# Software Development

## LCS Tool

LCS Tool performs computations for the analysis of Lagrangian coherent structures. It is developed by the Nonlinear Dynamical Systems Group at ETH Zurich, led by Prof. George Haller.

## Demo scripts

MATLAB scripts demonstrating the use of LCS Tool are in the folder named demo. To run these scripts, start MATLAB in the LCS Tool folder, then at the MATLAB prompt type, for example:

cd demo/double_gyre/ addpath ../.. flow_animation

The time required to execute some of the demo scripts is given below. These times were measured on a laptop with an Intel Core i5-3360M processor with 16 gigabytes of memory:

- double_gyre/hyperbolic_shear_lcs: 10 minutes
- bickley_jet/stretchlines: 30 minutes
- ocean_dataset/hyperbolic_shear_lcs_details: 20 minutes

Examples of images produced by these scripts are shown below.

## References

The algorithms used in LCS Tool are based on methods from the following publications:

- G. Haller and F. J. Beron-Vera, "Coherent Lagrangian vortices: the black holes of turbulence".
*Journal of Fluid Mechanics*731 (2013), DOI: 10.1017/jfm.2013.391. - M. M. Farazmand and G. Haller, "Attracting and repelling Lagrangian coherent structures from a single computation",
*Chaos*23 (2013), DOI: 10.1063/1.4800210. - G. Haller and F. J. Beron-Vera, "Geodesic Theory of Transport Barriers in Two-Dimensional Flows",
*Physica D: Nonlinear Phenomena*241 (2012), DOI: 10.1016/j.physd.2012.06.012. - M. M. Farazmand and G. Haller, "Computing Lagrangian coherent structures from their variational theory",
*Chaos*22 (2012), DOI: 10.1063/1.3690153.