Vectorized logical functions

Description

As discussed here, the logical functions don't support vectorization yet.

New functions

Add functions for the logical operators (==,<, <=, >, >=) and their functions (logical_eq, etc.) to allow containers as arguments and support broadcasting. The signatures will be, for example,

int logical_eq(scalar, scalar);
int[] logical_eq(scalars, scalars);
int[] logical_eq(scalar, scalars);
int[] logical_eq(scalars, scalar);

where

• scalar is int | real | complex
• scalars is scalar[] | vector | row_vector | complex_vector | complex_row_vector.

If there are two scalar inputs, the existing function is called. If one of the arguments is a container, the other argument must be a container of the same shape or a scalar. With a scalar and container, the scalar is broadcast.

Vectorized logic

We also want to add two functions

int any(scalars);
int all(scalars);

where the first returns 0 if all of the arguments are 0 and 1 otherwise, and the second returns 0 if any of the arguments is 0 and 1 otherwise. We could also add a not function that performs elementwise negation.

Example & Expected Output

data {
  int N;
  real x1[N];
  real x2[N];
}
transformed data {
  real y = sum(x1 > x2);
}

Current error:

No matches for: logical_gt(real[ ], real[ ])

Current Version:

v4.6.2

Start by reviewing the existing scalar logical operators and functions such as logical_eq, logical_gt, and the related logical-functions documentation, then inspect the discussion in issue 202. Done means container and scalar/container combinations support the stated broadcasting and shape rules, with any and all added as specified and the example no longer producing a no-match error.