%cart2rad.m
%
% This subroutine takes a series of coordinates in (x,y) and converts them into
% radial coordinates (r,theta) about an origin located at any point in (x,y)-space.
%
function [output] = cart2rad(coordinates,origin)

for i = 1:length(coordinates(:,1))
   output(i,1) = sqrt((coordinates(i,1) - origin(1))^2 + (coordinates(i,1) - origin(2))^2);
   output(i,2) = atan2(coordinates(i,2) - origin(2), coordinates(i,1) -  origin(1));
end