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 7 matches
- 22 Sep 2021, 16:47
- Forum: Errors during model validation and/or estimation.
- Topic: Multinomial logit estimation gets stuck
- Replies: 6
- Views: 7857
Re: Multinomial logit estimation gets stuck
Thank you Stephane, I certainly appreciate that you added this setting for me. I ran the estimation, and everything worked out quickly, with the estimation successfully skipping LL(c) calculation part. This was a huge relief, thank you! I have a small comment that is also related to having some alte...
- 22 Sep 2021, 01:45
- Forum: Errors during model validation and/or estimation.
- Topic: Multinomial logit estimation gets stuck
- Replies: 6
- Views: 7857
Re: Multinomial logit estimation gets stuck
I investigated the issue a bit further. The problem stems from the restriction on choices. Any of the following allows for very quick estimation without the computation getting stuck: - restricting the sample to only one third of individuals who are allowed to choose from 408 alternatives (or the se...
- 21 Sep 2021, 16:54
- Forum: Errors during model validation and/or estimation.
- Topic: Multinomial logit estimation gets stuck
- Replies: 6
- Views: 7857
Re: Multinomial logit estimation gets stuck
Hi Stephane, There are three groups of alternatives. Each individual can only choose from one group of alternatives (this is specified through A). The total number of alternatives is 408 + 410 + 450 (three groups) = 1268. There are about 12000 individuals in each group, so 36000 total. I use 200Gb o...
- 18 Sep 2021, 04:00
- Forum: Model specification
- Topic: Iterative coding of utilities fails (only when nCores > 1)
- Replies: 2
- Views: 4538
Re: Iterative coding of utilities fails (only when nCores > 1)
Hi David, Many thanks for your answer. I was using 12 nodes The error I was getting was: Error in checkForRemoteErrors(lapply(cl, recvResult)) : 12 nodes produced errors; first error: object 'list_alt' not found The solution is simple: the object list_alt should be defined inside apollo_probabilitie...
- 17 Sep 2021, 23:45
- Forum: Errors during model validation and/or estimation.
- Topic: Multinomial logit estimation gets stuck
- Replies: 6
- Views: 7857
Multinomial logit estimation gets stuck
I am estimating a multinomial logit model. I use the simplest specification similar to Example 3, just to see if I specify everything correctly. My data has many individuals choosing many locations, and so I define the utilities and the availability objects (V and A) using a lot of get() statements,...
- 30 Aug 2021, 20:49
- Forum: Model specification
- Topic: Choice sets with large numbers of alternatives
- Replies: 8
- Views: 12388
Re: Choice sets with large numbers of alternatives
This solution by David assumes that altName object can be built as altName = paste0("alt",j). This requires that all alternatives have simple names (in this example, alt1, alt2 etc.) I am working with a large choice model with many choices with complicated names. My choice is cities, like ...
- 29 Aug 2021, 23:19
- Forum: Model specification
- Topic: Iterative coding of utilities fails (only when nCores > 1)
- Replies: 2
- Views: 4538
Iterative coding of utilities fails (only when nCores > 1)
I am trying to estimate a nested logit model with 900 alternatives. 3000 individuals with a single child choose places to live (upper nest) and whether the child goes to school (lower nest). I understand nested logit is not ideal for modeling sequential choices, but my issue is model specification i...