function p = predator_prey_period_linear ( )

%*****************************************************************************80
%
%% predator_prey_period_linear() estimates the period of predator_prey_ode().
%
%  Discussion:
%
%    The period estimate of Lotka is based on the linear terms only.
%
%  Licensing:
%
%    This code is distributed under the MIT license.
%
%  Modified:
%
%    17 December 2021
%
%  Author:
%
%    John Burkardt
%
%  Reference:
%
%    Alfred Lotka,
%    Undamped oscillations derived from the law of mass action,
%    Journal of the American Chemical Society,
%    Volume 42, 1920, pages 1595-1599.
%
%  Output:
%
%    real P: the estimated period.
%
  [ alpha, beta, gamma, delta, t0, y0, tstop ] = predator_prey_parameters ( );

  p = 2.0 * pi / sqrt ( alpha * gamma );

  return
end

