# Q7(c) Point versus uniform crossover [5]

Subject: Intelligent Systems II

Exam: TEE

Reader: https://deep-learning-study-room.vercel.app/is2/#tee/papers/paper-2024-final/q7c

Canonical: https://deep-learning-study-room.vercel.app/read/is2/tee/papers/paper-2024-final--q7c/

Actual historical paper ·100 marks attempted /140 offered · Q1 compulsory + any four of Q2–Q7. Source defects and solution assumptions are explicitly identified.

**Question. Q7(c)** [5 marks · 2024-04-17]

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.