Algorithm 35 an algorithm for non-smoothing contour representations of two-dimensional arrays

Abstract

--Zusammenfassung Algorithm 35. An Algorithm for Non-Smoothing Contour Representations of Two-Dimensional Arrays.The FORTRAN code calculates, plots and labels approximate contour lines z (x, y)= c for data that are given as a rectangular array z,k = z (x~, Yk). The present algorithm has been developed for the study of local energy minima and saddle points in nuclear fission theory. Here the precise assignment of contour lines to grid cells is essential whereas the degree of accuracy achieved within each grid cell is unimportant. Therefore, smooth contour plotting methods that envolve derivatives, small step sizes or curve fitting procedures (like those of Lewis [7], McLain [8], and Sutcliffe [9]) are less appropriate.The correct correspondence between curve and cell is particularly important for contours with degeneracies. Therefore, the present algorithm treats the problems of degenerate cells and degenerate nodes in a proper way. Degenerate nodes are treated without approximations by taking also the corners of each grid celt into account (cf. Fig.