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 4 matches
- 05 Apr 2024, 14:50
- Forum: Errors during model validation and/or estimation.
- Topic: No covariance matrix
- Replies: 5
- Views: 1136
Re: No covariance matrix
another addition: I got it to work by first running a model with only the linear components (the beta's and parameters with a 'a', for example: BETA_costa in my model) and then taking those estimated betas for defining the starting values of the linear components (BETA_costa in my model) in the mode...
- 04 Apr 2024, 19:49
- Forum: Errors during model validation and/or estimation.
- Topic: No covariance matrix
- Replies: 5
- Views: 1136
Re: No covariance matrix
Unfortunately, even though i fixed the MNL model, I run into a similar error trying to estimate a mixed logit model. I have used the same functions and beta's as specified in the working MNL model. Additionally I have added a sigma_app for both app alternatives to capture their unobserved common fac...
- 02 Apr 2024, 16:37
- Forum: Errors during model validation and/or estimation.
- Topic: No covariance matrix
- Replies: 5
- Views: 1136
Re: No covariance matrix
Hi Stephane,
Thank you for your quick reply. My 7 attributes all have 3 categorical levels.
However, I think the mistake was due to a typo that slipped through, I used a '+' where i should have multiplied the beta and the parameter.
Thanks anyway
Thank you for your quick reply. My 7 attributes all have 3 categorical levels.
However, I think the mistake was due to a typo that slipped through, I used a '+' where i should have multiplied the beta and the parameter.
Thanks anyway
- 01 Apr 2024, 15:59
- Forum: Errors during model validation and/or estimation.
- Topic: No covariance matrix
- Replies: 5
- Views: 1136
No covariance matrix
I am trying to estimate a MNL model with 7 app attributes that have three levels. All the attributes are effect coded with two parameters (for example, cost --> costa & costb). I have also included a 'opt out' option, which was phrased as 'prefer to download no app at all' and is utility functio...