About (from their website):

The Dakota toolkit provides a flexible, extensible interface between analysis codes and iterative systems analysis methods. Dakota contains algorithms for:

• optimization with gradient and nongradient-based methods;
• uncertainty quantification with sampling, reliability, stochastic expansion, and epistemic methods;
• parameter estimation with nonlinear least squares methods; and
• sensitivity/variance analysis with design of experiments and parameter study methods.

These capabilities may be used on their own or as components within advanced strategies such as hybrid optimization, surrogate-based optimization, mixed integer nonlinear programming, or optimization under uncertainty.