% -*- texinfo -*- % @deftypefn {Function File} {} starp (@var{P}, @var{K}, @var{ny}, @var{nu}) % % Redheffer star product or upper/lower LFT, respectively. % @example % @group % % +-------+ % --------->| |---------> % | P | % +--->| |---+ ny % | +-------+ | % +-------------------+ % | | % +----------------+ | % | | % | +-------+ | % +--->| |------+ nu % | K | % --------->| |---------> % +-------+ % @end group % @end example % If @var{ny} and @var{nu} ``consume'' all inputs and outputs of % @var{K} then the result is a lower fractional transformation. % If @var{ny} and @var{nu} ``consume'' all inputs and outputs of % @var{P} then the result is an upper fractional transformation. % % @var{ny} and/or @var{nu} may be negative (i.e. negative feedback). % @end deftypefn