MullOverThing

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# How is KL divergence used in machine learning?

## How is KL divergence used in machine learning?

¶ The Kullback-Leibler divergence (hereafter written as KL divergence) is a measure of how a probability distribution differs from another probability distribution. In this context, the KL divergence measures the distance from the approximate distribution Q to the true distribution P .

## What is the difference between KL divergence and cross entropy?

Cross-Entropy Versus KL Divergence Cross-entropy is not KL Divergence. Cross-entropy is related to divergence measures, such as the Kullback-Leibler, or KL, Divergence that quantifies how much one distribution differs from another. Specifically, the KL divergence measures a very similar quantity to cross-entropy.

Is KL divergence positive?

The KL divergence is non-negative if P≠Q, the KL divergence is positive because the entropy is the minimum average lossless encoding size.

Where is KL divergence loss used?

Since KL divergence works with probability distributions, it’s very much usable here. Funnily, KL divergence is also used for replacing Least Squares minimization in models (Kosheleva & Kreinovich, 2018). In regression models, the loss function to minimize is usually the error (prediction minus target), often squared.

### Why is cross entropy better than MSE?

Practical understanding: First, Cross-entropy (or softmax loss, but cross-entropy works better) is a better measure than MSE for classification, because the decision boundary in a classification task is large (in comparison with regression). For regression problems, you would almost always use the MSE.

### What is KL divergence loss?

It’s hence not surprising that the KL divergence is also called relative entropy. It’s the gain or loss of entropy when switching from distribution one to distribution two (Wikipedia, 2004) – and it allows us to compare two probability distributions.

How do you interpret KL divergence value?

KL divergence can be calculated as the negative sum of probability of each event in P multiplied by the log of the probability of the event in Q over the probability of the event in P. The value within the sum is the divergence for a given event.

Why KL divergence is not a metric?

Although the KL divergence measures the “distance” between two distri- butions, it is not a distance measure. This is because that the KL divergence is not a metric measure. It is not symmetric: the KL from p(x) to q(x) is generally not the same as the KL from q(x) to p(x).

## How is KL divergence used in the real world?

Intuition: KL divergence is a way of measuring the matching between two distributions (e.g. threads) So we could use the KL divergence to make sure that we matched the true distribution with some s imple-to-explain and well-known distribution well. Let’s change a few things in the example

## Is the Kullback Leibler divergence a KL divergence?

This post will talk about the Kullback-Leibler Divergencefrom a holistic perspective of reinforcement learning and machine learning. You’ve probably run into KL divergences before: especially if you’ve played with deep generative models like VAEs.

What is the KL divergence between two probability distributions?

Put simply, the KL divergence between two probability distributions measures how different the two distributions are. I’ll introduce the definition of the KL divergence and various interpretations of the KL divergence. Most importantly, I’ll argue the following fact:

How is the KL divergence used in Bayesian theory?

Classically, in Bayesian theory, there is some true distribution\$P(X)\$; we’d like to estimate with an approximate distribution\$Q(X)\$. In this context, the KL divergence measures the distance from the approximate distribution \$Q\$ to the true distribution \$P\$.