From: Mathieu Bouchard <matju@...>
Date: 2001-03-20T13:56:07+09:00
Subject: [ruby-talk:12912] Re: Floating point performance & Garbage collection

On Mon, 19 Mar 2001, Jean-Sebastien ROY wrote:
> My first reaction was : Could Ruby store the floats like it stores the 
> integers ?
> I then read a bit of the ruby source code and besides reducing the size 
> of the fixnum intergers, it does not seem possible.

If Fixnums were constrained to the -2**29..(2**29-1) range, it would
be possible to hold 30-bit floats in a reference. However Ruby's standard
Floats are 64-bit (though each held in a 160-bit box), and
single-precision floats (like C's) are 32-bit.

Downsizing to 30-bit using a trick like f(float x);  return
*((unsigned*)&x)>>2;} (or whatever) is still feasible, but it remains that
a ruby Float is assumed to be 64-bit, and unlike for Fixnums, this is a
change in semantics.

> NArray will probably provide the solution to most of my floating point 
> performance needs.

Good idea.

matju