function A = mac1_adjacency ( )

%*****************************************************************************80
%
%% mac1_adjacency() returns the adjacency matrix for MacCormick's example 1.
%
%  Discussion:
%
%    This matrix appears on page 35 of the reference.
%
%  Licensing:
%
%    This code is distributed under the MIT license.
%
%  Modified:
%
%    01 March 2020
%
%  Author:
%
%    John Burkardt
%
%  Reference:
%
%    John MacCormick,
%    Nine Algorithms That Changed the Future: The Ingenious Ideas that 
%    Drive Today's Computers,
%    Princeton University Press,
%    ISBN-13: 978-0691158198.
%
%  Output:
%
%    integer A(5,5), the adjacency matrix.
%
  A = zeros ( 5, 5 );

  A(1,2) = 1.0;
  A(2,5) = 1.0;
  A(3,1) = 1.0;
  A(4,1) = 1.0;
  A(5,1) = 1.0;

  return
end
