On Fri, Oct 11, 2013 at 08:49:44PM -0400, [hidden email] wrote:... what a mess!
>
> Most recently, I've been going through the same exercise
> (again for a chapter, now not in a book of my own) for
> "recursion" and "recursive". Again, I have accumulated
Back in the day when I was teaching computational science for a
living, I had to carefully explain the difference between two distinct
meanings of recursion.
1) A "recursive loop" is one whose iterations depend on values computed
in the previous loop. Related obviously to the "oldest" mathematical
definition you gave. It impedes vectorisation and parallelisation of
said loop.
2) A "recursive function" is one that calls itself, a term quite
familiar to people brought up in computer science.
In the good old days, when men programmed in Fortran, concept 1 was
always meant, as Fortran did not support recursion. That has all
changed now :).
And there is a third meaning for recursion used by theoretical
computer scientists, where is basically means a computable
function. See page 29 of Li and Vitanyi's tome of Kolmogorov complexity.
Cheers
-
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Prof Russell Standish Phone 0425 253119 (mobile)
Principal, High Performance Coders
Visiting Professor of Mathematics [hidden email]
University of New South Wales http://www.hpcoders.com.au
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