# TISEAN package

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## Porting TISEAN

This section will focus on demonstrating the capabilities of the TISEAN package. The previous information about the porting procedure has been moved here.

## Tutorials

These tutorials are based on examples, tutorials and the articles located on the TISEAN website:
http://www.mpipks-dresden.mpg.de/~tisean/Tisean_3.0.1/.
This tutorial will utilize the following dataset:

Please download it as the tutorial will reference it.

### Noise Reduction

This tutorial show different methods of the 'Noise Reduction' section of the TISEAN documentation (located here). It shows the use of simple nonlinear noise reduction (function `lazy`) and locally projective nonlinear noise reduction (function `ghkss`). To start let's create noisy data to work with.

 Code: Creating a noisy henon map ```hen = henon (10000); hen = hen(:,1); # We only need the first column hen_noisy = hen + std (hen) * 0.02 .* (-6 + sum (rand ([size(hen), 12]), 3)); ```

This created a Henon map contaminated by 2% Gaussian noise à la TISEAN. In the tutorials and exercises on the TISEAN website this would be equivalent to calling `makenoise -%2` on the Henon map.
Next we will reduce the noise using simple nonlinear noise reduction `lazy`.

 Code: Simple nonlinear noise reduction ```clean = lazy (hen_noisy,7,-0.06,3); # Create delay vectors for both the clean and noisy data delay_clean = delay (clean); delay_noisy = delay (hen_noisy); # Plot both on one chart plot (delay_noisy(:,1), delay_noisy(:,2), 'b.;Noisy Data;','markersize,3,... delay_clean(:,1), delay_clean(:,2), 'r.;Clean Data;','markersize,3) ```

On the chart created the red dots represent cleaned up data. It is much closer to the original than the noisy set.
Now we will do the same, only with `ghkss`.

 Code: Locally projective nonlinear noise reduction ```clean = ghkss (hen(:,1),'m',7,'q',2,'r',0.05,'k',20,'i',2); # Create delay vectors for both the clean and noisy data delay_clean = delay (clean); delay_noisy = delay (hen_noisy); # Plot both on one chart plot (delay_noisy(:,1), delay_noisy(:,2), 'b.;Noisy Data;','markersize,3,... delay_clean(:,1), delay_clean(:,2), 'r.;Clean Data;','markersize,3) ```