% -*- texinfo -*-
% @deftypefn {Function File} {nvi} = negvolidx (closeprice, vol)
% @deftypefnx {Function File} {nvi} = negvolidx ([closeprice vol])
% @deftypefnx {Function File} {nvi} = negvolidx (closeprice, vol, initnvi)
% @deftypefnx {Function File} {nvi} = negvolidx ([closeprice vol], initnvi)
%
% Compute the negative volume index of a security based on its closing
% price (@var{closeprice}) and @var{vol}ume. They may be given as
% separate arguments or as an nx2 matrix. If given, the @var{initnvi}
% is the starting value of the nvi (default: 100).
%
% The @var{nvi} will always be a column vector.
%
% @seealso{onbalvol, posvolidx}
% @end deftypefn