You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: truncate.m
    path of file: ./repos/chebfun/@chebop2
    
    the code of the file until where you have to start completion: function a = truncate(a, tol)
%TRUNCATE   Truncation of CHEBOP2 objects.
%   A = TRUNCATE(A, TOL) truncates off all elements in A which are below absolute
% value TOL.

% Copyright 2017 by The University of Oxford and The Chebfun Developers.
% See http://www.chebfun.org/ for Chebfun information.

% Fast binary search.
factor = 2;


    
function a = truncate(a, tol)
%TRUNCATE   Truncation of CHEBOP2 objects.
%   A = TRUNCATE(A, TOL) truncates off all elements in A which are below absolute
% value TOL.

% Copyright 2017 by The University of Oxford and The Chebfun Developers.
% See http://www.chebfun.org/ for Chebfun information.

% Fast binary search.
factor = 2;

while ( 1 )
    cut = floor(length(a)*(1-1/factor));
    if ( cut < 1 || length(a) <= 1 )
        break
    end