Re: Absolute Value |x - y|
Re: Absolute Value |x - y|
- Subject: Re: Absolute Value |x - y|
- From: Shaun Wexler <email@hidden>
- Date: Sun, 5 Dec 2004 11:49:00 -0800
On Dec 5, 2004, at 6:17 AM, R. Scott Thompson wrote:
On Dec 5, 2004, at 12:08 AM, Nicko van Someren wrote:
On 4 Dec 2004, at 19:16, Malte wrote:
i've been looking around trying to find a method that calculates the
|absolute value| of a number.
Without success.
Does anyone know if such a function exists?
This is really a C programming task (and a trivial one at that)
rather than a Cocoa problem.
For the specific case of |x-y| that you give in your subject line you
can use:
absoluteValue = (x>y) ? x-y : y-x;
I'll leave it as an exercise to the reader to work out how to deal
with more general cases.
For floating point numbers there is also fabsf and fabs both declared
in math.h.
That would be one instruction cheaper:
float xMinusY = x - y;
float absXMinusY = __fabs(xMinusY);
vs. the (optimized) macro form:
float xMinusY = x - y;
float yMinusX = y - x;
float absXMinusY = __fsel(xMinusY, xMinusY, yMinusX);
--
Shaun Wexler
MacFOH
http://www.macfoh.com
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