ApolloChoiceModelling forum

Dear Profesors,

Thanks for developing such a powerful tool.

I am trying to estimate a MDCEV model. However, I got the following error message:

model = apollo_estimate(apollo_beta, apollo_fixed, apollo_probabilities, apollo_inputs)
Preparing user-defined functions.
Error en if (!test) {: valor ausente donde TRUE/FALSE es necesario

I don't know what's happening. I have used this code before and It has worked perfectly well.

Any help would be very appreciated!

Thanks in advance!

I share the code:

# ################################################################# #
#### LOAD LIBRARY AND DEFINE CORE SETTINGS: SL PORT CHOICE PAPER ####
# ################################################################# #

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

### Load Apollo library
library(apollo)

### Initialise code
apollo_initialise()

### Set core controls
apollo_control = list(
modelName = "MDCEV_SL",
modelDescr = "MDCEV model, alpha-gamma profile, no outside good and constants only in utilities",
indivID = "ID",
outputDirectory = "output"
)

# ################################################################# #
#### LOAD DATA AND APPLY ANY TRANSFORMATIONS ####
# ################################################################# #

### Loading data from package
### if data is to be loaded from a file (e.g. called data.csv),
### the code would be: database = read.csv("data.csv",header=TRUE)
database = read.csv("vb.csv",header=TRUE, sep=";")


### Use only SP data
###database = subset(database,database$SP==1)

# ################################################################# #
#### DEFINE MODEL PARAMETERS ####
# ################################################################# #

### Vector of parameters, including any that are kept fixed in estimation
apollo_beta = c(alpha_base = 0,
gamma_barcelona = 1,
gamma_valencia = 1,
delta_valencia = 0,
b_cost = 0,
b_productivity = 0,
b_hinterland = 0,
b_infras = 0,
sig = 1)



### Vector with names (in quotes) of parameters to be kept fixed at their starting value in apollo_beta, use apollo_beta_fixed = c() if none
apollo_fixed = c("sig", "alpha_base")

# ################################################################# #
#### GROUP AND VALIDATE INPUTS ####
# ################################################################# #

apollo_inputs = apollo_validateInputs()

# ################################################################# #
#### DEFINE MODEL AND LIKELIHOOD FUNCTION ####
# ################################################################# #

apollo_probabilities=function(apollo_beta, apollo_inputs, functionality="estimate"){

### Attach inputs and detach after function exit
apollo_attach(apollo_beta, apollo_inputs)
on.exit(apollo_detach(apollo_beta, apollo_inputs))

### Create list of probabilities P
P = list()

### Define individual alternatives
alternatives = c("barcelona",
"valencia")

### Define availabilities
avail = list(barcelona = 1,
valencia = 1)

### Define continuous consumption for individual alternatives
continuousChoice = list(barcelona = barcelona,
valencia = valencia)

### Define utilities for individual alternatives
V = list()
V[["barcelona" ]] = b_cost * costbcn + b_infras * blbcn + b_productivity * prodbcn + b_hinterland * hintbcn
V[["valencia" ]] = delta_valencia + b_cost * costvlc + b_infras * blvlc + b_productivity * prodvlc + b_hinterland * hintvlc


### Define alpha parameters
alpha = list(barcelona = 1 /(1 + exp(-alpha_base)),
valencia = 1 /(1 + exp(-alpha_base)))

### Define gamma parameters
gamma = list(barcelona = gamma_barcelona,
valencia = gamma_valencia)

### Define costs for individual alternatives
cost = list(barcelona = 1,
valencia = 1)

### Define settings for MDCEV model
mdcev_settings <- list(alternatives = alternatives,
avail = avail,
continuousChoice = continuousChoice,
utilities = V,
alpha = alpha,
gamma = gamma,
sigma = sig,
cost = cost,
budget = 1)

### Compute probabilities using MDCEV model
P[["model"]] = apollo_mdcev(mdcev_settings, functionality)

### Take product across observation for same individual
P = apollo_panelProd(P, apollo_inputs, functionality)

### Prepare and return outputs of function
P = apollo_prepareProb(P, apollo_inputs, functionality)
return(P)
}

# ################################################################# #
#### MODEL ESTIMATION ####
# ################################################################# #

model = apollo_estimate(apollo_beta, apollo_fixed, apollo_probabilities, apollo_inputs)


# ################################################################# #
#### MODEL OUTPUTS ####
# ################################################################# #

# ----------------------------------------------------------------- #
#---- FORMATTED OUTPUT (TO SCREEN) ----
# ----------------------------------------------------------------- #

apollo_modelOutput(model)

# ----------------------------------------------------------------- #
#---- FORMATTED OUTPUT (TO FILE, using model name) ----
# ----------------------------------------------------------------- #

apollo_saveOutput(model)

Hi

apologies for the slow reply. Can you confirm you are using the latest version of Apollo? If the error persists, please send me the code and data and I'll have a look for you

Best wishes

Stephane