Map_rect in the Stan language (MPI is coming)

Suppose I have a parameter which is a vector of size N ( vector X[N] ), I need to map a function on each element in the vector. According to the map_rect example in the manual (example), vector[] thetas are the job specific parameters.

But, in order use this argument to pass the vector X, there is a mismatch in dimension. Is there a way to convert vector X[N] to vector[1] X[N] so that it can be passed into map_rect() as argument?

Just write a for loop for that. So, no, there is not such a function off the shelf,m.