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. This may take a day or two at busy times. There is no need to submit the post multiple times.

Search found 10 matches

by malemu588@gmail.com
19 Oct 2023, 13:54
Forum: Errors during model validation and/or estimation.
Topic: Unconditionals
Replies: 11
Views: 118081

Re: Unconditionals

Hi Stephane, Thanks for your time and support in this forum. I see the version I am using is 0.3.0, so not quite sure when you say the error is related to an old version of Apollo. Of course, I will try to update to the newest version (if available) and see if the error can be eliminated. /Mohammed
by malemu588@gmail.com
13 Oct 2023, 15:47
Forum: Errors during model validation and/or estimation.
Topic: Unconditionals
Replies: 11
Views: 118081

Re: Unconditionals

Yes, I am glad to share the code. ### Clear memory rm(list = ls()) ### Load Apollo library library(apollo) ### Initialise code apollo_initialise() ### Set core controls apollo_control = list( modelName = "LC-MXL", modelDescr = "LC-MXL-classes", indivID = "ID", mixing = ...
by malemu588@gmail.com
13 Oct 2023, 10:53
Forum: Errors during model validation and/or estimation.
Topic: Unconditionals
Replies: 11
Views: 118081

Re: Unconditionals

Thanks for your reply Stephane, I am using version 0.3.0.
/Mohammed
by malemu588@gmail.com
11 Oct 2023, 21:12
Forum: Errors during model validation and/or estimation.
Topic: Unconditionals
Replies: 11
Views: 118081

Unconditionals

Dear Stephane, I am encountering some problems when I am trying to derive the unconditional for some parameters after successfully estimating my model (a latent class mixed logit model). apollo_unconditionals(model, apollo_probabilities, apollo_inputs) Error in length(apollo_draws) && is.na(...
by malemu588@gmail.com
09 Mar 2022, 15:02
Forum: Post-estimation analysis/use of results
Topic: delta method to calculate WTP (normal and log-normal parameters)
Replies: 8
Views: 13333

Re: delta method to calculate WTP (normal and log-normal parameters)

Stephane, thanks really for your help. I appreciate it very much, it helps a lot.

Best,
Mohammed
by malemu588@gmail.com
09 Mar 2022, 14:45
Forum: Post-estimation analysis/use of results
Topic: delta method to calculate WTP (normal and log-normal parameters)
Replies: 8
Views: 13333

Re: delta method to calculate WTP (normal and log-normal parameters)

Thank you Stephane. Yes, that is true, there is a SD as WTP is normal. But my question was really how to estimate the WTP in Apollo when you have random parameters in your model. Sorry if I misunderstood something here. As you said, I need to specify a closed form for the mean and sd to use the delt...
by malemu588@gmail.com
09 Mar 2022, 14:10
Forum: Post-estimation analysis/use of results
Topic: delta method to calculate WTP (normal and log-normal parameters)
Replies: 8
Views: 13333

Re: delta method to calculate WTP (normal and log-normal parameters)

Hi Stephane, Thanks indeed for your response. Okay good to know this. Given that my model is specified in preference space where utility is linear in parameters, can't I just take the ratio of the non-price attribute and the price attribute although the non-price parameters are random? In the follow...
by malemu588@gmail.com
07 Mar 2022, 22:09
Forum: Post-estimation analysis/use of results
Topic: delta method to calculate WTP (normal and log-normal parameters)
Replies: 8
Views: 13333

Re: delta method to calculate WTP (normal and log-normal parameters)

Dear David, I have a random parameter logit model with price parameter fixed and other non-price parameters normally distributed. I used the function you provided above to calculate WTP, and things went well. However, it seems to me that I need to also calculate standard errors separately using anot...
by malemu588@gmail.com
04 Mar 2022, 23:35
Forum: Post-estimation analysis/use of results
Topic: Plotting random parameters to visualize preference heterogeneity
Replies: 1
Views: 2903

Plotting random parameters to visualize preference heterogeneity

Dear Stephane, I am currently running a mixed logit model with random parameters. The model runs well but I also want to plot the random parameters to show preference heterogeneity graphically. This is straight forward in the "Mlogit" package but I am having some challenges in doing the sa...
by malemu588@gmail.com
03 Mar 2022, 18:41
Forum: Feature requests
Topic: IIA
Replies: 8
Views: 22057

Re: IIA

Hi Sven, I tried to estimate full and reduced models, and then directly applied the code you provided. It didn't work for me. By the way, are sub.m and full.m model names in your case?

Thanks in advance.
Best,
Mohammed