www.gusucode.com > pde 案例源码 matlab代码程序 > pde/circlefunction.m

    function [x,y] = circlefunction(bs,s)
% Create a unit circle centered at (0,0) using four segments.

switch nargin
    case 0
        x = 4; % four edge segments
        return
    case 1
        A = [0,pi/2,pi,3*pi/2; % start parameter values
             pi/2,pi,3*pi/2,2*pi; % end parameter values
             1,1,1,1; % region label to left
             0,0,0,0]; % region label to right
        x = A(:,bs); % return requested columns
        return
    case 2
        x = cos(s);
        y = sin(s);
end