Sequential Quadratic Programming (SQP) methods are a popular and successful
class of methods for minimizing a generally nonlinear function subject to
nonlinear constraints. Under a standard set of assumptions, conventional SQP
methods exhibit a fast local convergence rate. However, in practice, a
conventional SQP method involves solving an indefinite quadratic program (QP),
which is NP hard. As a result, approximations to the second-derivatives are
often used, slowing the local convergence rate and reducing the chance that the
algorithm will converge to a local minimizer instead of a saddle point. In
addition, the standard assumptions required for convergence often do not hold
in practice. For such problems, regularized SQP methods, which also require
second-derivatives, have been shown to have good local convergence properties;
however, there are few regularized SQP methods that exhibit convergence to a
minimizer from an arbitrary initial starting point. My thesis considers the
formulation, analysis and implementation of: (i) practical methods that use
exact second-derivative information but do not require the solution of an
indefinite QP, (i) a regularized SQP method with global convergence and (iii) a
rigorously defined version of a conventional SQP method with features that have
been observed to work in practice for degenerate problems.