Add camel test functions, with three and six humps

ChangeLog

@@ -1,3 +1,12 @@
+2024-08-07  Romain Ait Abdelmalek-Lomenech  <romain.ait@centralesupelec.fr>
+
+	Add camel test functions, with three and six humps
+
+	* examples/test_functions/stk_testfun_sixhumpscamel.m: New tets function.
+	* examples/test_functions/stk_testfun_threehumpscamel.m: New tets function.
+	* admin/octpkg/INDEX: Update Octave package index.
+	* NEWS.md: Advertise the change.
+
 2024-03-28  Romain Ait Abdelmalek-Lomenech  <romain.ait@centralesupelec.fr>
 
 	stk_param_estim.m: Fix nargout condition

NEWS.md

@@ -30,6 +30,14 @@
 
 * `stk_length`: Removed.  (Had been deprecated since 2.7.0.)
 
+## Test functions
+
+* `stk_testfun_threehumpscamel`, `stk_testfun_sixhumpscamel`: New test
+  functions.
+
+* Most test functions in `examples/test_functions` are now also
+  available under the CC0 license (see each file).
+
 -----
 
 

admin/octpkg/INDEX

@@ -307,6 +307,8 @@ Examples: test functions, datasets, etc.
  stk_testfun_hartman4
  stk_testfun_hartman6
  stk_testfun_hartman_generic
+ stk_testfun_sixhumpscamel
+ stk_testfun_threehumpscamel
  stk_testfun_twobumps
  stk_testcase_truss3
  stk_testfun_truss3_bb

examples/test_functions/stk_testfun_sixhumpscamel.m

@@ -0,0 +1,75 @@
+% STK_TESTFUN_SIXHUMPSCAMEL computes the "six humps camel back" function
+%
+% CALL: Y = stk_testfun_sixhumpscamel (X)
+%
+%    computes the value Y of the Hartman4 function at X.
+%
+%    The six humps camel back function is a test function in dimension 2,
+%    which is usually evaluated over [-5, 5]^2.
+%
+% GLOBAL MINIMUM
+%
+%    According to [1], the function has two global minima at
+%
+%       x = [-0.0898, 0.7126]
+%
+%    and
+%
+%       x = [0.0898, -0.7126].
+%
+%    The corresponding function value is:
+%
+%       f(x) = -1.0316.
+%
+% REFERENCES
+%
+%  [1] M. Jamil & X. Yang, A Literature Survey of Benchmark Functions
+%      For Global Optimization Problems. Int. Journal of Mathematical
+%      Modelling and Numerical Optimisation, Vol. 4, No. 2, pp. 150–194
+%      (2013).
+
+% Author
+%
+%    Written in 2024 by Romain Ait Abdelmalek-Lomenech
+%                       <romain.ait@centralesupelec.fr>
+
+% Copying Permission Statement  (this file)
+%
+%    To the extent possible under law, CentraleSupelec has waived all
+%    copyright and related or neighboring rights to
+%    stk_testfun_sixhumpscamel.m.  This work is published from France.
+%
+%    License: CC0  <http://creativecommons.org/publicdomain/zero/1.0/>
+
+% Copying Permission Statement  (STK toolbox as a whole)
+%
+%    This file is part of
+%
+%            STK: a Small (Matlab/Octave) Toolbox for Kriging
+%               (https://github.com/stk-kriging/stk/)
+%
+%    STK is free software: you can redistribute it and/or modify it under
+%    the terms of the GNU General Public License as published by the Free
+%    Software Foundation,  either version 3  of the License, or  (at your
+%    option) any later version.
+%
+%    STK is distributed  in the hope that it will  be useful, but WITHOUT
+%    ANY WARRANTY;  without even the implied  warranty of MERCHANTABILITY
+%    or FITNESS  FOR A  PARTICULAR PURPOSE.  See  the GNU  General Public
+%    License for more details.
+%
+%    You should  have received a copy  of the GNU  General Public License
+%    along with STK.  If not, see <http://www.gnu.org/licenses/>.
+
+function y = stk_testfun_sixhumpscamel (x)
+
+x1 = x(:, 1);
+x2 = x(:, 2);
+
+A = (4 - (2.1 * x1 .^ 2) + (x1 .^ 4) / 3) .* (x1 .^ 2);
+B = x1 .* x2;
+C = 4 * (x2 .^ 2 - 1) .* (x2 .^ 2);
+
+y = A + B + C;
+
+end % function

examples/test_functions/stk_testfun_threehumpscamel.m

@@ -0,0 +1,71 @@
+% STK_TESTFUN_THREEHUMPSCAMEL computes the "three humps camel back" function
+%
+% CALL: Y = stk_testfun_threehumpscamel (X)
+%
+%    computes the value Y of the Hartman4 function at X.
+%
+%    The six humps camel back function is a test function in dimension 2,
+%    which is usually evaluated over [-5, 5]^2.
+%
+% GLOBAL MINIMUM
+%
+%    According to [1], the function has one global minimum at
+%
+%       x = [0, 0].
+%
+%    The corresponding function value is:
+%
+%       f(x) = 0.
+%
+% REFERENCES
+%
+%  [1] M. Jamil & X. Yang, A Literature Survey of Benchmark Functions
+%      For Global Optimization Problems. Int. Journal of Mathematical
+%      Modelling and Numerical Optimisation, Vol. 4, No. 2, pp. 150–194
+%      (2013).
+
+% Author
+%
+%    Written in 2024 by Romain Ait Abdelmalek-Lomenech
+%                       <romain.ait@centralesupelec.fr>
+
+% Copying Permission Statement  (this file)
+%
+%    To the extent possible under law, CentraleSupelec has waived all
+%    copyright and related or neighboring rights to
+%    stk_testfun_threehumpscamel.m.  This work is published from France.
+%
+%    License: CC0  <http://creativecommons.org/publicdomain/zero/1.0/>
+
+% Copying Permission Statement  (STK toolbox as a whole)
+%
+%    This file is part of
+%
+%            STK: a Small (Matlab/Octave) Toolbox for Kriging
+%               (https://github.com/stk-kriging/stk/)
+%
+%    STK is free software: you can redistribute it and/or modify it under
+%    the terms of the GNU General Public License as published by the Free
+%    Software Foundation,  either version 3  of the License, or  (at your
+%    option) any later version.
+%
+%    STK is distributed  in the hope that it will  be useful, but WITHOUT
+%    ANY WARRANTY;  without even the implied  warranty of MERCHANTABILITY
+%    or FITNESS  FOR A  PARTICULAR PURPOSE.  See  the GNU  General Public
+%    License for more details.
+%
+%    You should  have received a copy  of the GNU  General Public License
+%    along with STK.  If not, see <http://www.gnu.org/licenses/>.
+
+function y = stk_testfun_threehumpscamel (x)
+
+x1 = x(:, 1);
+x2 = x(:, 2);
+
+A = (2 * x1 .^ 2) - (1.05 * x1 .^ 4) + (x1 .^ 6 / 6);
+B = x1 .* x2;
+C = x2 .^ 2;
+
+y = A + B + C;
+
+end % function