Intelligent Systems II · TEE · papers
Q7(c) Point versus uniform crossover [5]
Final examination · 17 Apr 2024
Actual historical paper ·100 marks attempted /140 offered · Q1 compulsory + any four of Q2–Q7. Source defects and solution assumptions are explicitly identified.
Differentiate between point crossover and uniform crossover.
Answer
Crossover recombines genes from two parents to form children. Its purpose is to combine useful building blocks; mutation introduces an independent local change.
| Aspect | Point crossover | Uniform crossover |
|---|---|---|
| Selection mechanism | Choose one or more cut locations; exchange contiguous segments | Choose parent at each position using a binary mask |
| Linkage | Tends to preserve neighboring gene blocks | Mixes genes more independently; may break useful adjacent blocks |
| Control | Number and position of cut points | Mask / per-gene mixing probability |
| Example parents | P1=111100, P2=000011 | Same parents |
| Rule | Cut after position 3: 111|100 and 000|011 | Mask 101010: child 1 takes P1 where mask=1, otherwise P2 |
| Children | 111011 and 000100 | 101001 and 010110 |
For uniform child 1, positions 1–6 are 1(fromP 1),0(P2),1(P1),0(P2),0(P1),1(P2). Child 2 uses the complementary choices. Both methods preserve chromosome length. For permutation encodings such as TSP, naive point/uniform crossover can repeat a city, so use a permutation-preserving method or a declared repair.