# FrechetCheck: Checks a Frechet Leash Distance In SimilarityMeasures: Trajectory Similarity Measures

## Description

A function to check whether a Frechet leash distance is successful or not. This is used by the Frechet calculation and does not need to be called directly.

## Usage

 `1` ```FrechetCheck(traj1, traj2, leash, dist1, dist2, distSq12) ```

## Arguments

 `traj1` An m x n matrix containing trajectory1. Here m is the number of points and n is the dimension of the points. `traj2` A k x n matrix containing trajectory2. Here k is the number of points and n is the dimension of the points. The two trajectories are not required to have the same number of points. `leash` A numeric leash value to be checked by the function. `dist1` A vector containing the distance between each successive two points in trajectory1. `dist2` A vector containing the distance between each successive two points in trajectory2. `distSq12` A matrix containing the distance between each pair of two points where 1 point lies in trajectory1 and the other in trajectory2.

## Details

This function is required by `Frechet` and in general does not need to be called directly.

## Value

A boolean value is returned. A value of true is returned if the leash is successful and false if not.

Kevin Toohey

## References

Alt, H. and Godau, M. (1995) Computing the Frechet distance between two polygonal curves. International Journal of Computational Geometry & Applications, 5(01n02), 75–91.

`Frechet`
 ```1 2 3 4 5 6``` ```# Creating two trajectories. path1 <- matrix(c(0, 1, 2, 3, 0, 1, 2, 3), 4) path2 <- matrix(c(0, 1, 2, 3, 4, 5, 6, 7), 4) # Running the Frechet distance algorithm with a test leash of 2. Frechet(path1, path2, 2) ```