function [X, y, conf] = get_data(conf, field)%% Get training or test data for a simulated learning problem.%% The input data is returned in X, the output in y. Optional% parameters are controlled by fields in the structure conf.%% For further details of the function see:%%  'Matlab Routines for RBF Networks', 1999.% % Program name (for error messages)prog = 'get_data';% Configuration spec.spec(1) = struct( ...  'comment', 'Problem name', ...  'name',    'name', ...  'type',    'string', ...  'options', {{'sine1', 'sine2', {'mackay', 'hermite'}, {'friedman', 'sacc'}}}, ...  'default', []);spec(2) = struct( ...  'comment', 'Number of samples', ...  'name',    'p', ...  'type',    {{'number', 'integer', 'positive'}}, ...  'options', [], ...  'default', []);spec(3) = struct( ...  'comment', 'Lower limits for input components', ...  'name',    'x1', ...  'type',    'column vector', ...  'options', [], ...  'default', []);spec(4) = struct( ...  'comment', 'Upper limits for input components', ...  'name',    'x2', ...  'type',    'column vector', ...  'options', [], ...  'default', []);spec(5) = struct( ...  'comment', 'Function parameter values', ...  'name',    'par', ...  'type',    'vector', ...  'options', [], ...  'default', []);spec(6) = struct( ...  'comment', 'Function parameter descriptions', ...  'name',    'pinfo', ...  'type',    'cellstr', ...  'options', [], ...  'default', []);spec(7) = struct( ...  'comment', 'Output component', ...  'name',    'comp', ...  'type',    {{'number', 'integer', 'positive'}}, ...  'options', [], ...  'default', []);spec(8) = struct( ...  'comment', 'Standard deviation of the noise', ...  'name',    'std', ...  'type',    {{'vector', 'nonnegative'}}, ...  'options', [], ...  'default', []);spec(9) = struct( ...  'comment', 'Ordered inputs', ...  'name',    'ord', ...  'type',    'number', ...  'options', {{0 1}}, ...  'default', []);spec(10) = struct( ...  'comment', 'Normalised inputs', ...  'name',    'norm', ...  'type',    'number', ...  'options', {{0 1}}, ...  'default', []);% sine1 defaults.sine1.p = 100;sine1.x1 = -1;sine1.x2 = 1;sine1.par = [0.8 6];sine1.pinfo = {'amplitude'; 'frequency'};sine1.comp = 1;sine1.std = 0.1;sine1.ord = 0;sine1.norm = 0;% sine2 defaults.sine2.p = 200;sine2.x1 = [0; -5];sine2.x2 = [10; 5];sine2.par = [0.8 0.25 0.5];sine2.pinfo = {'amplitude'; 'frequency-1'; 'frequency-2'};sine2.comp = 1;sine2.std = 0.1;sine2.ord = 0;sine2.norm = 0;% mackay defaults.mackay.p = 100;mackay.x1 = -4;mackay.x2 = 4;mackay.par = [];mackay.pinfo = [];mackay.comp = 1;mackay.std = 0.1;mackay.ord = 0;mackay.norm = 0;% friedman defaults.friedman.p = 200;friedman.x1 = [40 * pi; 1; 0; 1e-6];friedman.x2 = [560 * pi; 100; 1; 11e-6];friedman.par = [];friedman.pinfo = [];friedman.comp = 1;friedman.std = [175; 0.44];friedman.ord = 0;friedman.norm = 1;% Input dimensions (not part of conf).sine1.d = 1;sine2.d = 2;mackay.d = 1;friedman.d = 4;% Output dimensions (not part of conf).sine1.n = 1;sine2.n = 1;mackay.n = 1;friedman.n = 2;% Check input argument(s).switch nargincase 1  % conf should either be a string or a struct.  if isstring(conf)    % Take special action if it's a string.    switch conf    case 'conf'      conf_print(prog, spec)      return    case 'demo'      [mydemo, myclean] = eval(['demo_' prog])      run_demo(mydemo, myclean)      return    case {'last', 'prev'}      [X, y, conf] = uncache(prog);      return    case 'names'      options = spec(1).options;      fprintf('Recognised data set names are (in/out dims in brackets):\n')      for o = 1:length(options)        fprintf('  ')        if ischar(options{o})          fprintf('''%s'' (%d/%d)', options{o}, eval([options{o} '.d']), eval([options{o} '.n']))        else          alts = options{o};          for a = 1:length(alts)            if a ~= 1              fprintf(' or ')            end            fprintf('''%s''', alts{a})          end          fprintf(' (%d/%d)', eval([alts{1} '.d']), eval([alts{1} '.n']))        end        fprintf('\n')      end      return    otherwise      % Assume it's a problem name.      conf.name = conf;    end  elseif ~isstruct(conf)    % If it's not a string it should be a struct.    error([prog ': argument (conf) should be string or struct'])  endcase 2  % Two arguments should only mean 'conf' plus a field name.  if isstring(conf) & isstring(field)    conf_print(prog, spec, field)    return  else    error([prog ': arguments (conf, field) should be strings'])  endotherwise  error([prog ': takes either 1 or 2 arguments'])end% Check the configuration is okay and set defaults (if required).conf = conf_check(conf, spec, prog);% The problem name must be supplied.if isempty(conf.name)  error([prog ': the problem name must be supplied'])else  name = conf.name;end% Checks and defaults that depend on problem name.if isempty(conf.p)  conf.p = eval([name '.p']);endif isempty(conf.par)  % Special treatment because default can be [] which doesn't match 'vector'.  def = eval([name '.par']);  if isempty(def)    conf = rmfield(conf, 'par');  else    conf.par = eval([name '.par']);  endelse  if length(conf.par) ~= length(eval([name '.par']))    error([prog ': conf.par has wrong length for the ''' name ''' problem'])  endendif isempty(conf.pinfo)  % Also special treatment because default can be [] which doesn't match 'cellstr'.  def = eval([name '.pinfo']);  if isempty(def)    conf = rmfield(conf, 'pinfo');  else    conf.pinfo = eval([name '.pinfo']);  endelse  if length(conf.pinfo) ~= length(eval([name '.pinfo']))    error([prog ': conf.pinfo has wrong length for the ''' name ''' problem'])  endendif isempty(conf.x1)  conf.x1 = eval([name '.x1']);else  if length(conf.x1) ~= eval([name '.d'])    error([prog ': conf.x1 has wrong length for the ''' name ''' problem'])  endendif isempty(conf.x2)  conf.x2 = eval([name '.x2']);else  if length(conf.x2) ~= eval([name '.d'])    error([prog ': conf.x2 has wrong length for the ''' name ''' problem'])  endendif isempty(conf.comp)  conf.comp = eval([name '.comp']);else  if conf.comp > eval([name '.d'])    error([prog ': conf.comp is too big for the ''' name ''' problem'])  endendif isempty(conf.std)  conf.std = eval([name '.std']);else  if length(conf.std) ~= length(eval([name '.std'])) & length(conf.std) ~= 1    error([prog ': conf.std has wrong length for the ''' name ''' problem'])  endendif isempty(conf.ord)  conf.ord = eval([name '.ord']);endif isempty(conf.norm)  conf.norm = eval([name '.norm']);end% Some useful parameters.p = conf.p;d = eval([name '.d']);w = conf.x2 - conf.x1;m = (conf.x2 + conf.x1) / 2;x1 = conf.x1;x2 = conf.x2;% Inputs.if conf.ord  if d == 1    X = linspace(x1, x2, p);  else    % Number of samples (conf.p) may change.    q = round(10^(log10(p)/d));    p = q^d;    conf.p = p;    x = zeros(d,q);    for k = 1:d      x(k,:) = linspace(x1(k), x2(k), q);    end    X = zeros(d,p);    for k = 1:d      r = q^(d-k);      j = 1;      for i = 1:p        X(k,i) = x(k,j);        if rem(i,r) == 0          j = j + 1;          if j > q            j = 1;          end        end      end    end  endelse  X = x1(:,ones(1,p)) + rand(d,p) .* w(:,ones(1,p));end% OK, generate the data.switch namecase 'sine1'  y = conf.par(1) * sin(conf.par(2)*X)';case 'sine2'  y = conf.par(1) * (cos(conf.par(2)*X(1,:)) .* sin(conf.par(3)*X(2,:)))';case 'mackay'  y = 1 + ((1 - X + 2 * X.^2) .* exp(-X.^2))';case 'friedman'  f = X(1,:);  r = X(2,:);  i = X(3,:);  c = X(4,:);  if conf.comp == 1    y = sqrt(r.^2 + (f.*i - 1./(f.*c)).^2)';  else    y = atan((f.*i - 1./(f.*c))./r)';  endend% Add noise.if length(conf.std) > 1  std = conf.std(conf.comp);else  std = conf.std;endif std > 0  y = y + std * randn(p,1);end% Normalise? Gives +/- 1 as extremes.if conf.norm  X = 2 * ((X - m(:,ones(1,conf.p))) ./ w(:,ones(1,conf.p)));end% Save the data set if it involves any randomness.if conf.ord == 0 | conf.std > 0  cache(prog, X, y, conf);end% Cache data.function cache(prog, X, y, conf)% See if we can find the cache file.me = which([prog '.mat']);% If not, use the location of the script.if isempty(me)  me = which([prog '.m']);end% Otherwise, give up.if isempty(me)  error([prog ': can''t cache results (probably means a problem with PATH)'])end% Work out where home is.i = findstr(prog, me);home = me(1:(i-1));% Save the data.save([home prog '.mat'], 'X', 'y', 'conf')function [X, y, conf] = uncache(prog)% Check [prog '.mat'] can be found on the path.me = which([prog '.mat']);if isempty(me)  error([prog 'can''t locate cache file'])end% Load it.load(me)% Check it has the right data.if ~exist('X', 'var') | ~exist('y', 'var') | ~exist('conf', 'var')  error([prog ': cache file is corrupt'])end