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Commented Unassigned: get_One for Complex and Complex32 [5728]

cdrnet — Sun, 07 Apr 2013 18:17:57 GMT

I'm not sure if it's proper issue but in Visual F#, the usual pown function (with integer argument) requires its first argument to have get_One. Complex and Complex32 type have one instead of get_One and thus I can't use pown. Obviously, System.Numerics.Complex has the property One (and hence get_One.) It would be nice if we have get_One for compatibility.

Alternatively, you could provide Complex.pown and Complex32.pown as in BigNumber. I can use float version of pow function, but it simply doesn't feel right for me to use it for small powers like squares or cubes.
Comments: Interesting. Our Complex types implement One exactly like System.Numerics.Complex: as a public static readonly field (and thus technically not a member). However, from what you describe it seems as if F# core extends the Complex type with a One property. If so, we can do exactly the same thing in our F# package. For reference: `pown : ^T -> int -> ^T (requires ^T with static member One and ^T with static member op_Multiply and ^T with static member (/))`

Created Unassigned: get_One for Complex and Complex32 [5728]

seminumber — Sun, 07 Apr 2013 10:46:22 GMT

Closed Issue: Percentile class bug [5702]

cdrnet — Sat, 06 Apr 2013 04:36:56 GMT

In the Percentile class compute Method has bug :

/// <summary>
/// Computes the percentile.
/// </summary>
/// <param name="percentile">The percentile, must be between 0.0 and 1.0 (inclusive).</param>
/// <returns>the requested percentile.</returns>
public double Compute(double percentile)
{
if (percentile < 0 || percentile > 100)
{
throw new ArgumentException("Percentile value must be between 0 and 100.");
}

1.

if (percentile < 0 || percentile > 100) this check must be like :

if (percentile < 0 || percentile > 1)

2.
throw new ArgumentException("Percentile value must be between 0 and 100.");

throw new ArgumentException("Percentile value must be between 0 and 1.");

Closed Issue: True computation of online statistics [5686]

cdrnet — Sat, 06 Apr 2013 04:36:36 GMT

Great thank you,

In my project I used these references: maybe they will help

http://lingpipe-blog.com/2009/07/07/welford-s-algorithm-delete-online-mean-variance-deviation/

http://www.johndcook.com/standard_deviation.html

Best,

JB

Closed Issue: Interpolation data limits? [5725]

cdrnet — Sat, 06 Apr 2013 04:35:28 GMT

Closed Issue: Percentile Failing [5727]

cdrnet — Sat, 06 Apr 2013 04:27:49 GMT

I am getting an Index was out of range error when I try and call Percentile.Compute.

Here is my code :

```
IEnumerable<double> values =new[]{1.1, 2.2, 3.3, 4.4};
Percentile p = new Percentile(values);
p.Method=PercentileMethod.Interpolation;
return (decimal) p.Compute(0.1);

```

Any clues as to what the error could be?

full error info :

```
Index was out of range. Must be non-negative and less than the size of the collection.
```
Comments: Fixed in mainline, thanks!

Closed Issue: (minor) Documentation fix [5724]

cdrnet — Sat, 06 Apr 2013 04:25:22 GMT

Hi,

On http://numerics.mathdotnet.com/api/MathNet.Numerics.Integration/Integrate.htm , the method descriptions (both) say :
Approximation of the definite interval of an analytic smooth function on a closed interval.

I suggest the description be changed to :
Approximation of the definite integral of an analytic smooth function on a closed interval.

... just a suggestion,
Chuck
Comments: Fixed in mainline, thanks!

Commented Issue: Percentile Failing [5727]

RichLinnell — Fri, 05 Apr 2013 08:02:18 GMT

Commented Issue: Percentile Failing [5727]

cdrnet — Thu, 04 Apr 2013 17:05:37 GMT

Commented Issue: Percentile Failing [5727]

cdrnet — Thu, 04 Apr 2013 17:03:20 GMT

Commented Issue: 2D FFT [5726]

cdrnet — Thu, 04 Apr 2013 16:58:40 GMT

Would like fast 2D FFT and the MATLAB equivalent of FFTSHIFT and IFFTSHIFT

John Fraschilla
Comments: You may want to vote for it on [UserVoice](http://feedback.mathdotnet.com/forums/2060-math-net-numerics), here it will get lost. Thanks, Christoph

Created Issue: Percentile Failing [5727]

RichLinnell — Thu, 04 Apr 2013 16:38:17 GMT

Created Issue: 2D FFT [5726]

jfraschilla — Thu, 04 Apr 2013 14:40:03 GMT

Would like fast 2D FFT and the MATLAB equivalent of FFTSHIFT and IFFTSHIFT

John Fraschilla

Commented Issue: Algorithms.LinearAlgebra.Acml disappeared [5720]

mobssoft — Mon, 25 Mar 2013 18:00:25 GMT

Algorithms.LinearAlgebra.Acml namesapace as well as several others - apart from MKL have disappeared in the latest version.
This means that native wrapper tests no longer build.
In general I must say that it is horrendously complicated to enable any non-managed BLAS engine.
It would be really nice if default download included at least one non-managed BLAS implementation - e.g. the reference one. As it stands, one has to spend huge amount of time obtaining pieces of software from various sources.
It also means that default (managed) implementation is several factors of magnitude slower than Matlab, R or the like when it comes to manipulating sizeable matrices.
Comments: Can you restore the ACML for 64-bit only?

Commented Issue: Interpolation data limits? [5725]

cdrnet — Tue, 05 Mar 2013 00:06:50 GMT

Commented Issue: Interpolation data limits? [5725]

cdrnet — Mon, 04 Mar 2013 23:58:26 GMT

I'm using the following method:

IInterpolation ii = MathNet.Numerics.Interpolation.Interpolate.RationalWithoutPoles(points, values);

It seems to work when I'm passing in lists that are less than about 700 items, but fails when I'm using lists that are greater than about 800 items. I'm trying to interpolate an elevation when given a volume.

The attached text file has the raw data (861 items) Ignore the first two columns. The third is the elevation and forth is the volume. When using this data I'm getting either negative values or values that exceed the maximum elevation in the set. If I reduce the same set, by not including the first 200 items, it provides what appears to be a reasonable answer.

Thanks
Comments: Some more notes, related more to your problem than the reported issue itself: Note that an interpolation to a rational function of order >800 is somewhat brutal (school-book approaches like a neville polynomial would utterly fail here, even more as the samples are equidistant); you may want to consider a spline interpolation instead: ``` var ii = new CubicSplineInterpolation(x,y); ``` Looking at the actual curve it seems a rational curve of order 3-4 should represent the data quite well. Do you really need an interpolation, or would a regression (see http://christoph.ruegg.name/blog/2012/9/9/linear-regression-mathnet-numerics.html) e.g. to a polynomial function of order 3-6 do the job as well? Alternatively, interpolating over a small subset of e.g. 5 samples (of the provided 800) could work as well, e.g. like this: ``` var n = 5; var chebyshevNodes = Enumerable.Range(1,n) .Select(i => Math.Cos((2*i-1)*Math.PI/(2*n))) .Select(z => (int)Math.Round((z+1)*(x.Length-1)/2)) .Concat(new[] {0,x.Length-1}) .OrderBy(k => k); var ii = Interpolate.RationalWithoutPoles( chebyshevNodes.Select(k => x[k]).ToArray(), chebyshevNodes.Select(k => y[k]).ToArray()); ```

Commented Issue: Interpolation data limits? [5725]

cdrnet — Mon, 04 Mar 2013 23:55:17 GMT

I'm using the following method:

IInterpolation ii = MathNet.Numerics.Interpolation.Interpolate.RationalWithoutPoles(points, values);

It seems to work when I'm passing in lists that are less than about 700 items, but fails when I'm using lists that are greater than about 800 items. I'm trying to interpolate an elevation when given a volume.

The attached text file has the raw data (861 items) Ignore the first two columns. The third is the elevation and forth is the volume. When using this data I'm getting either negative values or values that exceed the maximum elevation in the set. If I reduce the same set, by not including the first 200 items, it provides what appears to be a reasonable answer.

Thanks
Comments: Thanks. I just had a go at the data provided, but it seems to work fine for me. I used the following snippet, in LinqPad (hence the .Dump calls): ``` var samples = File.ReadAllLines(@"E:\Downloads\elev2vol.txt") .Select(l => l.Split(',').Skip(2).Select(s => Double.Parse(s.Trim())).ToArray()) .ToArray(); var x = samples.Select(z => z[0]).ToArray(); var y = samples.Select(z => z[1]).ToArray(); x.Length.Dump(); var ii = Interpolate.RationalWithoutPoles(x,y); double e1 = 0, e2 = 0, e3 = 0; int count = 0; for(int i=0;i<x.Length-1;i++) { count++; e1 += Math.Abs(ii.Interpolate(x[i]) - y[i]); e2 += Math.Abs(ii.Interpolate((x[i]+x[i+1])/2) - (y[i]+y[i+1])/2); e3 += Math.Abs(ii.Interpolate((4.0*x[i]+x[i+1])/5) - (4.0*y[i]+y[i+1])/5); } (e1 / count).Dump(); (e2 / count).Dump(); (e3 / count).Dump(); ``` returning: 861 (# samples) 0 (mean abs error at sample points, zero expected since this is an interpolation) 0.253021407617856 (mean abs error at center between samples, if it were linear between points) 0.156471265231335 (mean abs error at 1/5 between samples, if it were linear between points) Could you provide some concrete example values where the interpolation fails?

Created Issue: Interpolation data limits? [5725]

dvanwest — Mon, 04 Mar 2013 21:18:53 GMT

Created Issue: (minor) Documentation fix [5724]

chuckmoore55 — Tue, 26 Feb 2013 18:10:36 GMT

Closed Issue: Control.ParallelizeOperation BUG [5723]

cdrnet — Fri, 22 Feb 2013 17:44:04 GMT

There is a potential bug in the method:

`MathNet.Numerics.Control.ParallelizeOperation(int elements)`

This method should return true if the operation should be parallelized; and false otherwise.
Instead, this method returns the exact opposite of this (see the source code).

I would prefer, if the property `DisableParallelization` was set to false (by default) in the future revisions.
Comments: Fixed, thanks for reporting.