>> help check_tolerances
 
   This function is an auxiliary routine that extracts from the structure "tol"
   various tolerances, flags, and norm estimates used to check for deflation
   and breakdown.  It also checks if the deflation and breakdown tolerances are
   in the range
 
       (2^(-52) = ) eps <= tolerance < 1      (eps = machine precision)
 
   and displays warnings in case they are not.  This auxiliary routine is
   called in the functions "band_Arnoldi", "band_Lanczos", "sym_band_Lanczos",
   "Herm_band_Lanczos", "Jsym_band_Lanczos", and "JHerm_band_Lanczos".
 
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   BANDITS: a Matlab Package of Band Krylov Subspace Iterations
 
   Copyright (c) 2018-2019 Roland W. Freund
   See LICENSE.txt for license
 
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