Different types of reals in documentation and user defined functions?

[avehtari]

@bgoodri

I personally have pretty much stopped using one-dimensional real arrays in favor of using vectors. I used to use them when there was no linear algebra involving them, but it just got too confusing for students when to use one and when to use the other.

I completely agree about confusion. There’s a problem that some functions accept only real, like cov_exp_quad.