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From: James Hague <jhague@dadgum.com>
To: caml-list@inria.fr
Subject: Numeric programming efficiency question
Date: Mon, 22 Mar 1999 12:33:11 -0600 (EST)	[thread overview]
Message-ID: <Pine.LNX.3.96.990322122948.12166A-100000@babba.advancenet.net> (raw)

First of all, let me say that I've been having a great time learning
Objective CAML!

I implemented some simple functions that operate on three dimensional
vectors.  After reading the "Numeric Programming in CAML" document, it
seems that, unfortunately, the code resulting from using a more classic
syntax is less efficient than using structures.  That is, this:

let vadd (x0,y0,z0) (x1,y1,z1) = (x0 +. x1, y0 +. y1, z0 +. z1);;

generates poorer code than:

type vector = {x: float; y: float; z: float};;
let vadd a b = {x = a.x +. b.x; y = a.y +. b.y; z = a.z +. b.z};;

When using this function, one implementation has a more concise calling
syntax:

vadd (1.0,2.0,3.0) (10.0,20.0,30.0);;
vadd {x=1.0;y=2.0;z=3.0} {x=10.0;y.0;z=30.0};;

A utility routine makes the second option a little nicer:

let vec (a,b,c) = {x=a; y=b; z=c};;

This lets one write:

vadd vec(1.0,2.0,3.0) vec(10.0,20.0,30.0);;

I'm curious if the "shape changing" vec routine is optimized away in such
an expression.  I would expect it to be, but that's just the wishful
programmer in me.

James Hague




             reply	other threads:[~1999-03-22 19:00 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
1999-03-22 18:33 James Hague [this message]
1999-03-23 17:12 ` Xavier Leroy
1999-03-23 19:32   ` James Hague

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