% -*- texinfo -*-
% @deftypefn {Function File} {@var{out} =} ltifr (@var{a}, @var{b}, @var{w})
% @deftypefnx {Function File} {@var{out} =} ltifr (@var{sys}, @var{w})
% Linear time invariant frequency response of single-input systems.
%
% @strong{Inputs}
% @table @var
% @item a
% @itemx b
% coefficient matrices of @math{dx/dt = A x + B u}
% @item sys
% system data structure
% @item w
% vector of frequencies
% @end table
% @strong{Output}
% @table @var
% @item out
% frequency response, that is:
% @end table
% @iftex
% @tex
% $$ G(j\omega) = (j\omega I-A)^{-1}B $$
% @end tex
% @end iftex
% @ifinfo
% @example
% -1
% G(s) = (jw I-A) B
% @end example
% @end ifinfo
% for complex frequencies @math{s = jw}.
% @end deftypefn