🚀 go-pugleaf

Jeff Tomich <jtomich@IntNet.net> wrote:
|> Having a hard time to figure out a function on how to compare doubles. 
|> Any ideas?

I'd go along with what the c.l.c. FAQ has to say about this one:

14.5:	What's a good way to check for "close enough" floating-point
	equality?

A:	Since the absolute accuracy of floating point values varies, by
	definition, with their magnitude, the best way of comparing two
	floating point values is to use an accuracy threshold which is
	relative to the magnitude of the numbers being compared.  Rather
	than

		double a, b;
		...
		if(a == b)	/* WRONG */

	use something like

		#include <math.h>

		if(fabs(a - b) <= epsilon * a)

	for some suitably-chosen epsilon.

	References: Knuth Sec. 4.2.2 pp. 217-8.
-- 
"If it wasn't for C, we would be using BASI, PASAL, and OBOL."

Jonas J. Schlein  (schlein@gl.umbc.edu)