Table 1:

Objective | Find an algorithm (i.e., solver) that locates the minimum of a ten-parameter quadratic function (9). |

Terminal set | See (8). |

Function set | See (7). |

Initial population | Ramped half-and-half (tree depth of 5) (Koza, 1992). |

Population size | 200. |

Fitness | An average cost value over ten runs, each time from a different initial simplex and with a different displacement vector. Punish lengths of more than 2,000 characters by multiplying the fitness value by 100. |

Selection | The best 90% of the population automatically pass to an intermediate population (elitist selection). Also, 20% of the population is selected using a tournament selection (tournament size of 2) (Poli et al., 2008) to act as parents in crossover operations. |

Probability for a crossover to occur at a terminal | 10%. |

Tree depth limit | No. |

Mutation | No. |

Decimation | In 50th, 150th, and 350th generations. All the individuals whose fitness is less than 0.1% worse than that of the closest better individual are deleted from the population and replaced with new ones. |

Edit | In every 30th generation, all parts that have no effect are removed from solvers in the current population. |

Termination | After 400 generations. |

Objective | Find an algorithm (i.e., solver) that locates the minimum of a ten-parameter quadratic function (9). |

Terminal set | See (8). |

Function set | See (7). |

Initial population | Ramped half-and-half (tree depth of 5) (Koza, 1992). |

Population size | 200. |

Fitness | An average cost value over ten runs, each time from a different initial simplex and with a different displacement vector. Punish lengths of more than 2,000 characters by multiplying the fitness value by 100. |

Selection | The best 90% of the population automatically pass to an intermediate population (elitist selection). Also, 20% of the population is selected using a tournament selection (tournament size of 2) (Poli et al., 2008) to act as parents in crossover operations. |

Probability for a crossover to occur at a terminal | 10%. |

Tree depth limit | No. |

Mutation | No. |

Decimation | In 50th, 150th, and 350th generations. All the individuals whose fitness is less than 0.1% worse than that of the closest better individual are deleted from the population and replaced with new ones. |

Edit | In every 30th generation, all parts that have no effect are removed from solvers in the current population. |

Termination | After 400 generations. |

See text for details.

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