function f = local_xy ( x , y ) %*****************************************************************************80 % %% LOCAL_XY computes the local minimum function. % % Discussion: % % This function has a local minimum: % % X* = ( 0.28581..., 0.27936...), F(X*) = 5.9225... % % and a global minimum: % % X* = ( -21.026653..., -36.760090...), F(X*) = 0. % % Suggested starting point: % % X = ( 1, 1 ), F(X) = 3.33 * 10^6. % % Licensing: % % This code is distributed under the GNU LGPL license. % % Modified: % % 12 February 2008 % % Author: % % John Burkardt % % Reference: % % David Himmelblau, % Applied Nonlinear Programming, % McGraw Hill, 1972, % ISBN13: 978-0070289215, % LC: T57.8.H55. % % Parameters: % % Input, real X, Y, the argument of the function. % % Output, real F, the value of the function at (X,Y). % f = ( x^2 + 12 * y - 1 )^2 ... + ( 49 * x^2 + 49 * y^2 + 84 * x + 2324 * y - 681 )^2; return end