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 5 matches

by Padma
29 Jul 2025, 13:13
Forum: Estimation results
Topic: negative rho values
Replies: 1
Views: 35285

negative rho values

Hi

I am trying to do a route choice model. The data is not surveyed data but synthesized. The routes were generated based on directness measure assuming a unit demand. There were a total of 22 routes generated and the generated data were then grouped into 10 alternatives based on the normalized cdf ...
by Padma
04 Mar 2024, 05:51
Forum: Model estimation
Topic: converting the travel times as travel time cost by multiplying with wage rate
Replies: 1
Views: 30892

converting the travel times as travel time cost by multiplying with wage rate

Hi

I am trying to enter the utility function such that I multiply the wage rate with the travel time to get the travel time cost. Do i enter the wage rate as a socioeconomic variable ? if i enter it as a socioeconomic variable such that the utility is of the form
b_t1=cc+b_t*(WR)
V[['car']] = asc ...
by Padma
06 Apr 2023, 12:31
Forum: Errors during model validation and/or estimation.
Topic: output changed after optimisation
Replies: 9
Views: 80425

Re: output changed after optimisation

Hi

Kindly find attached the code

# ####################################################### #
#### 1. Definition of core settings
# ####################################################### #

### Clear memory
rm(list = ls())

### Load libraries
library(apollo)
#> Apollo 0.2.8
#> http://www ...
by Padma
30 Mar 2023, 13:04
Forum: Errors during model validation and/or estimation.
Topic: output changed after optimisation
Replies: 9
Views: 80425

output changed after optimisation

hi
i have got the following output,


The output of 'apollo_probabilities' has changed after the optimisation of the code carried out by Apollo. This indicates a problem, and
the unoptimised and unscaled version will be used instead. Please contact the developers for assistance!

kindly help on the ...
by Padma
16 Mar 2023, 12:12
Forum: Errors during model validation and/or estimation.
Topic: Error in apollo_probabilities(apollo_beta_shifted, apollo_inputs) : object 'v' not found
Replies: 1
Views: 6597

Error in apollo_probabilities(apollo_beta_shifted, apollo_inputs) : object 'v' not found

Hi

Kindly help me with the following error

Error in apollo_probabilities(apollo_beta_shifted, apollo_inputs) :
object 'v' not found


i have specified v in my model. the code is as follows:
# ####################################################### #
#### 1. Definition of core settings ...