**ADMIXTURE** is a software tool for maximum likelihood
estimation of individual ancestries from multilocus SNP genotype
datasets. It uses the same statistical model as **STRUCTURE** but
calculates estimates much more rapidly using a fast numerical
optimization algorithm.

Specifically, **ADMIXTURE** uses a **block relaxation**
approach to alternately update allele frequency and ancestry
fraction parameters. Each block update is handled by solving a
large number of independent convex optimization problems, which are
tackled using a fast **sequential quadratic programming**
algorithm. Convergence of the algorithm is accelerated using a
novel **quasi-Newton acceleration** method. The algorithm
outperforms EM algorithms and MCMC sampling methods by a wide
margin. For details, see
our publications.