6533b858fe1ef96bd12b6d4f

RESEARCH PRODUCT

On a global superconvergence of the gradient of linear triangular elements

Pekka NeittaanmäkiMichal Křížek

subject

Applied MathematicsMathematical analysisOrder of accuracySuperconvergenceglobal superconvergence for the gradientComputer Science::Numerical AnalysisGlobal superconvergence for the gradientMathematics::Numerical AnalysisNonlinear conjugate gradient methodElliptic curveComputational Mathematicserror estimatesNorm (mathematics)boundary fluxPiecewisepost-processing of the Ritz—Galerkin schemeGradient descentGradient methodMathematics

description

Abstract We study a simple superconvergent scheme which recovers the gradient when solving a second-order elliptic problem in the plane by the usual linear elements. The recovered gradient globally approximates the true gradient even by one order of accuracy higher in the L 2 -norm than the piecewise constant gradient of the Ritz—Galerkin solution. A superconvergent approximation to the boundary flux is presented as well.

10.1016/0377-0427(87)90018-5http://dx.doi.org/10.1016/0377-0427(87)90018-5