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 11 matches
- 13 Sep 2023, 18:20
- Forum: Errors during model validation and/or estimation.
- Topic: Only single alternative is available for RP data
- Replies: 1
- Views: 2896
Only single alternative is available for RP data
Dear Prof. Hess and Dr. Palma, I'm struggling with my joint RP-SP (Revealed Preference-Stated Preference) mode choice model for an upcoming study. In my RP data, I only have information on travel time and cost for single alternatives (car users). In the SP scenario, I'm looking at improvements in th...
- 29 Aug 2023, 20:17
- Forum: Model specification
- Topic: Nested logit model with ranked choice
- Replies: 2
- Views: 3995
Re: Nested logit model with ranked choice
Thankyou for David for prompt response.
- 29 Aug 2023, 12:08
- Forum: Models and estimation
- Topic: Zero inflated negative bonomial hybrid choice model
- Replies: 1
- Views: 3215
Zero inflated negative bonomial hybrid choice model
Dear Sir,
My dependent variable is count data. I also have latent variables as independent. Could you please suggest if it is possible to develop a zero inflated negative binomial based hybrid choice model in Apollo?
If yes then could you please share sample codes for the same?
My dependent variable is count data. I also have latent variables as independent. Could you please suggest if it is possible to develop a zero inflated negative binomial based hybrid choice model in Apollo?
If yes then could you please share sample codes for the same?
- 06 Jun 2023, 18:06
- Forum: Feature requests
- Topic: Request to add copula-based joint model codes
- Replies: 1
- Views: 11041
Request to add copula-based joint model codes
Dear Professor Hess and Dr. Palma I hope you are doing well. I would request you to kindly add codes and function for copula-based joint model in Apollo. Additionally, it will be very helpful if this model can be depicted in upcoming manual along with an example related to transportation planning. T...
- 08 Mar 2023, 11:05
- Forum: Errors during model validation and/or estimation.
- Topic: Error in estimating MDCEV model with RP&SP data
- Replies: 4
- Views: 1446
Re: Error in estimating MDCEV model with RP&SP data
Thank you Prof. Hess for solving the issue. The code is working fine now.
Thank you for developing this amazing and powerful package 'Apollo'.
Thank you for developing this amazing and powerful package 'Apollo'.
- 06 Mar 2023, 16:39
- Forum: Errors during model validation and/or estimation.
- Topic: Error in estimating MDCEV model with RP&SP data
- Replies: 4
- Views: 1446
Re: Error in estimating MDCEV model with RP&SP data
Thank You Prof. Hess.
I have shared the data and code at the mentioned email.
I have shared the data and code at the mentioned email.
- 17 Feb 2023, 18:08
- Forum: Errors during model validation and/or estimation.
- Topic: Error in estimating MDCEV model with RP&SP data
- Replies: 4
- Views: 1446
Error in estimating MDCEV model with RP&SP data
Dear Sir, For my research work, I need to develop models with pooled RP&SP data. Considering this, I wrote a code for the MDCEV model with RP & SP data. To practice and learn the codes, I have utilized the data from the MDCEV model (without outside good) and RP SP MNL model from Apollo examp...
- 02 Feb 2023, 18:54
- Forum: Errors during model validation and/or estimation.
- Topic: Error in estimating model with Joint RP-SP and HCM
- Replies: 7
- Views: 2724
Re: Error in estimating model with Joint RP-SP and HCM
Thank you Prof. Hess for highlighting this silly mistake on my end. Sincere apologies. I have revised the code and modified the attributes to be used with LVs and utility functions. The results are much better now. I request you to please suggest if the codes are fine now. Please find the attached c...
- 02 Feb 2023, 13:08
- Forum: Errors during model validation and/or estimation.
- Topic: Error in estimating model with Joint RP-SP and HCM
- Replies: 7
- Views: 2724
Re: Error in estimating model with Joint RP-SP and HCM
Okay Sir,
Sorry to bother you again, but it shows ERROR: Singular Hessian, cannot calculate s.e. and after this I am not getting any results for indices (rho square, robust t stat, etc.). Is it the issue with the coding part or the data? How can I resolve it?
Sorry to bother you again, but it shows ERROR: Singular Hessian, cannot calculate s.e. and after this I am not getting any results for indices (rho square, robust t stat, etc.). Is it the issue with the coding part or the data? How can I resolve it?
- 02 Feb 2023, 11:53
- Forum: Errors during model validation and/or estimation.
- Topic: Error in estimating model with Joint RP-SP and HCM
- Replies: 7
- Views: 2724
Re: Error in estimating model with Joint RP-SP and HCM
Thank you Prof. Hess for your swift response. Currently, I am using apollo version 0.2.8. Additionally, I would also like to bring to your notice that I have been working on improving this code and rectifying the problem since the time I requested your help. Based on the FAQ page and Forum queries I...