Search found 401 matches

by marek [BayesFusion]
Thu Sep 08, 2022 6:52 pm
Forum: GeNIe
Topic: Adaptative time step in DBN inference
Replies: 4
Views: 88

Re: Adaptative time step in DBN inference

I'm afraid you will not be able to stop inference in a DBN in the middle, as we covert the DBN to a BN by unrolling and then run belief updating. You can control your inference by running it for a smaller number of steps, checking whether the condition that you were looking for has happened, and the...
by marek [BayesFusion]
Wed Sep 07, 2022 9:11 pm
Forum: GeNIe
Topic: Adaptative time step in DBN inference
Replies: 4
Views: 88

Re: Adaptative time step in DBN inference

I'm afraid GeNIe will not do automatically what you want to do. Perhaps you can try running the model at a rougher time step to figure out where interesting things are happening and then with a finer time step in places that you discover in the first run? If you do it through SMILE, it should not be...
by marek [BayesFusion]
Thu Sep 01, 2022 5:58 pm
Forum: SMILE
Topic: node evidence
Replies: 3
Views: 90

Re: node evidence

I am a little confused, as in the Bayesian networks world we call the probability tables that are the definition of a node CPTs, Conditional Probability Tables. They are indexed not by evidence but by the various combinations of the states of parents of the node. It is possible that they mean someth...
by marek [BayesFusion]
Mon Aug 29, 2022 3:30 pm
Forum: SMILE
Topic: node evidence
Replies: 3
Views: 90

Re: node evidence

Hi Sara, "Evidence" is a very basic term in Bayesian inference and denotes an observation of a concrete state of a node. Your question is about SMILE programming and there are most certainly people at BayesFusion and outside who know more than I do about SMILE programming. You can get exam...
by marek [BayesFusion]
Tue Aug 16, 2022 8:25 pm
Forum: SMILE
Topic: the representation of the bayesian network in a meta ontology
Replies: 1
Views: 102

Re: the representation of the bayesian network in a meta ontology

Hi Sara, I would be happy to help but you are using vocabulary that I am not really familiar with. What do you mean by "meta model"? What do you mean by "instantiating" a Bayesian network? In the Bayesian network world, it usually means assigning values to an existing Bayesian ne...
by marek [BayesFusion]
Tue Aug 09, 2022 7:33 pm
Forum: GeNIe
Topic: Promblem with mapping fault tree into bayesian network on GeNIe
Replies: 1
Views: 65

Re: Promblem with mapping fault tree into bayesian network on GeNIe

Your error is assuming that E1 and E2 are independent. They are not, as they have a common ancestor, b. Because they are dependent, you cannot just multiply probabilities as you did in your calculation.

I hope this helps,

Marek
by marek [BayesFusion]
Wed Jul 27, 2022 6:25 am
Forum: SMILE
Topic: PCTs updates
Replies: 1
Views: 181

Re: PCTs updates

Absolutely! Start with "Learning parameters" from the "Learning" menu. In the "Learn Parameters with EM" dialog, select "Keep original" (parameters) and give the existing data a confidence level that corresponds to the number of records that the existing param...
by marek [BayesFusion]
Wed Jul 13, 2022 10:37 am
Forum: GeNIe
Topic: Is there a way to instantiate general variables in probability tables of discrete nodes?
Replies: 2
Views: 110

Re: Is there a way to instantiate general variables in probability tables of discrete nodes?

I'm afraid you cannot do this in GeNIe. The fastest way would be copying and pasting the entire table from the source to the destination nodes. This, I'm afraid, is not what you would like. It seems to me that you should program this in your favorite programming language and use SMILE. This will be ...
by marek [BayesFusion]
Fri Jul 08, 2022 3:56 pm
Forum: GeNIe
Topic: Inquiries regarding sampling methods used by SMILE engine
Replies: 2
Views: 109

Re: Inquiries regarding sampling methods used by SMILE engine

Hi Juan Luis, Thank you for your kind words about GeNIe and SMILE -- we have been trying our best to develop a flexible and useful tool for the academic and commercial communities. You will find the GIS capabilities included in the most recent release of GeNIe (4.0) very useful in environmental work...
by marek [BayesFusion]
Thu Jun 30, 2022 9:09 pm
Forum: GeNIe
Topic: Too many states in nature nodes
Replies: 3
Views: 143

Re: Too many states in nature nodes

I roughly see what you want to accomplish. I'm afraid your CPT in node PorductHierarchyID will have 40,000 conditional probability distributions and given that the node itself has 50 states, it will have 2,000,000 probabilities. If you multiply these by 8 bytes needed to represent a floating point n...
by marek [BayesFusion]
Tue Jun 28, 2022 7:16 pm
Forum: GeNIe
Topic: Too many states in nature nodes
Replies: 3
Views: 143

Re: Too many states in nature nodes

Generally, probabilistic representations are wonderfully efficient but only if there are independencies in the domain. Still, probability tables grow exponentially with the number of parents. The base of the exponent is the number of states in the node and parents. Having a node with thousands of st...
by marek [BayesFusion]
Tue Jun 21, 2022 7:15 pm
Forum: GeNIe
Topic: randomize parameter
Replies: 2
Views: 141

Re: randomize parameter

Hi Yan, I believe you are asking about randomization in the context of the EM algorithm (please correct me if I am wrong). In validation, this parameter also refers to the EM algorithm part (learning the parameters at each cross-validation step). It is an empirical finding that randomization gets yo...
by marek [BayesFusion]
Thu Jun 16, 2022 11:39 am
Forum: GeNIe
Topic: Help with influence diagram
Replies: 4
Views: 162

Re: Help with influence diagram

Clearly, your influence diagram is too complex. Please keep in mind that probabilistic inference is worst case NP-hard and it is not that difficult to construct models that are not computable. Quite likely if a model cannot be solved by SMILE/GeNIe, you cannot solve it with any software on Earth. Th...
by marek [BayesFusion]
Tue Jun 14, 2022 3:08 pm
Forum: GeNIe
Topic: Help with influence diagram
Replies: 4
Views: 162

Re: Help with influence diagram

Your model is quite impressive (in terms of size and complexity). I am not sure you can solve it using our default ID algorithm, as it will involve calculating the expected utilities over 2^19 (524,288) different policies. This is, of course, when you change back the RCM* nodes to decision nodes. Ar...
by marek [BayesFusion]
Thu Jun 09, 2022 6:51 pm
Forum: GeNIe
Topic: query about noisyMAX algorithm
Replies: 9
Views: 427

Re: query about noisyMAX algorithm

I see. I misunderstood your example but have have clarified it sufficiently. When A and B have an unobserved common parent C, you can write the following: P(A,B)=Sigma_over_i P(A|B,C_i)P(B|C_i)P(C_i) You write this formula for all possible states of C_i. Because both A and B are dependent on C, you ...