% -*- texinfo -*-
%@deftypefn {Function File} {[@var{yhat}, @var{v}] =} rgdtsmcore (@var{x}, @var{y}, @var{d}, @var{lambda}, [@var{options}])
%
% Smooths @var{y} vs. @var{x} values by Tikhonov regularization.
% Although this function can be used directly, the more feature rich
% function 'regdatasmooth' should be used instead. In addition to
% @var{x} and @var{y}, required input includes the smoothing derivative
% @var{d} and the regularization parameter @var{lambda}. The smooth
% y-values are returned as @var{yhat}. The generalized cross
% validation variance @var{v} may also be returned.
%
% Note: the options have changed~
% Currently supported input options are (multiple options are allowed):
%
%@table @code
%@item 'xhat', @var{vector}
% A vector of x-values to use for the smooth curve; must be
% monotonically increasing and must at least span the data
%@item 'weights', @var{vector}
% A vector of weighting values for fitting each point in the data.
%@item 'relative'
% use relative differences for the goodnes of fit term. Conflicts
% with the 'weights' option.
%@item 'midpointrule'
% use the midpoint rule for the integration terms rather than a direct
% sum; this option conflicts with the option 'xhat'
%@end table
%
% References: Anal. Chem. (2003) 75, 3631; AIChE J. (2006) 52, 325
%@end deftypefn