1function s = tol_is_default (tol)
2%TOL_IS_DEFAULT return true if tol is default, false otherwise
3% usage: s = tol_is_default (tol)
4
5% Copyright 2012, Leslie Foster and Timothy A Davis.
6
7s = (isempty (tol) || ischar (tol) || (isreal (tol) && tol < 0)) ;
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