 ANCELOT B

is the latest release of LANCELOT,
and is designed to solve largescale optimization problems
involving the minimization of a nonlinear objective, subject
(perhaps) to linear or nonlinear equality and box
constraints. All functions involved are assumed to be group
partially separable, and the minimization is based on a
Sequential Augmented Lagrangian algorithm. The new release
is coded in Fortran 95, allows for a nonmonotone
descent strategy, Moré and Toraldotype projections,
optional use of Lin and Moré's
ICFS
preconditioner, structured trust regions, and more.
 ANCELOT_SIMPLE

is a simpleminded interface to LANCELOT
for small, dense problems.
 ILTRANE

is a package for finding a feasible point
for a set of linear and/or nonlinear equations and
inequalities using a multidimensional filter trustregion
approach. In the event that the system is inconsistent, a
local measure of infeasibility is minimized. Core linear
algebraic requirements are handled by an adaptive
preconditioned CG/Lanczos iteration.
 RU

solves the unconstrained optimization
problem using a trustregion method.
Both direct and iterative solution of core subproblems
is possible, and there are many other
"bells and whistles".
 RC

solves the same
problem using an adaptive cubic regularization method.
Most of the features available with TRU are also
present here.
 P

provides a unified interface to all
the GALAHAD quadratic programs packages and enables
optional automatic problem scaling and pre/postsolution.
 PB

solves quadratic programs using a
primaldual interiorpoint method globalized by means of a
trust region. The method works in two phases, the first
finding a feasible point for the set of constraints, while
the second maintaining feasibility while iterating towards
optimality. Once again, core linear algebraic requirements
are handled by an adaptive preconditioned CG/Lanczos
iteration.
 PA

is an activeset quadratic programming
solver which can also treat l_1 quadratic programs. At each
iteration, a step is computed along a direction which solves
an equalityconstrained quadratic program whose constraints
are defined by a working subset of the currently active
constraints. Although, in general, QPB is to be preferred,
QPA is most useful when warmstarting a perturbation of a
previouslysolved problem.
 PC

is a crossover quadratic programming
solver which applies successively QPB and QPA. The former is
used to obtain a good estimate of the solution at low cost,
while the latter refines the solution. Of particular note,
the optimal active set given by QPC is more reliable than
that from QPB.
 SQP

uses a primaldual interiorpoint method
to solve a linear or separable convex quadratic program.
Alternatively, it may also be used to compute the analytic
center of the feasible set, if it exists.
 CP

uses a primaldual interiorpoint method
to find a wellcentered interior point for a region defined
by a finite number of linear equality and inequality
constraints. If the region is feasible but has no interior,
inequality constraints which must always be active are
identified.
 QP

solves convex quadratic programs using a
highorder primaldual extrapolation methd. The main
design feature is to allow fast convergence even when
the problem is degenerate using Puiseux rather than Taylor
expansions.
 RESOLVE

is a quadratic program preprocessor. It
aims to apply inexpensive transformations to a given
quadratic program, so as to simplify it before passing it to
one of the other GALAHAD solvers. Once the solver has
completed its task, a postprocessing stage may be used to
recover the original problem and its solution.
 CALE

provides a variety of quadratic program
scaling schemes that try to remove the effects of poor
problem scaling.
 RS

solves the problem of minimizing a
quadratic subject to an ellipsoidal trustregion constraint,
by sparsematrix factorizaion. The algorithm may also be
used to minimize the quadratic over the boundary of the
trust region, and allows additional linear equality
constraints
 QS

solves the problem of minimizing a
quadratic subject plus a regularisation term penalising a
weighted twonorm of the variables, by sparsematrix
factorizaion. Again, the algorithm permits additional linear
equality constraints
 LTR

solves the problem of minimizing a
quadratic subject to an ellipsoidal trustregion constraint,
using a Krylov method. The algorithm does not require any
factorization of the Hessian and may also be used to
minimize the quadratic over the boundary of the trust
region.
 LRT

solves the problem of minimizing a
quadratic subject plus a regularisation term penalising a
weighted twonorm of the variables, using a Krylov method.
Again, the algorithm does not require any factorization of
the Hessian.
 STR

solves the problem of minimizing the
twonorn of the deviation Axb subject to an ellipsoidal
trustregion constraint, using a Krylov method. The
algorithm does not require any factorization of A.
 SRT

solves the problem of minimizing the
square of the twonorn of the deviation Axb plus a
regularisation term penalising the twonorm of the
variables, using a Krylov method. Again, the algorithm does
not require any factorization of A.
 2RT

solves the problem of minimizing the
twonorn of the deviation Axb plus a regularisation term
penalising the twonorm of the variables, using a Krylov
method. Once again, the algorithm does not require any
factorization of A.
 QP

solves quadratic programming problems for
which all the constraints are equations.
 DC

determines whether a system of linear
equations is of full rank, and identifies a maximal subset
which may be removed without changing the rank
 BLS

provides a variety of preconditioners
which may be applied when solving saddle point
(alternatively augmented, KKT) systems of linear
equations.
 LS

provides a generic interface
to a variety of external symmetric linear equation solvers
(HSL, PARDISO, WSMP), some of which are designed
for fast solution on sharedmemory multiprocressing system.
Outofcore solution is also supported.
 LS

provides a generic interface
to a variety of external unsymmetric linear equation solvers
from HSL. Future support for other solvers is planned.