Algorithm (Workflow)

This algorithm is designed to find a right-angle point list between a start and end point from an original point list (PL). It is part of the SG-Library and was created by Tim Lueth in 2017.

Input Parameters

• PL: The original point list, which is a matrix where each row represents a point in 2D space.

Output Results

• NPL: The new point list, which includes right-angle turns between the start and end points.

Algorithm Steps

1. Extract the first point p1 and the last point p2 from the point list PL.
2. Initialize a variable gr with a value of 5, which is used to adjust the points.
3. Check if the x-coordinate of p2 is less than that of p1. If true, swap p1 and p2 and set a switch flag sw to true; otherwise, set sw to false.
4. Calculate the direction vectors e1 and e2 using the helper function domez for the first and last segments of the point list, respectively.
5. Adjust p1 and p2 by adding gr times the direction vectors e1 and e2.
6. Create a new point matrix pm that includes p1, a right-angle turn point, and p2.
7. Construct the new point list NPL by combining the first point of PL, the points in pm, and the last point of PL.
8. Remove any straight-line segments from NPL using the function VLremstraightCVL.
9. If the switch flag sw is true, reverse the order of NPL.
10. If no output is requested, plot the original and new point lists using SGfigure and PLplot.

Helper Function: domez

The domez function calculates a unit direction vector along the axis of the largest component of a given vector A. It finds the index of the maximum absolute value in A, sets that component to 1 (or -1 depending on the sign), and zeros out the other components.