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Showing posts with label Tuning. Show all posts
Showing posts with label Tuning. Show all posts

Tuesday, April 20, 2021

MBRL Tuning for Partially Understood Environments

Below is very technical,  but I do like some of the background statements such as 'solving tasks in a partially understood environment ...'.    And the idea of optimizing agents to resolve elements of understanding.  (Which exemplifies the situations we are often in).    So I am not saying I understand this yet, but working through it now for broader application.  As part of my broader study of practical reinforcement learning.

The Importance of Hyperparameter Optimization for Model-based Reinforcement Learning

Nathan Lambert, Baohe Zhang, Raghu Rajan, AndrĂ© Biedenkapp    Apr 19, 2021  From BAIR  Berkeley

Model-based reinforcement learning (MBRL) is a variant of the iterative learning framework, reinforcement learning, that includes a structured component of the system that is solely optimized to model the environment dynamics. Learning a model is broadly motivated from biology, optimal control, and more – it is grounded in natural human intuition of planning before acting. This intuitive grounding, however, results in a more complicated learning process. In this post, we discuss how model-based reinforcement learning is more susceptible to parameter tuning and how AutoML can help in finding very well performing parameter settings and schedules. Below, left is the expected behavior of an agent maximizing velocity on a “Half Cheetah” robotic task, and to the right is what our paper with hyperparameter tuning finds.

MBRL

Model-based reinforcement learning (MBRL) is an iterative framework for solving tasks in a partially understood environment. There is an agent that repeatedly tries to solve a problem, accumulating state and action data. With that data, the agent creates a structured learning tool – a dynamics model – to reason about the world. With the dynamics model, the agent decides how to act by predicting into the future. With those actions, the agent collects more data, improves said model, and hopefully improves future actions.  ... " 

Thursday, January 24, 2019

Technical Model Tuning

Nice technical piece which points at some of the 'art' of deep learning.  These are the kinds of near intuitive things that would have to be embedded in completely autonomous systems.   Sometimes we crowd-sourced these methods with multiple practitioners, when we sought other measures of variability.  Also, you are not always looking for optimization,  given other forms of  model variability.  So when I see the word optimize used I am cautious, since it always exists only in some context.   In the article, some good graphical systems provide intuitive directions.

An introduction to high-dimensional hyper-parameter tuning
Best practices for optimizing ML models     By Thalles Silva

If you ever struggled with tuning Machine Learning (ML) models, you are reading the right piece.

Hyper-parameter tuning refers to the problem of finding an optimal set of parameter values for a learning algorithm.

Usually, the process of choosing these values is a time-consuming task.

Even for simple algorithms like Linear Regression, finding the best set for the hyper-parameters can be tough. With Deep Learning, things get even worse.

Some of the parameters to tune when optimizing neural nets (NNs) include:  ... "