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    Metadata details:
    filename: chebtech2.m
    path of file: ./repos/chebfun/@chebtech2
    
    the code of the file until where you have to start completion: classdef chebtech2 < chebtech
%CHEBTECH2   Approximate smooth functions on [-1,1] with Chebyshev interpolants.
%
%   Class for approximating smooth functions on the interval [-1,1] using
%   function values at 2nd-kind Chebyshev points and coefficients of the
%   corresponding 1st-kind Chebyshev series expansion.
%
% Constructor inputs:
%   CHEBTECH2(OP) constructs a CHEBTECH2 object from the function handle OP. OP
%   should be vectorised (i.e., accept a vector input) and ouput a vector of
%   the same length. 
    
function values at 2nd-kind Chebyshev points and coefficients of the
%   corresponding 1st-kind Chebyshev series expansion.
%
% Constructor inputs:
%   CHEBTECH2(OP) constructs a CHEBTECH2 object from the function handle OP. OP
%   should be vectorised (i.e., accept a vector input) and ouput a vector of
%   the same length. CHEBTECH2 objects allow for array-valued construction
%   (i.e., of an array-valued function), in which case OP should accept a column
%   vector of length N and return a matrix of size NxM.
%
%   CHEBTECH2(OP, DATA) constructs a CHEBTECH2 using the additional data
%   supplied in the DATA structure.  Fields currently recognized are:
%     DATA.VSCALE    (Default:  0)
%     DATA.HSCALE    (Default:  1)
%         The constructor builds a CHEBTECH2 with 'happiness' (see
%         HAPPINESSCHECK.m) relative to the maximum of the given vertical scale
%         DATA.VSCALE and the (column-wise) infinity norm of the sampled
%         function values of OP, and the fixed horizontal scale DATA.HSCALE. If
%         not given (or given as empty), the VSCALE defaults to 0 initially,
%         and HSCALE defaults to 1.
%   If any fields in DATA are empty or not supplied, or if DATA itself is empty
%   or not supplied, appropriate default values are set.
%
%   CHEBTECH2(OP, DATA, PREF) overrides the default behavior with that given by
%   the preference structure PREF. See CHEBTECH.TECHPREF for details.
%
%   CHEBTECH2(VALUES, ...) returns a CHEBTECH2 object which interpolates the
%   values in the columns of VALUES at 2nd-kind Chebyshev points and
%   CHEBTECH2({VALUES, COEFFS}, ... ) uses the Chebyshev coefficients passed in
%   COEFFS rather than computing them from VALUES. If VALUES, is empty then the
%   CHEBTECH2 is constructed directly from the COEFFS. If COEFFS are passed,
%   the resulting CHEBTECH2 is always deemed 'happy'.
%
% Examples: % Basic construction: f = chebtech2(@(x) sin(x))
%
%   % Construction with preferences:
%   p.sampleTest = 0; % See CHEBTECH.TECHPREF for details
%   f = chebtech2(@(x) sin(x), [], [], p)
%
%   % Array-valued construction:
%   f = chebtech2(@(x) [sin(x), cos(x), exp(x)])
%
% See also CHEBTECH, CHEBTECH.TECHPREF, CHEBPTS, HAPPINESSCHECK, REFINE.

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

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% CHEBTECH2 Class Description:
%
% The CHEBTECH2 class represents smooth functions on the interval [-1,1] using
% function values at 2nd-kind Chebyshev points and coefficients of the
% corresponding 1st-kind Chebyshev series expansion.
%
% The constructor is supplied with a handle that evaluates a given function on
% an increasingly fine Chebyshev 2nd-kind grid (see REFINE.m) until the
% representation is deemed 'happy' (see HAPPINESSCHECK.m). The resulting object
% can be used to evaluate and operate on the input function.
%
% More information can be found in the CHEBTECH class definition.
%
% Class diagram: [<<CHEBTECH>>] <-- [CHEBTECH2]
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    
    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    %% CLASS CONSTRUCTOR:
    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    methods ( Access = public, Static = false )
        
        function obj = chebtech2(op, data, pref)
            % Parse inputs.
            if ( (nargin == 0) || isempty(op) )
                % Return an empty CHEBTECH2 on null input:
                return
            end