Is there a way to pass a 0-length vector as data in RStan?

[Daniel Lee]

I'm thinking of something like...

data {

  int N;

  real y[N];

}
...

and I want to pass from R

data <- list()

data$N <- 0

data$y <- numeric(0)

or something else for data$y that can be passed rstan.

[Ben Goodrich]

That is known to work, but you might need 2.7.0.

Ben
 

[Jonah]

numeric(0) should work actually. For instance this should run:

stancode <- "

 data {

   int N;

   real y[N];

}

 parameters {

   real x;

 }

 model{

   x ~ normal(0,1);

 }

"

fit <- stan(model_code = stancode, data = list(N = 0, y = numeric(0)), chains = 1, iter = 10)

On Saturday, July 18, 2015 at 12:17:04 PM UTC-4, Daniel Lee wrote:

[Jonah]

y could also be logical(0) or integer(0) and it should work too. 

[Daniel Lee]

Ok, I'll try it. I actually had a problem with an int array, but hopefully this works.

Daniel

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[Daniel Lee]

thanks!

[Sebastian Weber]

Hi!

Does this work in cmdstan?

Best,

Sebastian

[Bob Carpenter]

Yes --- you just need to supply a zero-length data vector, c().

- Bob