All Questions
Tagged with dirichlet-distribution machine-learning
21
questions
3
votes
1
answer
814
views
How to generate data from a generalized Dirichlet distribution?
I need to generate data from a generalized Dirichlet distribution in Python to test my model, but I have no idea how can I proceed with that, can anyone guide me?
- 33
1
vote
0
answers
174
views
Log-likelihood of a finite mixture distribution (PDF overflowing)
I'm trying to use a finite mixture of Dirichlet distributions in a project, but am encountering problems with the PDF becoming so large for input values close to 0 that it overflows to infinity (as ...
- 151
2
votes
1
answer
850
views
could someone please give a concrete example to illustrate the Dirichlet distribution prior for bag-of-words?
I am aware of the notion of the Dirichlet distribution, a multivariate generalization of the beta distribution.
To get parameters of the Dirichlet distribution prior for bag-of-words, this CMU ...
- 1,995
2
votes
1
answer
191
views
Bayesian inference out of partial information - Dirichlet example
Suppose we have two coins $X_1$ and $X_2$. They are possibly biased and correlated coins. The heads probability of each coins is denoted by $p_1$ and $p_2$ which we don't know at the beginning. The ...
- 433
19
votes
2
answers
8k
views
Purpose of Dirichlet noise in the AlphaZero paper
In DeepMind's AlphaGo Zero and AlphaZero papers, they describe adding Dirichlet noise to the prior probabilities of actions from the root node (board state) in Monte Carlo Tree Search:
Additional ...
- 475
6
votes
2
answers
4k
views
Find marginal distribution of $K$-variate Dirichlet
I've already seen https://math.stackexchange.com/questions/1064995/marginal-of-dirichlet-distribution-is-beta-integral, but need to extend this to the $K$-variate case.
We have $\mathbf{x} = \begin{...
- 5,077
1
vote
0
answers
101
views
For Latent Dirichlet Allocation, why is setting alpha to a very low value equivalent to having a mixture model?
I'm watching a video on topic modeling by David Blei (from 27:00 of Part 2) and I don't understand how setting the $\alpha$ hyperparameter to a value close to zero basically results in a mixture model ...
- 111
1
vote
0
answers
69
views
Utilising the reparameterisation trick on non-Gaussian distributions (Dirichlet)
I'm specifically looking to apply the trick to a Dirichlet distribution. Kingma and Welling (2013) briefly talk about how the trick can be applied to non-Gaussian distributions, and state that the ...
- 175
1
vote
0
answers
134
views
How to sample weights for weighted kernels?
I'm using a SVM classifier with a weighted RBF kernel. My dataset has 17 features. In the RBF kernel I will use a weight for each feature. Of course the weights must sum to one. For choosing the best ...
- 299
1
vote
1
answer
96
views
About LDA model, I need a true expert to tell me that what is the real benefits of the Dirichlet prior? [closed]
Well,you know ,the only difference between pLSI and LDA is that the latter has a Dirichlet prior,thus the number of model parameters do not increase with the size of corpus,and this avoid the ...
- 191
0
votes
1
answer
52
views
What is an assignment matrix?
I'm trying to implement a topic model using a Latent Dirichlet allocation (LDA) algorithm. I'm using sentences as my dataset. What is Ck in the given instructions?
The instructions are as follows:
...
- 113
2
votes
2
answers
839
views
Difference between hierarchical dirichlet process and nested dirichlet process
There have some extensions to Dirichlet process. One is Hierarchical Dirichlet process, and another is Nested Dirichlet Process. What are the differences between these two?
I once read the paper of ...
- 5,222
5
votes
1
answer
2k
views
understanding of effect of $\alpha$ in Dirichlet distribution
When reading the topic modeling tutorial written by Blei, KDD 2011 tutorial I was confused about a set of diagrams which aim to show the effect of $\alpha$ in Dirichlet distribution.
For example, for ...
- 5,222
1
vote
0
answers
92
views
What to do for Dirichlet distribution when elements of X vector may be zero
So I want to define a Dirichlet distribution over frequency vectors which are unit vectors whose elements represent the frequency with which different characters occur in a body of text. Trouble is ...
- 121
3
votes
0
answers
374
views
Dirichlet process mixture model with Bayesian hierarchical clustering
I am doing Bayesian hierarchical clustering. From my understanding, there are three basic points for this algorithm.
Use marginal likelihoods to decide which clusters to merge
Asks what the ...
- 5,222