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Compare the execution runtimes of different implementations of Constraint Handling Rules (CHR)
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CHR Benchmark Suite

Compare the execution runtimes of different implementations of Constraint Handling Rules.

Example Plot for gcd Problem

CHR Systems

The following systems with CHR support are compared. With CHR(X) we denote a CHR system as extension of language X.

In addition to these systems we provide native C and JavaScript implementations of most of the given problems.


The test cases are based on the paper "CCHR: the fastest CHR Implementation, in C." by Wuille, Schrijvers and Demoen (2007). The example problems are:

  • fib: The bottom-up calculation of the Fibonacci numbers.
  • gcd: The calculation of the greatest common divisor of two integers, based on the subtraction-based Euclidean algorithm.
  • leq: A constraint solver for less-equal constraints between variables.
  • primes: An implementation of the Sieve of Eratosthenes to generate prime numbers.
  • ram: A simulator of a Random Access Machine.
  • tak: Implementation of the Takeuchi function.

Due to different features of the examined CHR systems not all tests have been implemented for all systems.


The Makefile contains a large number of targets. For every system (swi, jchr, cchr, chrjs and native c) there are several sub-targets, in particular:

  • system.preinstall: Installation of dependencies and benchmark setup, for example the creation of temporary directories.
  • system.install: Installs the actual system.
  • system.prepare: Preparation tasks for the benchmarks. Usually this includes the compilation of the test source files, for example compile *.jchr files for JCHR.
  • system.clean: Target to delete temporary directories and files. This should be called before the benchmark is executed.
  • system.test: Runs each test once to check if it is executable. This will generally create no output. The tests have been passed if no error occurs.
  • system.bench: Executes the benchmarks for this system.

Apart from these tasks there are further, system dependent sub-targets, for example to benchmark only a single system and single test case.

Run Benchmarks

To install all given systems and prepare the benchmarks, run these two commands:

$ sudo make install
$ sudo make prepare

To start the benchmarks simply call make bench:

$ make bench
## bench=leq
### sys=swi
swi/leq:1 (0,0.00186556577682495)*1696 exp
swi/leq:2 (0,0.00171436494731004)*1803 exp
swi/leq:3 (4.44119496322037e-05,0.00171436494731004)*1766 exp

There is no order in which systems and problems are tested, so leq/swi does not need to be the first.

Because the benchmark for all systems will due several hours, make should be preferred. It will create a bench.out file with the benchmark results.

Plot Benchmark Results

The bench.out file can be used to create a plot with the benchmark results:

make plot

This will create the /plots directory containing a PDF for each problem, for example /plots/bench-gcd-col.pdf.

Citation & Acknowledgements

If you use the CHR Benchmarks in a scientific publication, please cite it as described in CITATION.

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