https://github.com/gbathie/property_test_regular

Efficient C++ implementation of a property tester for regular expressions/languages.
https://github.com/gbathie/property_test_regular

publication-code regex regular-languages sublinear-algorithms

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Efficient C++ implementation of a property tester for regular expressions/languages.

• Host: GitHub
• URL: https://github.com/gbathie/property_test_regular
• Owner: GBathie
• License: mit
• Created: 2020-08-03T13:48:29.000Z (almost 5 years ago)
• Default Branch: master
• Last Pushed: 2020-08-05T16:20:03.000Z (almost 5 years ago)
• Last Synced: 2023-12-11T18:52:25.521Z (over 1 year ago)
• Topics: publication-code, regex, regular-languages, sublinear-algorithms
• Language: C++
• Homepage:
• Size: 84 KB
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# Property testing of regular languages

Efficient C++ header-contained implementation of a property tester for regular languages 

(i.e. sets of words defined by regular expressions), by Gabriel Bathie.   

This is part of the work I did during my research internship  under the supervision of Tatiana Starikovskaya at ENS Ulm during the summer 2020.  

Our publication with details on the analysis of the algorithm can be found online here (not yet available, todo).

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### Usage

Simply include `property_tester.h` in your project, and add `nfa.h` and `property_tester.h` to your include path.  

Examples of creation of an NFA and usage of the property testing algorithm can be found in `example.cpp`.  

To compile the example, use  `make example`.

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### Tests

Here may be found the results of the `tests.cpp` program when compiled and ran on my computer.

Results for the NFA for `0^*1^*`:

![01star](./figures/time01.png "Results for 0^*1^*")

Results for a random NFA with `10` states:

![random_nfa](./figures/time_random.png "Results for a random NFA with 10 states")

As expected, the property testing algorithm is much faster than the exact algorithm 

when the input is large, and tends to a constant time complexity.

The runtime is not exactly constant because letters that appear in multiple samples

are only queried once. The larger the input is, the less overlapping queries there are (on average), 

and therefore the number of queries (and the runtime) increases slightly.

To compile the test program, run `make tests`.

Run the resulting `./tests` file, and then run `python generate_graphs.py` to generate graphs as seen above.

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### Warnings

When using functions `Nfa::accepts` an `property_test` on literal strings 

(that is characters in between double quotes, e.g. `"Hello world"`), 

one must either convert the literals to `std::strings` explicitely

or explicitely call the functions with the template argument  `Container = std::string`,

otherwise the trailing null character `\0` is added to the literal, which makes the automaton reject.

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