I've quite frequently seen "codes" meaning "bits of code" in the context of numerical analysis. I think Reuters is talking like an academic scientist rather than like a warez kid.

(It makes me cringe too, though.)

Codes is the normal term in serious numerical computing. Fluid dynamics, finite element, etc people say this all the time.

Isn't this the British English version of code? I think I've seen it elsewhere in British press.