In the standard run reported in the previous chapter, CPU-time was
distributed to the programs according to their length; longer programs were
allowed to execute more instructions per time slice. Recall from
Section 4.2.3 that the number of
instructions, N, that a program of length L can execute at each time
slice (provided it has enough stored energy tokens) is governed by the
two parameters et_value_constant and et_value_power
as follows:
In the standard run, the values of these parameters were 0.025 and 1.0
respectively. In that run, the program length actually increased
during the course of evolution, as described in
Sections 5.2.1 and 5.2.7. To see
whether this pattern could be repeated in the face of greater
selective pressure for shorter programs, the run was repeated
using the parameter values shown in Table 6.5. The
values chosen were such that every program was allowed to execute 10
instructions per time slice, regardless of its length.
Table 6.5:
Non-default Parameter Values for CPU-time
Distribution Experiments.
