# Questions tagged [kullback-leibler]

An asymmetric measure of distance (or dissimilarity) between probability distributions. It might be interpreted as the expected value of the log likelihood ratio under the alternative hypothesis.

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### Is it possible to apply KL divergence between discrete and continuous distribution?

I am not a mathematician. I have searched the internet about KL Divergence. What I learned is the the KL divergence measures the information lost when we approximate distribution of a model with ...
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### Calculating Hellinger Divergence from Results of Kernel Density Estimates in Matlab

Using the ksdensity function in matlab returns a density estimation in the form of 2 vectors f and xi. Where f are the density values and xi the corresponding points for the density values. How do I ...
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### Kullback-Leibler vs Hellinger Distance

I am working on this problem in which I have a dataset of $n$-dimensional examples that come from different and unknown distributions. Given a new sample, I wish to find $k$ examples from the dataset ...
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### Estimating parameters using Kullback-Leibler or Kolmogorov-Smirnoff via Nelder-Mead

I want to find the parameters of a model which specifies a set of classification probabilities, for say M classes. (I'll use the parameters in another model later.) Given a set of parameters $\theta$,...
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### Logistic regression, loss function and KL divergence

In decision theory, a loss function signature is supposed to be output space * output space -> error There seems to be many different definition of 'the ...
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### On the uniform convergence of relative frequencies of events to their probabilities

I have read the article by Vapnik, Chervonenkis "On the uniform convergence of relative frequencies of events to their probabilities" Theory of Probability and Its Applications, vol XVI, n. , 1971. ...
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### Kullback-Leibler divergence: negative values? [duplicate]

Wikipedia - KL properties says that KL can never be negative. But e.g. for texts where the probabilities are very small I somehow get negative values? E.g. Collection A: - word count: 321 doc count:...
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### Hypothesis testing and total variation distance vs. Kullback-Leibler divergence

In my research I have run into the following general problem: I have two distributions $P$ and $Q$ over the same domain, and a large (but finite) number of samples from those distributions. Samples ...
2answers
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### Similarity / dissimilarity of two large bimodal datasets

I am interested in assessing the divergence, or similarity or dissimilarity of 2 datasets that are the results of 2 different lidar instrument measurements. Each dataset has over 90,000 values and ...
4answers
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### Measures of similarity or distance between two covariance matrices

Are there any measures of similarity or distance between two symmetric covariance matrices (both having the same dimensions)? I am thinking here of analogues to KL divergence of two probability ...
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### How to compute the Kullback-Leibler divergence when the PMF contains 0s?

I have the following timeseries obtained using the data posted below. For a sliding window size of 10, I am trying to compute the KL-divergence between the PMF of values within the current sliding ...
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### How do I determine how well a dataset approximates a distribution?

Quite simple, I have some probability distribution p(x), how can I measure whether one empirical density (set of delta masses) is a better approximation than another. I know that KL-divergence is a ...
0answers
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### How to to calculate the topic distribution of a document [closed]

I have a simple (may be stupid) question. I want to calculate Kullback–Leibler divergence on two documents. It requires probability distribution of each document. I do not know how to calculate ...
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### Kullback–Leibler divergence between two gamma distributions

Choosing to parameterize the gamma distribution $\Gamma(b,c)$ by the pdf $g(x;b,c) = \frac{1}{\Gamma(c)}\frac{x^{c-1}}{b^c}e^{-x/b}$ The Kullback-Leibler divergence between $\Gamma(b_q,c_q)$ and \$\...
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### Kullback–Leibler vs Kolmogorov-Smirnov distance

I can see that there are a lot of formal differences between Kullback–Leibler vs Kolmogorov-Smirnov distance measures. However, both are used to measure the distance between distributions. Is there a ...
2answers
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### KL divergence between two univariate Gaussians

I need to determine the KL-divergence between two Gaussians. I am comparing my results to these, but I can't reproduce their result. My result is obviously wrong, because the KL is not 0 for KL(p, p). ...
4answers
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### An adaptation of the Kullback-Leibler distance?

Look at this picture: If we draw a sample from the red density then some values are expected to be less than 0.25 whereas it is impossible to generate such a sample from the blue distribution. As a ...
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### Estimate the Kullback-Leibler divergence

I would like to be sure I am able to compute the KL divergence based on a sample. Assume the data come from a Gamma distribution with shape=1/.85 and scale=.85. set.seed(937) theta <- ....
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### Kullback-Leibler divergence - interpretation [duplicate]

I have a question about the Kullback-Leibler divergence. Can someone explain why the "distance" between the blue density and the "red" density is smaller than the distance between the "green" curve ...
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### Properties of Battacharyya distance vs Kullback-Leibler divergence

What properties do these measures have and how can I determine which one is better for a given purpose? What are extreme cases where they differ a lot?
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### What's good about I-projections?

There seems to be a large body of applied research where distribution q is picked to minimize KL(q,p) where p is empirical distribution. Are there theoretical reasons to prefer this estimator? For ...
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### Questions about KL divergence?

I am comparing two distributions with KL divergence which returns me a non-standardized number that, according to what I read about this measure, is the amount of information that is required to ...