next | previous | forward | backward | up | top | index | toc | Macaulay2 web site
RandomComplexes :: RandomComplexes



We implement two methods to create a random ChainComplex over the integers. The first method builds the complex from products of randomly choosen matrices of desired rank. The limitation of this method to produce large complexes over the integers with moderate Height is the use of the LLL algorithm to improve the presentation of syzygy matrices. The second method uses Stanley-Reisner rings from randomly choosen monomial ideals.

Some functionality here should be moved elsewhere.




This documentation describes version 0.2 of RandomComplexes.

Source code

The source code from which this documentation is derived is in the file RandomComplexes.m2.


  • Functions and commands
    • disturb -- disturb the matrices of a chain complex over RR
    • histogram -- histogram of a list of real numbers
    • maximalEntry -- maximal absolute value of the entries of the matrices
    • normalize -- normalize a ChainComplex over QQ or RR
    • randomChainComplex -- random chain complex over the integers with prescribed ranks of the homology group and ranks of the matrices
    • randomSimplicialComplex -- the chainComplex over ZZ of a random Stanley-Reisner simplicial complex
    • testTimeForLLLonSyzygies -- test timing for LLL on syzygies
  • Symbols
    • Continuous, see Discrete -- Value for the Strategy in disturb
    • Discrete -- Value for the Strategy in disturb
    • WithLLL -- Option for randomComplex
    • ZeroMean -- Option for randomComplex