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Jan
24
accepted How to test the convexity of mutual information using leading principal minors?
Jan
24
comment How to test the convexity of mutual information using leading principal minors?
oic, thank you for your wonderful insights.
Jan
23
comment How to test the convexity of mutual information using leading principal minors?
thank you for your explanations, I tried again to solve via a simpler Hessian matrix, as shown in my above edits, but still can't get the solution. Do you have any idea why is it so?
Jan
23
revised How to test the convexity of mutual information using leading principal minors?
added 800 characters in body
Jan
23
asked How to test the convexity of mutual information using leading principal minors?
Jan
18
awarded  Commentator
Jan
18
comment How to differentiate discrete probabilities?
Thank you very much for your help, much appreciated
Jan
18
comment How to differentiate discrete probabilities?
@joriki: yes. I haven't think in depth about the problem. I'm thinking since the constraint is linear, I can use the elimination of variable method to simplify the constrained optimization problem into an unconstrained optimization problem
Jan
18
comment How to differentiate discrete probabilities?
@joriki: thank you very much for your help. I will be careful in the future. Can you elaborate more on the normalization constraint?
Jan
18
awarded  Scholar
Jan
18
accepted How to differentiate discrete probabilities?
Jan
18
comment How to differentiate discrete probabilities?
I am so sorry, I try to add more explanations now. =)
Jan
18
revised How to differentiate discrete probabilities?
added 139 characters in body
Jan
18
comment How to differentiate discrete probabilities?
@joriki: I think your total derivative is what I needed, and with the relationship $p(x) = \sum_c p(x,c)$, $p(c) = \sum_x p(x,c)$, I can plug these relationships into your total derivative to get my gradient
Jan
18
revised How to differentiate discrete probabilities?
added 28 characters in body
Jan
18
comment How to differentiate discrete probabilities?
@joriki: I apologise for missing the details. So given that I have $p(x)=\sum_c p(x,c)$ (thank you Ilya), I can differentiate $\frac{\partial p(x)}{\partial p(x,c')}=\frac{\partial \sum_c p(x,c)}{\partial p(x,c')}$?
Jan
18
comment How to differentiate discrete probabilities?
I only know the $p(x,c)$ is the joint probability of random variable $x,c$. Is there a way to express $p(x),p(c)$ as function of $p(x,c)$?
Jan
18
revised How to differentiate discrete probabilities?
edited body
Jan
18
comment How to differentiate discrete probabilities?
@Ilya my function is to measure a characteristic of the data, and I am wondering what will be the optimal probabilities to get the maximum of the function, or if given a probability, what is the gradient of the function to reach the maximum of the function, To get the maximum of the function, I am thinking of getting its gradient
Jan
18
comment How to differentiate discrete probabilities?
The discrete probabilities are simply obtained from a discrete data. I am not familiar with partial derivatives. My guess is differentiate $ln (p(x)p(c))$ wrt $p(c,x)$ is zero, but it seems that $p(x)p(c)$ and $p(x,c)$ are related, but they are not governed by a formula or equation, so I do not know how to do partial differentiation on them