I want to define priors for a k-dimensional array, such as

```
parameters{
array[dim1, dim2, dim3] real param;
}
model {
param ~ beta(3, 3);
}
```

But stan is complaining with an error, I can only define the priors using a loop, for each parameter. I don’t have an issue with defining the loop.

```
parameters{
array[dim1, dim2, dim3] real param;
}
model {
for(i in 1:dim1){
for(j in 1:dim2){
for(k in 1:dim3){
param[i, j, k] ~ beta(3, 3);
}
}
}
}
```

But I am worried that it will make the code much slower since it will need to define dim1*dim2*dim3 priors individually.

Does anyone know if there is a big performance difference? Or if there is an alternative to making a loop?

Thanks :)