  We present LatNet Builder, a software tool to find good parameters for
lattice rules, polynomial lattice rules, and digital nets in base 2, for
quasi-Monte Carlo (QMC) and randomized quasi-Monte Carlo (RQMC) sampling over
the $s$-dimensional unit hypercube. The selection criteria are figures of merit
that give different weights to different subsets of coordinates. They are upper
bounds on the worst-case error (for QMC) or variance (for RQMC) for integrands
rescaled to have a norm of at most one in certain Hilbert spaces of functions.
Various Hilbert spaces, figures of merit, types of constructions, and search
methods are covered by the tool. We provide simple illustrations of what it can
do.
