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function [a,b] = cs_esep (A)
%CS_ESEP find an edge separator of a symmetric matrix A
% [a,b] = cs_esep(A) finds a edge separator s that splits the graph of A
% into two parts a and b of roughly equal size. The edge separator is the
% set of entries in A(a,b).
%
% Example:
% Prob = ssget ('HB/bcsstk01') ; A = Prob.A ;
% [a,b] = cs_esep (A) ;
% cspy (A (a,b)) ;
%
% See also CS_NSEP, CS_SEP, CS_ND, SYMRCM.
% CXSparse, Copyright (c) 2006-2022, Timothy A. Davis. All Rights Reserved.
% SPDX-License-Identifier: LGPL-2.1+
if (~isreal (A))
A = spones (A) ;
end
p = symrcm (A) ;
n2 = fix (size(A,1)/2) ;
a = p (1:n2) ;
b = p (n2+1:end) ;
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