Chapter 6 MI500: Exploitation rate results

Here we present the results for best performances found by each selection scheme replicate on the exploitation rate diagnostic with our base configurations. For our base configuration, we assume that there are migrations every 500 generations, 4 islands, and a ring topology. When migrations occur, we swap two individuals (same position on each island) and guarantee that no solution can return to the same island. Best performance found refers to the largest average trait score found in a given population. Note that performance values fall between 0.0 and 100.0.

6.2 Truncation selection

Here we analyze how the different population structures affect truncation selection (size 8) on the exploitation rate diagnostic.

6.2.3 Stats

Summary statistics for the first generation a satisfactory solution is found.

## # A tibble: 3 x 8
##   Structure count na_cnt   min median  mean   max   IQR
##   <fct>     <int>  <int> <int>  <dbl> <dbl> <int> <dbl>
## 1 EA          100      0  3377  3424. 3423.  3472  26.2
## 2 IS          100      0  4680  4752. 4754.  4839  25  
## 3 NMIS        100      0  4733  4790. 4791.  4846  32.5

Kruskal–Wallis test provides evidence of difference among selection schemes.

## 
##  Kruskal-Wallis rank sum test
## 
## data:  Generations by Structure
## Kruskal-Wallis chi-squared = 237.99, df = 2, p-value < 2.2e-16

Results for post-hoc Wilcoxon rank-sum test with a Bonferroni correction.

## 
##  Pairwise comparisons using Wilcoxon rank sum test with continuity correction 
## 
## data:  ssf$Generations and ssf$Structure 
## 
##      EA     IS    
## IS   <2e-16 -     
## NMIS <2e-16 <2e-16
## 
## P value adjustment method: bonferroni

6.3 Tournament selection

Here we analyze how the different population structures affect tournament selection (size 8) on the exploitation rate diagnostic.

6.3.3 Stats

Summary statistics for the first generation a satisfactory solution is found.

## # A tibble: 3 x 8
##   Structure count na_cnt   min median  mean   max   IQR
##   <fct>     <int>  <int> <int>  <dbl> <dbl> <int> <dbl>
## 1 EA          100      0  5392  5446  5449.  5550  41.2
## 2 IS          100      0  5741  5862  5862.  5979  51.2
## 3 NMIS        100      0  5818  5908. 5909.  6002  39.2

Kruskal–Wallis test provides evidence of difference among selection schemes.

## 
##  Kruskal-Wallis rank sum test
## 
## data:  Generations by Structure
## Kruskal-Wallis chi-squared = 226.27, df = 2, p-value < 2.2e-16

Results for post-hoc Wilcoxon rank-sum test with a Bonferroni correction.

## 
##  Pairwise comparisons using Wilcoxon rank sum test with continuity correction 
## 
## data:  ssf$Generations and ssf$Structure 
## 
##      EA      IS     
## IS   < 2e-16 -      
## NMIS < 2e-16 1.1e-14
## 
## P value adjustment method: bonferroni

6.4 Lexicase selection

Here we analyze how the different population structures affect standard lexicase selection on the exploitation rate diagnostic.

6.4.3 Stats

Summary statistics for the first generation a satisfactory solution is found.

## # A tibble: 3 x 8
##   Structure count na_cnt   min median   mean   max   IQR
##   <fct>     <int>  <int> <int>  <dbl>  <dbl> <int> <dbl>
## 1 EA          100      0 22764 25666. 26026. 32687 2344 
## 2 IS          100      0 23649 27080. 27635. 38266 2628.
## 3 NMIS        100      0 24412 27358. 27906. 34604 2396.

Kruskal–Wallis test provides evidence of difference among selection schemes.

## 
##  Kruskal-Wallis rank sum test
## 
## data:  Generations by Structure
## Kruskal-Wallis chi-squared = 52.814, df = 2, p-value = 3.401e-12

Results for post-hoc Wilcoxon rank-sum test with a Bonferroni correction.

## 
##  Pairwise comparisons using Wilcoxon rank sum test with continuity correction 
## 
## data:  ssf$Generations and ssf$Structure 
## 
##      EA      IS  
## IS   3.0e-08 -   
## NMIS 2.2e-11 0.24
## 
## P value adjustment method: bonferroni