Push

A bigger update for the new year:

http://hampshire.edu/lspector/schush.ss

The biggest additions are trivial geography (which was trivial to add 🙂 but which can make a big difference) and error scaling using one form of historically assessed hardness. Here’s the full list of new changes:

20091229: - Added scale-errors parameter to schushgp; when #t this calculates
            scaled errors via the Historically Assessed Hardness (HAH) method (in the
            "current generation / quotient" setting) and uses these scaled errors
            as the basis of selection. HAH is described in:
              Klein, J., and L. Spector. 2008. Genetic Programming with Historically
              Assessed Hardness. In Genetic Programming Theory and Practice VI, edited by
              R. L. Riolo, T. Soule, and B. Worzel, pp. 61-74. New York: Springer-Verlag.
              http://hampshire.edu/lspector/pubs/kleinspector-gptp08-preprint.pdf
            This form of HAH is similar but non-identical (for non-Boolean problems)
            to "implicit fitness sharing" as described by McKay in:
              McKay, R. I. 2001. An investigation of fitness sharing in genetic programming.
              The Australian J. of Intelligent Information Processing Systems, 7(1/2):43–51.
            Also added examples using the scale-errors parameter.
          - Added three schushgp parameters to control the number of iterations of
            automatic simplification performed at various times:
            - report-simplifications:
                the number performed for each schushgp generation report
            - final-report-simplifications:
                the number performed on successful results
            - reproduction-simplifications:
                the number performed by the simplification genetic operator
          - Fixed bug in cases for factorial example.
          - Added YANK and YANKDUP instructions for all types.
20100102: - Added trivial geography, controlled by a trivial-geography-radius parameter
            to schushgp; set this to zero (the default) for no trivial geography.
            Trivial geography is described in:
              Spector, L., and J. Klein. 2005. Trivial Geography in Genetic Programming.
              In Genetic Programming Theory and Practice III, edited by T. Yu, R.L. Riolo,
              and B. Worzel, pp. 109-124. Boston, MA: Kluwer Academic Publishers.
              http://hampshire.edu/lspector/pubs/trivial-geography-toappear.pdf
            Also added an example using trivial geography.
          - Made several minor corrections to the documentation.

This entry was posted on January 2, 2010 at 1:06 pm and is filed under Uncategorized.