Important: Read this before posting to this forum
- This forum is for questions related to the use of Apollo. We will answer some general choice modelling questions too, where appropriate, and time permitting. We cannot answer questions about how to estimate choice models with other software packages.
- There is a very detailed manual for Apollo available at http://www.ApolloChoiceModelling.com/manual.html. This contains detailed descriptions of the various Apollo functions, and numerous examples are available at http://www.ApolloChoiceModelling.com/examples.html. In addition, help files are available for all functions, using e.g. ?apollo_mnl
- Before asking a question on the forum, users are kindly requested to follow these steps:
- Check that the same issue has not already been addressed in the forum - there is a search tool.
- Ensure that the correct syntax has been used. For any function, detailed instructions are available directly in Apollo, e.g. by using ?apollo_mnl for apollo_mnl
- Check the frequently asked questions section on the Apollo website, which discusses some common issues/failures. Please see http://www.apollochoicemodelling.com/faq.html
- Make sure that R is using the latest official release of Apollo.
- Users can check which version they are running by entering packageVersion("apollo").
- Then check what is the latest full release (not development version) at http://www.ApolloChoiceModelling.com/code.html.
- To update to the latest official version, just enter install.packages("apollo"). To update to a development version, download the appropriate binary file from http://www.ApolloChoiceModelling.com/code.html, and install the package from file
- If the above steps do not resolve the issue, then users should follow these steps when posting a question:
- provide full details on the issue, including the entire code and output, including any error messages
- posts will not immediately appear on the forum, but will be checked by a moderator first. This may take a day or two at busy times. There is no need to submit the post multiple times.
Search found 9 matches
- 12 Nov 2023, 00:21
- Forum: Estimation results
- Topic: Why can I get s.e. from BHHH matrix (when I run BFGS), but the numerical derivation produces NAN?
- Replies: 3
- Views: 35591
Re: Why can I get s.e. from BHHH matrix (when I run BFGS), but the numerical derivation produces NAN?
Hi Stephane, I run an EMDC model with latent class (say there are two latent segments, the membership of which is associated with demographics, and each segment has a different set of parameters for the baseline utility and the satiation parameters). I tried to use the default BGW algorithm for opti...
- 04 Nov 2023, 06:03
- Forum: Model estimation
- Topic: How to change the setting of delta matrix (for complementarity)
- Replies: 7
- Views: 51670
Re: How to change the setting of delta matrix (for complementarity)
Hi David, Thank you very much for your reply! I have been doing some debugging. I now have a few follow-up questions/clarifications: 1. In my panel data, I have about 500 individuals and about 25000 observations in total. Instead of using random coefficients, I use a latent class framework similar t...
- 29 Sep 2023, 04:58
- Forum: Estimation results
- Topic: Why can I get s.e. from BHHH matrix (when I run BFGS), but the numerical derivation produces NAN?
- Replies: 3
- Views: 35591
Why can I get s.e. from BHHH matrix (when I run BFGS), but the numerical derivation produces NAN?
Hi, Thank you for providing so much help on this forum! I have a general question when running an EMDC model embedded in a latent class framework. When the estimation is done (showing converged), it shows estimated parameters with approximate standard errors from BHHH matrix, which is all fine. Howe...
- 25 Sep 2023, 10:04
- Forum: Model estimation
- Topic: How to change the setting of delta matrix (for complementarity)
- Replies: 7
- Views: 51670
Re: How to change the setting of delta matrix (for complementarity)
Hi David, Thank you very much for your reply. I tried your approach and it works! I have another question related to this model. I tried to estimate a more complicated model (with EMDC model embedded in a latent class framework). I tried to use BFGS estimation. Everything worked fine in the estimati...
- 25 Aug 2023, 22:08
- Forum: Model estimation
- Topic: How to change the setting of delta matrix (for complementarity)
- Replies: 7
- Views: 51670
Re: How to change the setting of delta matrix (for complementarity)
Hi David, Thank you so much for your quick response. I really appreciate it. I understand that systematic variation of preferences is allowed (say the complementarity/substitution patterns vary between different consumers based on their demographics). My question is a bit more complicated than that....
- 25 Aug 2023, 02:32
- Forum: Model estimation
- Topic: How to change the setting of delta matrix (for complementarity)
- Replies: 7
- Views: 51670
How to change the setting of delta matrix (for complementarity)
In the context of the eMDC model, I've noticed that the delta matrix for substitutability/complementarity remains consistent across all observations. However, due to the complexity of my data construction, I need the flexibility to modify this matrix between observations. To illustrate, consider a s...
- 28 Oct 2021, 06:40
- Forum: Post-estimation analysis/use of results
- Topic: MDCEV model prediction error
- Replies: 3
- Views: 6083
Re: MDCEV model prediction error
Hi Stephane, Thank you for your quick response. I was trying to do some debug myself. I think the problem occurs when a latent class is added to the MDCEV model. Within the prediction function, apollo_probabilities uses the function "prediction" rather than "estimate". But P[[pas...
- 26 Oct 2021, 19:37
- Forum: Post-estimation analysis/use of results
- Topic: MDCEV model prediction error
- Replies: 3
- Views: 6083
MDCEV model prediction error
Hi all, I tried to do a model prediction using predictions_base = apollo_prediction(model, apollo_probabilities, apollo_inputs ) right after I finish estimating the model. It works for the model I estimated without a latent class. However, after I added the latent class to the MDCEV model and run th...
- 28 Aug 2021, 02:20
- Forum: Model specification
- Topic: MDCEV model with time/individual specific covariates in gamma?
- Replies: 5
- Views: 8425
MDCEV model with time/individual specific covariates in gamma?
Hi all, I am trying to estimate an MDCEV (discrete-continuous model) similar to Apollo_example_12.r, but with an extension. In the example, the gamma (satiation) parameter is alternative j specific, gamma_j. Is there any way that I can add a time/individual and alternative variant covariates (Xijt) ...