A fast and accurate coalescent simulator.
Msprime is a coalescent simulator and library for processing tree-based genetic data. Msprime can simulate the coalescent with recombination over whole chromosomes for hundreds of thousands of samples, and very efficiently process the resulting genealogies. It is also possible to efficiently read data from external sources via a well defined and efficient interchange API.
Please see the documentation for further details.
Msprime is very portable, and provides a number of installation options. See here for details.