Remark on Algorithm 761

Abstract

Several improvements to Algorithm 761 are presented. The problems corrected consist of (1) the computation of a determinant in subroutine SDLEQN may result in overflow, (2) subroutine SDTRCH may fail to correctly determine the set of boundary edges, (3) subroutine SDTRTT, which removes long thin triangles from the boundary in order to improve the accuracy of extrapolation, may remove too many triangles, and (4) the nodal derivative estimation procedure, SDPD3P, often fails to achieve cubic precision.