Error in prep_call_sampler(object) : could not find function “prep_call_sampler”

chwzhang09 · June 28, 2019, 2:40pm

Hi,

As the title indicates, when I run the the example (8 schools) code as below, the error regarding prep_call_sampler(object) appears. Please note that before I submitted this ticket, I did a quick check online, for a*b within the model, it has been specified as a * b, and my operation system is Win 10.

Thanks for your input in advance.

bgoodri · June 28, 2019, 5:48pm

The prep_call_sampler function comes with the rstan package

github.com

stan-dev/rstan/blob/develop/rstan/rstan/R/stanmodel-class.R#L86


      mode = mode,
      sim = sim, 
      inits = inits, 
      stan_args = stan_args, 
      stanmodel = stanmodel, 
      date = date(),
      .MISC = miscenv) 
} 




prep_call_sampler <- function(object) {
  if (!is_sm_valid(object))
    stop(paste("the compiled object from C++ code for this model is invalid, possible reasons:\n",
               "  - compiled with save_dso=FALSE;\n", 
               "  - compiled on a different platform;\n", 
               "  - does not exist (created from reading csv files).", sep = '')) 
  if (!is_dso_loaded(object@dso)) {
    # load the dso if available 
    grab_cxxfun(object@dso) 
  } 
}

so there is no way it cannot be found when the rstan package is installed properly.
My guess is that rstan was installed while a previous rstan was loaded or else there were stanfit or stanmodel objects from a previous version of rstan in R’s global environment when you tried to install the new rstan or something else weirdly specific to that laptop. I would suggest closing all R sessions, opening up a new one without bringing in any stanfit or stanmodel objects (including those in the .RData file) and calling

remove.packages("rstan")

then do

install.packages("https://win-builder.r-project.org/jpMlFHwQs41q/rstan_2.19.1.zip", repos = NULL)

again.

chwzhang09 · June 28, 2019, 6:15pm

Hi Ben,

Thank you so much!

Believe or not, I did not delete or remove anything. Just rerun the statement as I did last night at home. It works now…

I am really sick of it…

Ben, thank you so much for your continuous and instant input and help!!!

Chuanwu

alex_d · May 16, 2023, 6:20pm

Hi, I’m having the same issue 'prep_call_sampler(object): could not find function “prep_call_sampler”. I’ve tried uninstalling and reinstalling R, RStudio, rstan, to no avail. it won’t even run the example script. I was running some models last night, woke up today, tried to run the same model, all of a sudden nothing works. Are there any other solutions? Thanks ahead of time!

Running:
R Version 4.3.0 GUI 1.79 Big Sur Intel build
RStudio Version 2023.03.1+446 (2023.03.1+446)
RStan Version 2.21

Oddly, when I use the ‘Ulam’ function from Richard McElreath’s Rethinking package, Stan runs. But it won’t run the example function, or when I use the combo of compiling (stan_model) with sampling().

One more update. When I open a new R project the example stan script works. but not in the one that I am currently using.

Jiamo_Li · June 8, 2024, 7:19pm

Hi, I noticed that you encountered the same issue I’m currently facing. May I ask if you have resolved this problem? I would greatly appreciate it if you could share your solution with me. Thank you very much in advance.

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Error in prep_call_sampler(object) : could not find function “prep_call_sampler”

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