%GENREGSIN Generate sinusoidal regression data%%     X = GENDATSIN(N,SIGMA)%% INPUT%    N      Number of objects to generate%    SIGMA  Standard deviation of the noise%% OUTPUT%    X      Regression dataset%% DESCRIPTION% Generate an artificial regression dataset [X,Y] with:%%    y = sin(4x) + noise. %% where noise is Gaussian distributed with standard deviation sigma.%%  X = GENDATSIN(100)% generates 100 x,y pairs with data and default noise (sigma = 0.1).%%  x = (0:0.01:1)';%  y = genregsin(x,0);% generates the true function along the x-axis, with zero noise.%% SEE ALSO% GENDATR, GENDATSINC% Copyright: D.M.J. Tax, D.M.J.Tax@prtools.org% Faculty EWI, Delft University of Technology% P.O. Box 5031, 2600 GA Delft, The Netherlandsfunction x = gendatsin(nrx,noise)if nargin<2  noise = 0.1;endif (length(nrx)>1)  x = nrx;  nrx = size(x);  x = sin(4*x) + noise*randn(nrx);else  x = rand(nrx,1);  y = sin(4*x) + noise*randn(nrx,1);endx = gendatr(x,y);return