“final3
2005/1
page xv
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List of Figures xvii
14.10 The nonconvex domain in which the PDE is defined. ...........309
14.11 The original coarse mesh that gives a poor approximation to the noncon-
vex domain. .................................310
14.12 The refined mesh that gives a better approximation to the nonconvex
domain. ...................................310
15.1 The reference triangle in the quadratic finite-element method. The nodes
are numbered 1, 2, 3, 4, 5, 6. A typical quadratic nodal function assumes
the value 1 at one of these nodes and 0 at the others. ...........315
15.2 The reference triangle in the cubic finite-element method. The nodes
are numbered 1, 2, 3, 4, 5, 6, 7, 8, 9, 10. A typical cubic nodal function
assumes the value 1 at one of these nodes and 0 at the others. .......316
16.1 Schematic representation of inheritance from the base class "connect-
edList<rowElement>" to the derived class "row". .............329
16.2 Thehierarchyof objects usedtoimplement thesparsematrix: the"sparse-
Matrix" object is a list of "row" objects, each of which is a connected list
of "rowElement" objects, which use the template ’T’ to refer to the type
of value of the matrix elements. ......................334
16.3 Schematic representation of inheritance from the base class "list<row>"
to the derived class "sparseMatrix". ....................335
17.1 The multigrid iteration has the shape of the letter V: first, relaxation is
used at the fine grid; then, the residual is transferred to the next, coarser,
grid, where a smaller V-cycle is used recursively to produce a correction
term, which is transferred back to the fine grid; finally, relaxation is used
again at the fine grid. ............................354
17.2 The "multigrid" object contains the square matrices A, U, and L and the
rectangular matrices R and P , which are used to transfer information to
and from the coarse grid. ..........................356
17.3 The domain decomposition. The bullets denote nodes in the coarse
grid c.....................................363
17.4 The first prolongation step, in which the known values at the bullets
are prolonged to the line connecting them by solving a homogeneous
subproblem in the strip that contains this line. ...............363
17.5 The second prolongation step, in which the known values at the bullets
and edges are prolonged to the interior of the subdomain by solving a
homogeneous Dirichlet subproblem. ....................364
17.6 Prolonging to node i by solving a homogeneous Dirichlet–Neumann sub-
problem in the “molecule” of finite elements that surround it. .......365
18.1 Thecache-oriented relaxation fora tridiagonalsystem: firstpart, in which
the unknowns in each chunk are relaxed over and over again using data
from the previous relaxation. ........................372