## 4.3 Survival of the fittest and selection

variable bestFrac

Meaning: Fraction of the current generation that shall be used to produce the next generation.

Default: 0.7

Format:

0.7 : bestFrac

Note: This is an important parameter, values between 0.5–0.8 are reasonable.

variable keepBestHM

Meaning: Defines how many best structures will survive into the next generation.

Default: 0.15populationSize

Format:

3 : keepBestHM

variable reoptOld

Meaning: Defines reoptimization of the survived structures. If reoptOld=0, these structures will be left without reoptimization while if reoptOld=1, they will be reoptimized again. Usually reoptOld=0 is a reasonable choice (provided your structure relaxation was high quality).

Default: 0

Format:

1 : reoptOld