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function varargout=dwcirspace(varargin)
%dwcirspace creates a matrix of cyclic or circular spaced points
%
%varargout: (a,[b])
%
%varargint: ([a],[b],[c],[d])
%
% dwcirspace
% construct an 2x101 matrix of 101 circular spaced points with circumcircle centre at [0,0] and circumcircle radius equals to 1.
%
% dwcirspace(n)
% for n=1 an 2x1 vector of a single point is created at y equals to 0 and x equals to 0 plus offset radius 1 based on circumcircle centre at [0,0]. 
% for n=2 an 2x2 matrix of two points for a line is created parallel to x-axis at y equals to 0 and x equals to 0 plus offset radius 1 based on circumcircle centre at [0,0].
% for n>=3 an 2xn+1 matrix of n+1 circular spaced points is created
% construct an 2xn+1 matrix of n+1 circular spaced points with circumcircle centre at [0,0] and circumcircle radius equals to 1.
%
% dwcirspace(n,r)
% construct an 2xn+1 matrix of n+1 circular spaced points with circumcircle centre at [0,0] and circumcircle radius equals to r.
%
% dwcirspace(n,r,x)
% construct an 2xn+1 matrix of n+1 circular spaced points with circumcircle centre at [x,0] and circumcircle radius equals to r.
%
% dwcirspace(n,r,x,y)
% construct an 2xn+1 matrix of n+1 circular spaced points with circumcircle centre at [x,y] and circumcircle radius equals to r.
%
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% Copyright (c) 2014, All Right Reserved, http://sideway.hk/
% LastChanged:20/06/2014
% version:000.00001 created 20/06/2014 from sideway.hk
%
%
if nargin==0
n=100;r=1;x=0;y=0;
elseif nargin==1
n=varargin{1};r=1;x=0;y=0;
elseif nargin==2
n=varargin{1};r=varargin{2};x=0;y=0;
elseif nargin==3
n=varargin{1};r=varargin{2};x=varargin{3};y=0;
elseif nargin==4
n=varargin{1};r=varargin{2};x=varargin{3};y=varargin{4};
else
error('in argument more than four');
end
if n<=0
error('number of point must be greater than zero');
end
th=(0:1/n:1)*2*pi;
xunit=r*cos(th)+x;
yunit=r*sin(th)+y;
if n==1
xunit(2)=[];
yunit(2)=[];
elseif n==2
xunit(3)=[];
yunit(3)=[];
end
if nargout==0
error('out argument less than one');
elseif nargout==1
vrargout{1}=[xunit; yunit];
elseif nargout==2
varargout{1}=xunit;
varargout{2}=yunit;
else
error('out argument more than two');
end