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 18 matches
- 02 Sep 2022, 21:29
- Forum: Bug reports
- Topic: Bug in HB estimation
- Replies: 1
- Views: 6709
Bug in HB estimation
Hi, When I try to estimate a model, I get the following error: Error in rowsum.default(log(tmp[[s]]), group = indivID, reorder = FALSE) : incorrect length for 'group' I sent the code and data offline. I believe the issue has something to do with there only being one random variable with a fixed mean...
- 16 Dec 2021, 13:34
- Forum: Bug reports
- Topic: Major difference between frequentist and HB results for apollo_mnl component
- Replies: 5
- Views: 10450
Re: Major difference between frequentist and HB results for apollo_mnl component
Stephane,
I can't figure out how exactly a very high z_i would fit the model better. I'll let you know if I find more information, and please let me know if you'd like to look into it yourself.
Tomás
I can't figure out how exactly a very high z_i would fit the model better. I'll let you know if I find more information, and please let me know if you'd like to look into it yourself.
Tomás
- 15 Dec 2021, 20:28
- Forum: Bug reports
- Topic: Major difference between frequentist and HB results for apollo_mnl component
- Replies: 5
- Views: 10450
Re: Major difference between frequentist and HB results for apollo_mnl component
Hi Stephane,
So sorry, I just realized it was a mistake on my part. In the MNL settings, I specified ows (no r) instead of rows. I guess that produced some kind of mistake in the sampling procedure.
It might be useful to have some kind of error message for this in the future.
Thanks again
So sorry, I just realized it was a mistake on my part. In the MNL settings, I specified ows (no r) instead of rows. I guess that produced some kind of mistake in the sampling procedure.
It might be useful to have some kind of error message for this in the future.
Thanks again
- 15 Dec 2021, 15:49
- Forum: Bug reports
- Topic: Major difference between frequentist and HB results for apollo_mnl component
- Replies: 5
- Views: 10450
Major difference between frequentist and HB results for apollo_mnl component
Hi David and Stephane, I am estimating two ICLVs (different data and model specifications) where at least one of the indicators I'm interested in is a binary outcome. The measurement function for that indicator is a binary logit, and the "utility" is equal to U = c_0 + z_1 * LV. I'm also u...
- 28 Sep 2021, 14:09
- Forum: Models and estimation
- Topic: Scaling when HB == TRUE?
- Replies: 1
- Views: 5200
Scaling when HB == TRUE?
Hi,
I know that scaling is important using classical estimation because very large or small numbers can introduce issues into matrix manipulation. Is it as important in a Bayesian setting?
Thanks!
I know that scaling is important using classical estimation because very large or small numbers can introduce issues into matrix manipulation. Is it as important in a Bayesian setting?
Thanks!
- 28 Apr 2021, 19:44
- Forum: Model specification
- Topic: Custom random parameters in HB
- Replies: 1
- Views: 3731
Custom random parameters in HB
Hi, I'm estimating an HB mixed logit model. I'd like to specify some parameters to follow a distribution that is not one of the ones included in the RSGHB package. I'd specifically like to build a Bernoulli random variable. In classical estimation, what I would do is define a Normal random error com...
- 30 Mar 2021, 13:07
- Forum: Bug reports
- Topic: Error in HB model with JSB variables
- Replies: 2
- Views: 8571
Re: Error in HB model with JSB variables
Thank you Stephane!
- 26 Mar 2021, 18:29
- Forum: Bug reports
- Topic: Error in HB model with JSB variables
- Replies: 2
- Views: 8571
Error in HB model with JSB variables
Hi Stephane and David, I'm trying to estimate a model where HB == TRUE and one of the parameters distributes JSB between 0 and 1. Unfortunately, an error message keeps popping up. Here's a part of a reproducible example using apollo_modeChoiceData: [database, etc.] apollo_beta=c(asc_car = 0, asc_bus...
- 17 Mar 2021, 22:03
- Forum: Errors during model validation and/or estimation.
- Topic: Error when estimating a ICLV model with two sources of information
- Replies: 11
- Views: 11277
Re: Error when estimating a ICLV model with two sources of information
Hi David and Stephane,
I also bumped into this issue when I tried to use more than one core (nCores = 1 works fine). This happened in a Mac and a Windows machine running Apollo v0.2.4. If you haven't been able to track down the problem, I can also share my code and dataset.
Thanks,
Tomás
I also bumped into this issue when I tried to use more than one core (nCores = 1 works fine). This happened in a Mac and a Windows machine running Apollo v0.2.4. If you haven't been able to track down the problem, I can also share my code and dataset.
Thanks,
Tomás
- 22 Feb 2021, 15:03
- Forum: Models and estimation
- Topic: Very large standard errors
- Replies: 1
- Views: 4588
Very large standard errors
Hi, I'm estimating a multinomial logit model that has many observations per individual (4,303 observations, 46 individuals, 20 alternatives). An extremely simple model (ASCs + one alternative-specific parameter) produces very large robust standard errors. What could be the source of this issue? Some...