Important: Read this before posting to this forum

  1. 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.
  2. 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
  3. Before asking a question on the forum, users are kindly requested to follow these steps:
    1. Check that the same issue has not already been addressed in the forum - there is a search tool.
    2. 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
    3. Check the frequently asked questions section on the Apollo website, which discusses some common issues/failures. Please see http://www.apollochoicemodelling.com/faq.html
    4. Make sure that R is using the latest official release of Apollo.
  4. If the above steps do not resolve the issue, then users should follow these steps when posting a question:
    1. provide full details on the issue, including the entire code and output, including any error messages
    2. posts will not immediately appear on the forum, but will be checked by a moderator first. We check the forum at least twice a week. It may thus take a couple of days for your post to appear and before we reply. There is no need to submit the post multiple times.

Search found 2 matches

by Feli
18 Jul 2024, 12:43
Forum: Errors during model validation and/or estimation.
Topic: MNL model: "Warning: Estimation failed. No covariance matrix to compute.”
Replies: 3
Views: 26688

Re: MNL model: "Warning: Estimation failed. No covariance matrix to compute.”

Dear Stephane,

regarding the second problem: the data I posted here is only a minimal example that mirrors the structure of my actual data and that reproduces the issues with the model. My actual data is a table consisting of about 3000 rows and 30 columns (though only two of the columns are ...
by Feli
27 Jun 2024, 13:10
Forum: Errors during model validation and/or estimation.
Topic: MNL model: "Warning: Estimation failed. No covariance matrix to compute.”
Replies: 3
Views: 26688

MNL model: "Warning: Estimation failed. No covariance matrix to compute.”

Dear Prof. Hess,

thank you for answering questions on here! This is my first time using the apollo package (and the first time posting on a forum like this…) and I am having issues with a warning message “Warning: Estimation failed. No covariance matrix to compute.” The model is supposed to be an ...