promote int[] to real[] as argument for every function

[bob-carpenter]

Make sure that all functions and distributions specifying real[] arguments also accept int[] arguments.

This should only be done where there is not a specialization for integers. mean(), for example, only has the signature (rea[]):real, and the promotion would allow signature (int[]):real --- the result is the same type because means of integers can be real. Similarly for the Dirichlet density dirichlet_log of signature (real[], real[]): real, which would accept int[] arguments (though only the size-1 int[] argument is an appropriate simplex for the first argument).

• Create a list of functions by scanning the manual index (I'm looking at stan-functions-2.13.0.txt)
  • cov_exp_quad;(real[] x, real sigma, real l);matrix;438
  • cov_exp_quad;(real[] x1, real[] x2 real sigma, real l);matrix;438
  • cumulative_sum;(real[] x);real[];437
  • integrate_ode;(function ode, real[] initial_state, real initial_time, real[] times, real[] theta, real[] x_r, int[] x_i);real[\nobreakspace ,\nobreakspace ];450
  • integrate_ode_bdf;(function ode, real[] initial_state, real initial_time, real[] times, real[] theta, real[] x_r, int[] x_i);real[];450
  • integrate_ode_bdf;(function ode, real[] initial_state, real initial_time, real[] times, real[] theta, real[] x_r, int[] x_i, real rel_tol, real abs_tol, int max_num_steps);real[];450
  • integrate_ode_rk45;(function ode, real[] initial_state, real initial_time, real[] times, real[] theta, real[] x_r, int[] x_i);real[\nobreakspace ,\nobreakspace ];450
  • integrate_ode_rk45;(function ode, real[] initial_state, real initial_time, real[] times, real[] theta, real[] x_r, int[] x_i, real rel_tol, real abs_tol, int max_num_steps);real[\nobreakspace ,\nobreakspace ];450
• doc each new signature
• test each new signature on its own and with an example model instantiating it (mostly in transformed data other than for rngs)

[syclik]

I just updated the issue. We don't have too many functions to tackle.

[WardBrian]

Closed by stan-dev/stanc3#1004