% UTP_AO_FIXFS a set of UTPs for the ao/fixfs method
%
% M Hewitson 06-08-08
%
% $Id: utp_ao_fixfs.m,v 1.19 2011/08/22 05:04:49 hewitson Exp $
%

% <MethodDescription>
%
% The fixfs method of the ao class resamples time-series AOs to have a
% fixed sample rate.
%
% </MethodDescription>

function results = utp_ao_fixfs(varargin)

  % Check the inputs
  if nargin == 0

    % Some keywords
    class   = 'ao';
    mthd    = 'fixfs';

    results = [];
    disp('******************************************************');
    disp(['****  Running UTPs for ' class '/' mthd]);
    disp('******************************************************');

    % Test AOs
    [at1,at2,at3,at4,at5,at6,atvec,atmat] = eval(['get_test_objects_' class]);

    % Exception list for the UTPs:
    [ple1,ple2,ple3,ple4,ple5,ple6] = get_test_ples();

    % Run the tests
    results = [results utp_01];    % getInfo call
    results = [results utp_02];    % Vector input
    results = [results utp_03];    % Matrix input
    results = [results utp_04];    % List input
    results = [results utp_05];    % Test with mixed input
    results = [results utp_06];    % Test history is working
    results = [results utp_07];    % Test the modify call works
    results = [results utp_08];    % Test the data shape
    results = [results utp_09];    % Test output of the data
    results = [results utp_10];    % Test multiple 'fs' for multiple input AOs
    
    results = [results utp_11(mthd, at1, ple1)];    % Test plotinfo doesn't disappear    
    
    results = [results utp_12];    % Test with plist: method == 'samples'
    results = [results utp_13];    % Test with antialising filter
    results = [results utp_14];    % Test AO with non evenly sampled data
    
    disp('Done.');
    disp('******************************************************');

  elseif nargin == 1 % Check for UTP functions
    if strcmp(varargin{1}, 'isutp')
      results = 1;
    else
      results = 0;
    end
  else
    error('### Incorrect inputs')
  end

  %% UTP_01

  % <TestDescription>
  %
  % Tests that the getInfo call works for this method.
  %
  % </TestDescription>
  function result = utp_01


    % <SyntaxDescription>
    %
    % Test that the getInfo call works for no sets, all sets, and each set
    % individually.
    %
    % </SyntaxDescription>

    try
      % <SyntaxCode>
      % Call for no sets
      io(1) = eval([class '.getInfo(''' mthd ''', ''None'')']);
      % Call for all sets
      io(2) = eval([class '.getInfo(''' mthd ''')']);
      % Call for each set
      for kk=1:numel(io(2).sets)
        io(kk+2) = eval([class '.getInfo(''' mthd ''', ''' io(2).sets{kk} ''')']);
      end
      % </SyntaxCode>
      stest = true;
    catch err
      disp(err.message)
      stest = false;
    end

    % <AlgoDescription>
    %
    % 1) Check that getInfo call returned an minfo object in all cases.
    % 2) Check that all plists have the correct parameters.
    %
    % </AlgoDescription>

    atest = true;
    if stest
      % <AlgoCode>
      % check we have minfo objects
      if isa(io, 'minfo')
        %%% SET 'None'
        if ~isempty(io(1).sets), atest = false; end
        if ~isempty(io(1).plists), atest = false; end
        %%% Check all Sets
        if ~any(strcmpi(io(2).sets, 'Default')), atest = false; end
        if numel(io(2).plists) ~= numel(io(2).sets), atest = false; end
        %%%%%%%%%%   SET 'Default'
        if io(3).plists.nparams ~= 4, atest = false; end
        % Check key
        if ~io(3).plists.isparam('fs'), atest = false; end
        if ~io(3).plists.isparam('method'), atest = false; end
        if ~io(3).plists.isparam('filter'), atest = false; end
        if ~io(3).plists.isparam('interpolation'), atest = false; end
        % Check default value
        if ~isequal(io(3).plists.find('fs'), -1), atest = false; end
        if ~strcmpi(io(3).plists.find('method'), 'time'), atest = false; end
        if ~isequal(io(3).plists.find('filter'), 'off'), atest = false; end
        if ~isequal(io(3).plists.find('interpolation'), 'spline'), atest = false; end
        % Check options
        if ~isequal(io(3).plists.getOptionsForParam('fs'), {-1}), atest = false; end
        if ~isequal(io(3).plists.getOptionsForParam('method'), {'time', 'samples'}), atest = false; end
        if ~isequal(io(3).plists.getOptionsForParam('interpolation'), {'nearest', 'linear', 'spline', 'cubic'}), atest = false; end
      end
      % </AlgoCode>
    else
      atest = false;
    end

    % Return a result structure
    result = utp_prepare_result(atest, stest, dbstack, mfilename);
  end % END UTP_01

  %% UTP_02

  % <TestDescription>
  %
  % Tests that the fixfs method works with a vector of AOs as input.
  %
  % </TestDescription>
  function result = utp_02

    % <SyntaxDescription>
    %
    % Test that the fixfs method works for a vector of AOs as input.
    %
    % </SyntaxDescription>

    try
      % <SyntaxCode>
      avec = [at1 at5 at6];
      out  = fixfs(avec);
      % </SyntaxCode>
      stest = true;
    catch err
      disp(err.message)
      stest = false;
    end

    % <AlgoDescription>
    %
    % 1) Check that the number of elements in 'out' is the same as
    %    the number in the input.
    % 2) Check that each output AO contains the correct data.
    %
    % </AlgoDescription>

    atest = true;
    if stest
      % <AlgoCode>
      % Check we have the correct number of outputs
      if numel(out) ~= numel(avec), atest = false; end
      % Check the output data
      for kk = 1:numel(avec)
        fs = avec(kk).fs;
        t0 = 0;
        Nsecs = avec(kk).data.nsecs;
        t = t0 + [0:1/fs:Nsecs-1/fs].';
        y = interp1(avec(kk).x,avec(kk).y, t, 'spline', 'extrap');
        if ~isequal(y, out(kk).y), atest = false; end
        if ~isequal(t, out(kk).x), atest = false; end
      end
      % </AlgoCode>
    else
      atest = false;
    end

    % Return a result structure
    result = utp_prepare_result(atest, stest, dbstack, mfilename);
  end % END UTP_02

  %% UTP_03

  % <TestDescription>
  %
  % Tests that the fixfs method works with a matrix of AOs as input.
  %
  % </TestDescription>
  function result = utp_03

    % <SyntaxDescription>
    %
    % Test that the fixfs method works for a matrix of AOs as input.
    %
    % </SyntaxDescription>

    try
      % <SyntaxCode>
      amat = [at1 at5 at6; at5 at6 at1];
      out  = fixfs(amat);
      % </SyntaxCode>
      stest = true;
    catch err
      disp(err.message)
      stest = false;
    end

    % <AlgoDescription>
    %
    % 1) Check that the number of elements in 'out' is the same as
    %    the number in the input.
    % 2) Check that each output AO contains the correct data.
    %
    % </AlgoDescription>

    atest = true;
    if stest
      % <AlgoCode>
      % Check we have the correct number of outputs
      if numel(out) ~= numel(amat), atest = false; end
      % Check the output data
      for kk = 1:numel(amat)
        fs = amat(kk).fs;
        t0 = 0;
        Nsecs = amat(kk).data.nsecs;
        t = t0 + [0:1/fs:Nsecs-1/fs].';
        y = interp1(amat(kk).x,amat(kk).y, t, 'spline', 'extrap');
        if ~isequal(y, out(kk).y), atest = false; end
        if ~isequal(t, out(kk).x), atest = false; end
      end
      % </AlgoCode>
    else
      atest = false;
    end

    % Return a result structure
    result = utp_prepare_result(atest, stest, dbstack, mfilename);
  end % END UTP_03

  %% UTP_04

  % <TestDescription>
  %
  % Tests that the fixfs method works with a list of AOs as input.
  %
  % </TestDescription>
  function result = utp_04

    % <SyntaxDescription>
    %
    % Test that the fixfs method works for a list of AOs as input.
    %
    % </SyntaxDescription>

    try
      % <SyntaxCode>
      out = fixfs(at1,at5,at6);
      % </SyntaxCode>
      stest = true;
    catch err
      disp(err.message)
      stest = false;
    end

    % <AlgoDescription>
    %
    % 1) Check that the number of elements in 'out' is the same as
    %    the number in the input.
    % 2) Check that each output AO contains the correct data.
    %
    % </AlgoDescription>

    atest = true;
    aoin  = [at1, at5, at6];
    if stest
      % <AlgoCode>
      % Check we have the correct number of outputs
      if numel(out) ~= 3, atest = false; end
      % Check the output data
      for kk = 1:numel(aoin)
        fs = aoin(kk).fs;
        t0 = 0;
        Nsecs = aoin(kk).data.nsecs;
        t = t0 + [0:1/fs:Nsecs-1/fs].';
        y = interp1(aoin(kk).x,aoin(kk).y, t, 'spline', 'extrap');
        if ~isequal(y, out(kk).y), atest = false; end
        if ~isequal(t, out(kk).x), atest = false; end
      end
      % </AlgoCode>
    else
      atest = false;
    end

    % Return a result structure
    result = utp_prepare_result(atest, stest, dbstack, mfilename);
  end % END UTP_04

  %% UTP_05

  % <TestDescription>
  %
  % Tests that the fixfs method works with a mix of different shaped AOs as
  % input.
  %
  % </TestDescription>
  function result = utp_05

    % <SyntaxDescription>
    %
    % Test that the fixfs method works with an input of matrices and vectors
    % and single AOs. Additionally define a 'fs' in a plist.
    %
    % </SyntaxDescription>

    try
      % <SyntaxCode>
      fs = 7;
      pl = plist('fs', fs);
      out = fixfs(at1,[at5 at6],at5,[at5 at1; at6 at1],at6, pl);
      % </SyntaxCode>
      stest = true;
    catch err
      disp(err.message)
      stest = false;
    end

    % <AlgoDescription>
    %
    % 1) Check that the number of elements in 'out' is the same as in
    %    input.
    % 2) Check that each output AO contains the correct data.
    % 3) Check that 't0' and 'fs' are correct.
    %
    % </AlgoDescription>

    TOL   = 1e-14;
    atest = true;
    aoin  = [at1, reshape([at5 at6], 1, []), at5, reshape([at5 at1; at6 at1], 1, []), at6];
    if stest
      % <AlgoCode>
      % Check we have the correct number of outputs
      if numel(out) ~= 9, atest = false; end
      % Check the output data
      for kk = 1:numel(aoin)
        Nsecs = aoin(kk).data.nsecs;
        % We have to think about what we want to do with t0
        t0 = aoin(kk).data.t0.double;
        % This is numerically more accurate
        t = [0:1/fs:Nsecs-1/fs].';
        y = interp1(aoin(kk).x, aoin(kk).y, t, 'spline', 'extrap');
        if ~isequal(y, out(kk).y), atest = false; end
        if any(abs(t-out(kk).x)>TOL), atest = false; end
        % Check 't0' and 'fs'
        if ~isequal(out(kk).fs, fs), atest = false; end
        if ~isequal(out(kk).t0.utc_epoch_milli, t0*1000), atest = false; end
      end
      % </AlgoCode>
    else
      atest = false;
    end

    % Return a result structure
    result = utp_prepare_result(atest, stest, dbstack, mfilename);
  end % END UTP_05

  %% UTP_06

  % <TestDescription>
  %
  % Tests that the fixfs method properly applies history.
  %
  % </TestDescription>
  function result = utp_06

    % <SyntaxDescription>
    %
    % Test that the result of applying the fixfs method can be processed back
    % to an m-file. Additionally define a 'fs' in a plist.
    %
    % </SyntaxDescription>

    try
      % <SyntaxCode>
      fs = 7;
      pl = plist('fs', fs);
      out  = fixfs(at5, pl);
      mout = rebuild(out);
      % </SyntaxCode>
      stest = true;
    catch err
      disp(err.message)
      stest = false;
    end

    % <AlgoDescription>
    %
    % 1) Check that the last entry in the history of 'out' corresponds to
    %    'fixfs'.
    % 2) % Check that the re-built object is the same object as 'out'.
    %
    % </AlgoDescription>

    TOL   = 1e-14;
    atest = true;
    if stest
      % <AlgoCode>
      % Check the last step in the history of 'out'
      if ~strcmp(out.hist.methodInfo.mname, 'fixfs'), atest = false; end
      % Check the output data
      Nsecs = at5.data.nsecs;
      % We have to think about what we want to do with t0
      t0 = at5.data.t0.double;
      % This is numerically more accurate
      t = [0:1/fs:Nsecs-1/fs].';
      y = interp1(at5.x, at5.y, t, 'spline', 'extrap');
      if ~isequal(y, out.y), atest = false; end
      if any(abs(t-out.x)>TOL), atest = false; end
      % Check 't0' and 'fs'
      if ~isequal(out.fs, fs), atest = false; end
      if ~isequal(out.t0.utc_epoch_milli, t0*1000), atest = false; end
      % % Check the re-built object
      if ~eq(mout, out, ple2), atest = false; end
      % </AlgoCode>
    else
      atest = false;
    end

    % Return a result structure
    result = utp_prepare_result(atest, stest, dbstack, mfilename);
  end % END UTP_06

  %% UTP_07

  % <TestDescription>
  %
  % Tests that the fixfs method can modify the input AO.
  %
  % </TestDescription>
  function result = utp_07

    % <SyntaxDescription>
    %
    % Test that the fixfs method can modify the input AO by calling
    % with no output.
    %
    % </SyntaxDescription>

    try
      % <SyntaxCode>
      fs   = 27;
      pl   = plist('fs', fs);
      % copy at1 to work with
      ain   = ao(at1);
      % modify ain
      aout   = ain.fixfs(pl);
      ain.fixfs(pl);
      % </SyntaxCode>
      stest = true;
    catch err
      disp(err.message)
      stest = false;
    end

    % <AlgoDescription>
    %
    % 1) Check that 'at1' and 'ain' are now different.
    % 2) Check that 'ain' is fixfs(at1).
    %
    % </AlgoDescription>

    TOL   = 1e-14;
    atest = true;
    if stest
      % <AlgoCode>
      % Check that fixfs modified the input by comparing to the copy
      if eq(ao(at1), ain, ple1), atest = false; end
      % Check that fixfs doesn't modified the input for the function notation
      if ~eq(aout, ain, ple1), atest = false; end
      % Check the output data
      Nsecs = at1.data.nsecs;
      % We have to think about what we want to do with t0
      t0 = at1.data.t0.double;
      % This is numerically more accurate
      t = [0:1/fs:Nsecs-1/fs].';
      y = interp1(at1.x, at1.y, t, 'spline', 'extrap');
      if ~isequal(y, ain.y), atest = false; end
      if any(abs(t-ain.x)>TOL), atest = false; end
      % Check 't0' and 'fs'
      if ~isequal(ain.fs, fs), atest = false; end
      if ~isequal(ain.t0.utc_epoch_milli, t0*1000), atest = false; end
      % </AlgoCode>
    else
      atest = false;
    end

    % Return a result structure
    result = utp_prepare_result(atest, stest, dbstack, mfilename);
  end % END UTP_07

  %% UTP_08

  % <TestDescription>
  %
  % Tests that the fixfs method keeps the data shape of the input object.
  %
  % </TestDescription>
  function result = utp_08

    % <SyntaxDescription>
    %
    % Test that the fixfs method keeps the data shape of the input object. The
    % input AO must be an AO with row data and an AO with column data.
    %
    % </SyntaxDescription>

    try
      % <SyntaxCode>
      fs   = 27;
      pl   = plist('fs', fs);
      out1 = fixfs(at5, pl);
      out2 = fixfs(at6, pl);
      % </SyntaxCode>
      stest = true;
    catch err
      disp(err.message)
      stest = false;
    end

    % <AlgoDescription>
    %
    % 1) Check that the shpe of the data doesn't change.
    %
    % </AlgoDescription>

    atest = true;
    if stest
      % <AlgoCode>
      % Check the shape of the output data
      if size(out1.data.y,2) ~= 1, atest = false; end
      if size(out2.data.y,1) ~= 1, atest = false; end
      % </AlgoCode>
    else
      atest = false;
    end

    % Return a result structure
    result = utp_prepare_result(atest, stest, dbstack, mfilename);
  end % END UTP_08

  %% UTP_09

  % <TestDescription>
  %
  % Check that the fixfs method pass back the output objects to a list of
  % output variables or to a single variable.
  %
  % </TestDescription>
  function result = utp_09

    % <SyntaxDescription>
    %
    % Call the method with a list of output variables and with a single output
    % variable. Additionaly check that the rebuild method works on the output.
    %
    % </SyntaxDescription>

    try
      % <SyntaxCode>
      fs   = 27;
      pl   = plist('fs', fs);
      [o1, o2] = fixfs(at5, at6, pl);
      o3  = fixfs(at5, at6, pl);
      mout1 = rebuild(o1);
      mout2 = rebuild(o2);
      mout3 = rebuild(o3);
      % </SyntaxCode>
      stest = true;
    catch err
      disp(err.message)
      stest = false;
    end

    % <AlgoDescription>
    %
    % 1) Check that the output contains the right number of objects
    % 2) Check that the 'rebuild' method produces the same object as 'out'.
    %
    % </AlgoDescription>

    atest = true;
    if stest
      % <AlgoCode>
      % Check the number of outputs
      if numel(o1) ~=1, atest = false; end
      if numel(o2) ~=1, atest = false; end
      if numel(o3) ~=2, atest = false; end
      % Check the rebuilding of the object
      if ~eq(o1, mout1, ple2), atest = false; end
      if ~eq(o2, mout2, ple2), atest = false; end
      if ~eq(o3, mout3, ple2), atest = false; end
      % </AlgoCode>
    else
      atest = false;
    end

    % Return a result structure
    result = utp_prepare_result(atest, stest, dbstack, mfilename);
  end % END UTP_09

  %% UTP_10

  % <TestDescription>
  %
  % Tests that the fixfs method works with a list of AOs as input and different
  % 't0' and 'fs' for the inputs.
  %
  % </TestDescription>
  function result = utp_10

    % <SyntaxDescription>
    %
    % Test that the fixfs method works for a list of AOs as input and different
    % 't0' and 'fs'
    %
    % </SyntaxDescription>

    try
      % <SyntaxCode>
      fs_in = [ 3 7 9 ];
      pl    = plist('fs', fs_in);
      out   = fixfs(at1,at5,at6, pl);
      % </SyntaxCode>
      stest = true;
    catch err
      disp(err.message)
      stest = false;
    end

    % <AlgoDescription>
    %
    % 1) Check that the number of elements in 'out' is the same as
    %    the number in the input.
    % 2) Check that each output AO contains the correct data.
    % 3) Check that each output contains the correct frequency and start time.
    %
    % </AlgoDescription>

    TOL   = 1e-14;
    atest = true;
    aoin  = [at1, at5, at6];
    if stest
      % <AlgoCode>
      % Check we have the correct number of outputs
      if numel(out) ~= 3, atest = false; end
      % Check the output data
      for kk = 1:numel(aoin)
        fs = fs_in(kk);
        t0 = aoin(kk).data.t0.double;
        Nsecs = aoin(kk).data.nsecs;
        t = [0:1/fs:Nsecs-1/fs].';
        y = interp1(aoin(kk).x,aoin(kk).y, t, 'spline', 'extrap');
        if ~isequal(y, out(kk).y), atest = false; end
        if any(abs(t-out(kk).x)>TOL), atest = false; end
        % Check 't0' and 'fs'
        if abs(out(kk).fs - fs)>TOL, atest = false; end
        if ~isequal(out(kk).t0.utc_epoch_milli, t0*1000), atest = false; end
      end
      % </AlgoCode>
    else
      atest = false;
    end

    % Return a result structure
    result = utp_prepare_result(atest, stest, dbstack, mfilename);
  end % END UTP_10


  %% UTP_12

  % <TestDescription>
  %
  % Tests that the fixfs method works with the method 'samples'.
  %
  % </TestDescription>
  function result = utp_12

    % <SyntaxDescription>
    %
    % Test that the fixfs method works for the method 'samples'.
    %
    % </SyntaxDescription>

    try
      % <SyntaxCode>
      pl  = plist('method', 'Samples');
      out = fixfs(at1, pl);
      % </SyntaxCode>
      stest = true;
    catch err
      disp(err.message)
      stest = false;
    end

    % <AlgoDescription>
    %
    % 1) Check that each output AO contains the correct data.
    % 2) Check that each output contains the correct frequency and start time.
    %
    % </AlgoDescription>

    TOL   = 1e-14;
    atest = true;
    if stest
      % <AlgoCode>
      % Check the output data
      N = length(at1.y);
      t = linspace(0, (N-1)/at1.fs, N).';
      y  = interp1(at1.x,at1.y, t, 'spline', 'extrap');
      if ~isequal(y, out.y), atest = false; end
      if any(abs(t-out.x)>TOL), atest = false; end
      % Check 'fs'
      if ~isequal(out.fs, 1/(t(2)-t(1))), atest = false; end
      % </AlgoCode>
    else
      atest = false;
    end

    % Return a result structure
    result = utp_prepare_result(atest, stest, dbstack, mfilename);
  end % END UTP_12

  %% UTP_13

  % <TestDescription>
  %
  % Tests that the fixfs method works with antialising filter.
  %
  % </TestDescription>
  function result = utp_13

    % <SyntaxDescription>
    %
    % Test that the fixfs method works for the antialising filters iir and fir.
    %
    % </SyntaxDescription>

    try
      % <SyntaxCode>
      pl_iir  = plist('filter', 'iir');
      pl_fir  = plist('filter', 'fir');
      out_iir = fixfs(at1, pl_iir);
      out_fir = fixfs(at1, pl_fir);
      % </SyntaxCode>
      stest = true;
    catch err
      disp(err.message)
      stest = false;
    end

    % <AlgoDescription>
    %
    % 1) Check that each output AO contains the correct data.
    % 2) Check that each output contains the correct frequency and start time.
    %
    % </AlgoDescription>

    TOL   = 1e-14;
    atest = true;
    if stest
      % <AlgoCode>
      % Check the output data
      Nsecs = at1.data.nsecs;
      t  = [0:1/at1.fs:Nsecs-1/at1.fs].';
      % Compute antialiasing filter (iir filter)
      pl = plist('type', 'lowpass', 'order', 8, 'fs', at1.fs,'fc', 0.9*(at1.fs/2));
      f = miir(pl);
      at1_iir = filtfilt(at1, f);
      y_iir = interp1(at1_iir.x, at1_iir.y, t, 'spline', 'extrap');
      % Compute antialiasing filter (fir filter)
      pl = plist('type', 'lowpass', 'order', 64, 'fs', at1.fs, 'fc', 0.9*(at1.fs/2));
      f = mfir(pl);
      at1_fir = filter(at1, f);
      y_fir = interp1(at1_fir.x, at1_fir.y, t, 'spline', 'extrap');

      % Check with iir filter
      if ~isequal(y_iir, out_iir.y), atest = false; end
      if any(abs(t-out_iir.x)>TOL), atest = false; end
      if ~isequal(out_iir.fs, 1/(t(2)-t(1))), atest = false; end
      % Check with fir filter
      if ~isequal(y_fir, out_fir.y), atest = false; end
      if any(abs(t-out_fir.x)>TOL), atest = false; end
      if ~isequal(out_fir.fs, 1/(t(2)-t(1))), atest = false; end
      % </AlgoCode>
    else
      atest = false;
    end

    % Return a result structure
    result = utp_prepare_result(atest, stest, dbstack, mfilename);
  end % END UTP_13

  %% UTP_14

  % <TestDescription>
  %
  % Tests that the fixfs method works with an AO with non evenly sampled data.
  %
  % </TestDescription>
  function result = utp_14

    % <SyntaxDescription>
    %
    % Test that the fixfs method works for an AO with non evenly samples data.
    %
    % </SyntaxDescription>
    msg = '';
    try
      % <SyntaxCode>
      xvals = sort(randn(30,1));
      yvals = randn(30,1);
      pl_ao = plist('xvals', xvals, 'yvals', yvals, 'type', 'tsdata');
      aa    = ao(pl_ao);

      fs  = 13;
      t0  = 7;
      pl  = plist('t0', t0, 'fs', fs);
      out = fixfs(aa, pl);
      % </SyntaxCode>
      stest = true;
    catch err
      disp(err.message)
      msg = err.message;
      stest = false;
    end

    % <AlgoDescription>
    %
    % 1) Check that each output AO contains the correct data.
    % 2) Check that each output contains the correct frequency and start time.
    %
    % </AlgoDescription>

    TOL   = 1e-14;
    atest = true;
    if stest
      % <AlgoCode>
      % Check the output data
      Nsecs = aa.data.nsecs;
      t0 =  aa.data.getX(1);
      t  =  t0 + [0:1/fs:Nsecs-1/fs].';
      y  = interp1(aa.x,aa.y, t, 'spline', 'extrap');
      if ~isequal(y, out.y), msg = 'y values are not equal'; atest = false; end
      if any(abs(t-out.x)>TOL), msg = 'x values are not evenly spaced'; atest = false; end
      % Check 't0' and 'fs'
      if abs(out.fs - fs)>TOL, msg = 'the sample rates are not correct'; atest = false; end
      if ~eq(out.t0, aa.t0), msg = 'the t0 is not correct'; atest = false; end
      % </AlgoCode>
    else
      atest = false;
    end

    % Return a result structure
    result = utp_prepare_result(atest, stest, dbstack, mfilename, msg);
  end % END UTP_14
  
  
end
