Comments on: Math Library compatible with full .NET

By: Valkyrie-MT

Valkyrie-MT — Wed, 05 Jan 2011 04:06:41 +0000

Hi Elze,

First – Thank you for this exMath.cs code!
But, I think you may have a small bug in your log function. Apparently double.Epsilon should not be used for comparisons like that. You should use 2.22045e-16 instead. See the thread here: http://forums.netduino.com/index.php?/topic/972-whats-going-on-with-the-operator/page__gopid__7052

By: Peter

Peter — Sat, 18 Dec 2010 01:40:06 +0000

I have been trying to use your Log function but that does not seem to be working. It seems to get to the last while and just goes into a infinite loop.

Any ideas?

By: Skewworks

Skewworks — Mon, 25 Oct 2010 03:56:55 +0000

Your definition for PI is incorrect; it messes with distance calculations; should be 3.1415926535897931

There also seems to be a problem in your atanx method that causes issues as well. I’ll let you know when we’ve narrowed it down and found the solution.

By: Chris Seto

Chris Seto — Fri, 22 Oct 2010 07:34:03 +0000

Hi Elze,

I believe I found a critical error in your library, you didn’t define PI correctly!

Line 45 should be:
public static readonly double PI = 3.1415926535897931F;

By: Kamal

Kamal — Thu, 19 Aug 2010 16:18:59 +0000

Hi, just wanted to write and say THANKS! for making the math library code available. I needed arctan for a project that is helping me learn the Netduino and your code worked beautifully.

By: Wintonlin

Wintonlin — Thu, 21 Jan 2010 12:44:28 +0000

Dear Elze:

Does your math class can be used to do the FFT or some DSP?
Or do you know where can I find the FFT code for .net MF?
Thank you very much

Lin

By: Elze

Elze — Sat, 17 Oct 2009 10:07:44 +0000

Hi Chris,

Thanks I will look into it. If so I will update the class.

Kind regards,

Elze

By: Chris

Chris — Sun, 11 Oct 2009 16:27:13 +0000

Hi Elze,

thanks a lot for your code. But I found that the Atan2() method is buggy. To me it looks like the x and y parameters are swapped.

Could you pls. verify that?

Thanks,
Chris

By: Elze

Elze — Sun, 18 Jan 2009 14:00:00 +0000

Ofcourse,

The Sin, Cos, Tan functions found on:
http://www.ganssle.com/approx/approx.pdf

The Log, Log10 on:
http://en.literateprograms.org/Logarithm_Function_%28Python%29

Information about IEEE754 Floating point:
http://www.radiks.net/~rhuebner/mathlib.html

The rest is written by looking at the BSD Unix source and Wikipedia

By: sanny

sanny — Sun, 18 Jan 2009 13:30:27 +0000

could you provide the location where you find the calculations (implementation)

found something on http://www.koders.com/c/fid668AA602507232FB9BF8DF177A26CC8976024E3F.aspx?s=zreturn or http://forum.unidev.com.br/phpbb2/viewtopic.php?t=43347

thx for help