1function c = cond1est (A) 2%COND1EST 1-norm condition estimate. 3% Example: 4% c = cond1est(A) 5% See also: cs_demo 6 7% Copyright 2006-2012, Timothy A. Davis, http://www.suitesparse.com 8 9[m n] = size (A) ; 10if (m ~= n | ~isreal (A)) %#ok 11 error ('A must be square and real') ; 12end 13if isempty(A) 14 c = 0 ; 15 return ; 16end 17[L,U,P,Q] = lu (A) ; 18if (~isempty (find (abs (diag (U)) == 0))) %#ok 19 c = Inf ; 20else 21 c = norm (A,1) * norm1est (L,U,P,Q) ; 22end 23