Topology and Meta-Learning

Brief Intro

About Naming

The initial object is to apply topology into meta-learning as a tool for characterisation of datasets. Yet, topology is a bit hard for me at that moment (and now), and thus I switched to an easier, conventional way of doing meta-learning.

Abstract (Copied from published paper)

Meta-features describe the characteristics of the datasets to facilitate algorithm selection. This paper proposes a new set of meta-features based on clustering the instances within datasets. We propose the use of a greedy clustering algorithm, and evaluate the meta-features generated based on the learning curves produced by the Random Forest algorithm. We also compared the utility of the proposed meta-features against pre-existing meta-features described in the literature, and evaluated the applicability of these meta-features over a sample of UCI datasets. Our results show that these meta-features do indeed improve the performance when applied to the algorithm selection task.

Structure

All scripts are coded for Python3.6/3.7

• ./requirement.txt
  • Dependencies to run scripts in this repository
  • Outdated, please refer to the import list at the top of each script
• ./convex_hull_cluster.py
  • Greedy algorithm with high time complexity
  • Use convex hulls to cluster the instances while ensuring homogeneity
  • Dependency
    • Internal: ./meta_features.py
    • External: numpy, scipy
  • Command example: python3 convex_hull_cluster.py path/to/input/[file]
    • Output files
      • [file].clusters.json: saved clustering results. Can be used to prevent re-calculation
      • [file].output.json: saved results with all meta-features' values calculated
      • [file].log
• ./spherical_cluster.py
  • Greedy algorithm with moderate time complexity
  • Similar to convex hull algorithm but uses spherical clusters instead
  • Dependency
    • Internal: ./meta_features.py
    • External: numpy
  • Command: (-h option for help)
    • E.g.: python3 spherical_cluster.py -r path/to/dir/with/inputs --log path/to/log
    • E.g.: python3 spherical_cluster.py -i path/to/input/file
  • Output files:
    • [input].cluaters.json: saved clustering results
      • Cannot be used to restore clustering results
      • (Too lazy to implement)
    • [input].output.json: saved results with all meta-features' values calculated
• ./sperical_brute_force.py
  • Brute force algorithm for optimal clustering result with the constraint of spherical clusters. Extremely high time complexity
    • Enumerate and check every possible combination of splitting the dataset into subsets
  • [Same as "./spherical_cluster.py" above]
• ./meta_features.py
  • Separate module to calculate meta-features with clustering results
  • Do not run it directly
• ./learning_rate.py
• utilities/
  • utilities/extract_meta_features.py:
    • Extract meta-features from .clusters.json (raw clustering results file), not .output.json (suppose to contain meta-features, but depreciated)

[WIP]