Floating Point Almost Equal

v1.0.2

Copyright © 2014, Ryan Porter All rights reserved.

Author: Ryan Porter LAVA Name: Porter Contact Info: Contact Porter via PM on lavag.org

LabVIEW Versions: LV >=8.6 (Windows)

Dependencies: LAVA Palette

Description: This package contains VIs for testing equality of floating point numbers within a specified tolerance. Absolute Epsilon comparison, Relative Epsilon comparison and the ULP comparison have been implemented as described in this blog post by Bruce Dawson: http://randomascii.wordpress.com/2012/02/25/comparing-floating-point-numbers-2012-edition/

Note that the ULP comparison has not been implemented for extended precision floating point type.

Installation and instructions: Install VIP package using VI Package Manager.

Examples: "\examples\LAVA\AlmostEqual\AlmostEqual_Example 1.vi" Demonstrates the usage of all three AlmostEqual functions. "\examples\LAVA\AlmostEqual\AlmostEqual_Example 2.vi" Demonstrates a case where exactly equal fails to produce the expected result.

Known Issues: ULP comparison has not been implemented for extended precision floating point type.

Acknowledgements: Bruce Dawson: Code of this package was inspired by his blog post on comparing floating point numbers (http://randomascii.wordpress.com/2012/02/25/comparing-floating-point-numbers-2012-edition/).

Version History: v1.0.0: Initial release of the code. V1.0.1: Changed icon colors. V1.0.2: Set all VIs to Pre-Allocated Re-Entrant Execution

License: Distributed under the BSD 2-Clause (http://opensource.org/licenses/BSD-2-Clause) See link for a full description of the license.

Support: If you have any problems with this code or want to suggest features contact Porter via PM on lavag.org

Distribution: This code was downloaded from the LAVA Code Repository found at lavag.org

Sources:

1. http://forums.ni.com/t5/LabVIEW/How-to-measure-LSBits-of-difference-between-floats-if-possible/m-p/303665#M158227

2. http://forums.ni.com/t5/LabVIEW-Idea-Exchange/quot-Almost-Equal-quot-functions-for-Float-comparisons/idi-p/1446480

3. http://lavag.org/topic/16733-floating-point-equal-primitive/

4. http://www.cygnus-software.com/papers/comparingfloats/comparingfloats.htm

5. http://randomascii.wordpress.com/2012/02/25/comparing-floating-point-numbers-2012-edition/

6. ftp://ftp.ni.com/pub/devzone/tut/floating_point_in_labview.pdf