the agent is to maintain temperature in a zone. It is an episodic task with episode length of 10 hrs and actions being taken every ...
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42 views

How can I increase the speed and performance of my implementation of an AI for Reversi?

I made an AI for Reversi, aka Othello (8×8), like Alpha Zero, using this book. This book is written in Japanese. The source code of the AI I implemented can be found in this Github repository. There ...
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357 views

DQN vs PG - when to use which?

I'd like to understand when using PG methods is more adequate than using DQN methods. Just to give a bit of background: I am currently using both APEX and R2D2 for my projects. Both work very well in ...
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1answer
457 views

Different results every time I train a reinforcement learning agent

I am training an RL agent for a control problem using PPO algorithm. I am using stable-baselines library for it. The objective of an agent is to maintain a temperature of 24 deg in a zone and it ...
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1answer
3k views

Evaluating a trained Reinforcement Learning Agent?

I am new to reinforcement learning agent training. I have read about PPO algorithm and used stable baselines library to train an agent using PPO. So my question here is how do I evaluate a trained RL ...
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118 views

Transitioning from Math PhD to ML research [closed]

I am currently a Math PhD about to defend in January. I work in a field in functional analysis that uses a lot of measure theory (but no stats). I have been considering transitioning careers since I ...
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2answers
156 views

Deep Q network disregards input, giving identical output no matter the input state

I've creating a very simple game, The board is an array of size 6. 0 is "empty cell" , 5 is "Goal", 8 is "player location" [8 0 0 5 0 0] for example means the agent needs to move 2 "right" to win. ...
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1answer
1k views

What are regret bounds?

I searched for the term and it appears in a few articles but it is used without explanation. The only explanation I could find is in a PhD thesis: "Regret bounds are the common thread in the analysis ...
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1answer
195 views

transform a supervised neural network to reinforcement learning?

I have a functional LSTM model that works with an acceptable performance. How can I now convert this supervised model to a reinforcement learning model for improving the performane? Is there any ...
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1answer
2k views

Policy Gradient with continuous action space

How to apply reinforce/policy-gradient algorithms for continuous action space. I have learnt that one of the advantages of policy gradients is , it is applicable for continuous action space. One way I ...
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1answer
432 views

Deep reinforcement learning on changing data sizes

I have a game that I want to build a model that will learn to play the game. Yet, the environment output is two lists that represent the location and number of soldiers of the user and Opponent. The ...
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Agent always takes a same action in DQN - Reinforcement Learning

I have trained an RL agent using DQN algorithm. After 20000 episodes my rewards are converged. Now when I test this agent, the agent is always taking the same action , irrespective of state. I find ...
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69 views

Policy Gradient custom loss function not working

I was experimenting with my policy gradient reinforcement learning algorithm, and I was wondering if I could use a similar method to the supervised cross-entropy. So, instead of using existing labels, ...

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