| Date | May 2022 | Marks available | 2 | Reference code | 22M.3.HL.TZ0.1 |
| Level | HL | Paper | 3 | Time zone | no time zone |
| Command term | Outline | Question number | 1 | Adapted from | N/A |
Question
Refer to the Paper 3 Case study: Genetic algorithms, available under the "Your tests" tab > supplemental materials.
Outline what is meant by a heuristic algorithm.
Identify two reasons why premature convergence may occur.
Markscheme
Award [2 max]
A heuristic does not guarantee an optimal solution/finds an approximate solution;
Heuristics produce a solution relatively quickly/sacrifices optimisation accuracy for speed;
Used when exact algorithms (e.g. brute force) are impractical/used for computationally intractable problems;
Award [2 max]
Small (initial) population/Lack of diversity in (initial) population;
Failure to preserve population diversity/Genes of high rated individuals dominate the population early in the process; Low/zero mutation rate;
Stopping condition occurs too soon;
Selection strategy that reduces diversity/Elitism;
Crossover strategy that reduces diversity;
Examiners report
Nearly all candidates earned at least one of the two marks. Some failed to gain the second mark for the outline question because their knowledge was incomplete.
Nearly all candidates were able to identify one cause of premature convergence. Many could identify two reasons. Some students focused on the signs rather than the cause of premature convergence.
