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 14 matches
- 03 Nov 2022, 15:54
- Forum: Errors during model validation and/or estimation.
- Topic: Error in apollo_modifyUserDefFunc(apollo_beta, apollo_fixed, apollo_probabilities)
- Replies: 1
- Views: 1160
Error in apollo_modifyUserDefFunc(apollo_beta, apollo_fixed, apollo_probabilities)
Dear Sir, I hope you are doing well. I would like to estimate income effects in my simple MNL model. However, when running the codes, R reported an error indicating that a parameter (b_fare_bus) from apollo_beta was re-defined inside apollo_probabilities, which is not allowed. I have checked my code...
- 18 Oct 2022, 18:31
- Forum: Errors during model validation and/or estimation.
- Topic: An intercept parameter does not influence the log-likehood of my model after adding a new dataset
- Replies: 2
- Views: 1271
An intercept parameter does not influence the log-likehood of my model after adding a new dataset
Hi Stephane, I hope you are doing well. I am confused about this problem because the model estimation in R went well using the first part of my dataset. However, after adding the other part of the dataset, an error was reported in R, as my title states. My utility functions are written in using brac...
- 21 May 2020, 17:27
- Forum: Model specification
- Topic: How to choose random parameters for MMNL model
- Replies: 3
- Views: 5983
Re: How to choose random parameters for MMNL model
Hi Stephane, Thank you for your detailed reply. As you suggest, I incorporated socio-demographic factors into the Mixed MNL model, while assuming all parameters were random. From the analysis results, I found that some of the parameters were statistically significant based on their estimated standar...
- 14 May 2020, 17:45
- Forum: Model specification
- Topic: How to choose random parameters for MMNL model
- Replies: 3
- Views: 5983
How to choose random parameters for MMNL model
Dear Sir, I attended your incredible Apollo course last November in London. Now, I am using Apollo to analysis my data. However, I am confused about which parameters should be chosen as random parameters in MMNL model. Should I only choose those parameters which were statistically significant in MNL...