function dydt = lotka_deriv ( t, y )

%*****************************************************************************80
%
%% lotka_deriv() evaluates the right hand side of a Lotka-Volterra ODE.
%
%  Licensing:
%
%    This code is distributed under the MIT license.
%
%  Modified:
%
%    15 July 2024
%
%  Author:
%
%    John Burkardt
%
%  Input:
%
%    real T: the time;
%
%    real Y(1,2): the current solution values.
%
%  Output:
%
%    real DYDT(2,1): the derivative values.
%
  u = y(1);
  v = y(2);

  dudt =    2.0 * u - 0.001 * u * v;
  dvdt = - 10.0 * v + 0.002 * u * v;

  dydt = [ dudt; dvdt ];

  return
end

