>> find the GCD (greatest common divisor) of the smallest and largest numbers in an array

Just for a short comparison, In J the analogous code is </ +. >/

  Where / is for reduce, +. is for the GCD,  the LCM is *. 

 The basic idea of J notation is using some small change to mean the contrary, for example {. for first and {: for last, {. for take and }. for drop (one symbol can be used as a unary or binary operator with different meaning.  So if floor is <. you can guess what will be the symbol for roof. For another example /:~ is for sorting in ascending order and I imagine that you can guess what is the symbol for sorting in descending order.  In a sense, J notation include some semantic meaning, a LLM could use that notation to try to change an algorithm.  So perhaps someone could think about how to expand this idea for LLM to generate new algorithms.

The matrix m, the sum of the rows, and the maximum of the sum of the rows in J (separated by ;)

  m ; (+/ m) ; >./ +/ m
  ┌─────┬───────┬──┐
  │0 1 2│9 12 15│15│
  │3 4 5│       │  │
  │6 7 8│       │  │
  └─────┴───────┴──┘