Hi @kaz-yos,

that list has not been updated as the list refers to the old stan-to-c++ compiler, which is currently still ins use in rstan and pystan.

Cmdstan has switched to stanc3 (as of 2.22), whose signatures can be found here https://github.com/stan-dev/stanc3/blob/master/test/integration/signatures/stan_math_sigs.expected

rstan is expected to switch soon, not sure on the pystan timeline.

But you wont find reduce_sum even in the list I linked as its a variadic function (the first after print()) and those are not listed right now.

These are the supported signatures:

(T[], int, int, …) => real, T[], int, …

(T[,], int, int, …) => real, T[,], int, …

(T[,], int, int, …) => real, T[,], int, …

(T[,], int, int, …) => real, T[,], int, …

(T[,], int, int, …) => real, T[,], int, …

(T[,], int, int, …) => real, T[,], int, …

(T[,], int, int, …) => real, T[,], int, …

Where T is any one of int, real, vector, row_vector or matrix and … can be 0+ arguments of any type (but the “…” arguments must match in types).

If we were to add them in this way would that be useful for you?

(int[], int, int, …) => real, int[], int, …

(int[,], int, int, …) => real, int[,], int, …

(int[,], int, int, …) => real, int[,], int, …

(int[,], int, int, …) => real, int[,], int, …

(int[,], int, int, …) => real, int[,], int, …

(int[,], int, int, …) => real, int[,], int, …

(int[,], int, int, …) => real, int[,], int, …

(real[], int, int, …) => real, real[], int, …

(real[,], int, int, …) => real, real[,], int, …

(real[,], int, int, …) => real, real[,], int, …

(real[,], int, int, …) => real, real[,], int, …

(real[,], int, int, …) => real, real[,], int, …

(real[,], int, int, …) => real, real[,], int, …

(real[,], int, int, …) => real, real[,], int, …

…