6,963 research outputs found
Semi-Lagrangian schemes for linear and fully non-linear Hamilton-Jacobi-Bellman equations
We consider the numerical solution of Hamilton-Jacobi-Bellman equations
arising in stochastic control theory. We introduce a class of monotone
approximation schemes relying on monotone interpolation. These schemes converge
under very weak assumptions, including the case of arbitrary degenerate
diffusions. Besides providing a unifying framework that includes several known
first order accurate schemes, stability and convergence results are given,
along with two different robust error estimates. Finally, the method is applied
to a super-replication problem from finance.Comment: to appear in the proceedings of HYP201
Boundary Treatment and Multigrid Preconditioning for Semi-Lagrangian Schemes Applied to Hamilton-Jacobi-Bellman Equations
We analyse two practical aspects that arise in the numerical solution of
Hamilton-Jacobi-Bellman (HJB) equations by a particular class of monotone
approximation schemes known as semi-Lagrangian schemes. These schemes make use
of a wide stencil to achieve convergence and result in discretization matrices
that are less sparse and less local than those coming from standard finite
difference schemes. This leads to computational difficulties not encountered
there. In particular, we consider the overstepping of the domain boundary and
analyse the accuracy and stability of stencil truncation. This truncation
imposes a stricter CFL condition for explicit schemes in the vicinity of
boundaries than in the interior, such that implicit schemes become attractive.
We then study the use of geometric, algebraic and aggregation-based multigrid
preconditioners to solve the resulting discretised systems from implicit time
stepping schemes efficiently. Finally, we illustrate the performance of these
techniques numerically for benchmark test cases from the literature
Multi-stage high order semi-Lagrangian schemes for incompressible flows in Cartesian geometries
Efficient transport algorithms are essential to the numerical resolution of
incompressible fluid flow problems. Semi-Lagrangian methods are widely used in
grid based methods to achieve this aim. The accuracy of the interpolation
strategy then determines the properties of the scheme. We introduce a simple
multi-stage procedure which can easily be used to increase the order of
accuracy of a code based on multi-linear interpolations. This approach is an
extension of a corrective algorithm introduced by Dupont \& Liu (2003, 2007).
This multi-stage procedure can be easily implemented in existing parallel codes
using a domain decomposition strategy, as the communications pattern is
identical to that of the multi-linear scheme. We show how a combination of a
forward and backward error correction can provide a third-order accurate
scheme, thus significantly reducing diffusive effects while retaining a
non-dispersive leading error term.Comment: 14 pages, 10 figure
Some regularity and convergence results for parabolic Hamilton-Jacobi-Bellman equations in bounded domains
We study the approximation of parabolic Hamilton-Jacobi-Bellman (HJB)
equations in bounded domains with strong Dirichlet boundary conditions. We work
under the assumption of the existence of a sufficiently regular barrier
function for the problem to obtain well-posedness and regularity of a related
switching system and the convergence of its components to the HJB equation. In
particular, we show existence of a viscosity solution to the switching system
by a novel construction of sub- and supersolutions and application of Perron's
method. Error bounds for monotone schemes for the HJB equation are then derived
from estimates near the boundary, where the standard regularisation procedure
for viscosity solutions is not applicable, and are found to be of the same
order as known results for the whole space. We deduce error bounds for some
common finite difference and truncated semi-Lagrangian schemes
High-order filtered schemes for time-dependent second order HJB equations
In this paper, we present and analyse a class of "filtered" numerical schemes
for second order Hamilton-Jacobi-Bellman equations. Our approach follows the
ideas introduced in B.D. Froese and A.M. Oberman, Convergent filtered schemes
for the Monge-Amp\`ere partial differential equation, SIAM J. Numer. Anal.,
51(1):423--444, 2013, and more recently applied by other authors to stationary
or time-dependent first order Hamilton-Jacobi equations. For high order
approximation schemes (where "high" stands for greater than one), the
inevitable loss of monotonicity prevents the use of the classical theoretical
results for convergence to viscosity solutions. The work introduces a suitable
local modification of these schemes by "filtering" them with a monotone scheme,
such that they can be proven convergent and still show an overall high order
behaviour for smooth enough solutions. We give theoretical proofs of these
claims and illustrate the behaviour with numerical tests from mathematical
finance, focussing also on the use of backward difference formulae (BDF) for
constructing the high order schemes.Comment: 27 pages, 16 figures, 4 table
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