Unformatted text preview: f not impossible, to estimate. Having computed
a nite element solution, it is possible to obtain a posteriori error estimates which give
more quantitative information about the accuracy of the solution. Many error estimation
techniques are available and before discussing any, let's list some properties that a good
a posteriori error estimation procedure should possess.
The error estimate should give an accurate measure of the discretization error for
a wide range of mesh spacings and polynomial degrees. 7.4. A Posteriori Error Estimation 17 The procedure should be inexpensive relative to the cost of obtaining the nite
element solution. This usually means that error estimates should be calculated
using only local computations, which typically require an e ort comparable to the
cost of generating the sti ness matrix.
A technique that provides estimates of pointwise errors which can subsequently be
used to calculate error measures in several norms is preferable to one that only
works in a speci c norm. Pointwise error estimates and erro...
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