function lambda = stetter_lambda ( t )

%*****************************************************************************80
%
%% stetter_deriv evaluates the right hand side of the Stetter ODE.
%
%  Discussion:
%
%    y' = lambda(t) * y
%
%    t   lambda(t)  mod(t,7.5)  mod(t-0.5,7.5)  - mod(t,7.5)/0.5
%  ----- --------   ----------  ----------------------------------------
%    0.0   0         0          7.0                  0
%    0.5  -1         0.5        0                   -1
%    7.5   0         0          7.0                  0
%    8.0  -1         0.5        0                   -1
%   15.0   0         0          7.0                  0
%   15.5  -1         0.5        0                   -1
%   22.5   0
%   23.0  -1
%   30.0   0
%   30.5  -1
%   37.5   0
%   38.0  -1
%   45.0   0
%   45.5  -1
%   52.5   0
%   53.0  -1
%   60.0   0
%   
%  Licensing:
%
%    This code is distributed under the MIT license.
%
%  Modified:
%
%    05 March 2021
%
%  Author:
%
%    John Burkardt
%
%  Input:
%
%    real T the time and solution value.
%
%  Output:
%
%    real LAMBDA: the value of lambda.
%

%
%  T  might be a vector.
%  If so, we need to ensure that it is a column vector.
%
  t = t(:);

  lambda = - mod ( t, 7.5 ) / 0.5;

  return
end

