A set of m
data points with rectangular Cartesian coordinates xr,yr
are sorted into panels defined by lines parallel to the y
axes. The intercepts of these lines on the x
axes are given in lamda(i)
, for i = 5,6, … ,px − 4
, for j = 5,6, … ,py − 4
, respectively. The function orders the data so that all points in a panel occur before data in succeeding panels, where the panels are numbered from bottom to top and then left to right, with the usual arrangement of axes, as shown in the diagram. Within a panel the points maintain their original order.
A data point lying exactly on one or more panel sides is taken to be in the highest-numbered panel adjacent to the point. The function does not physically rearrange the data, but provides the array point
which contains a linked list for each panel, pointing to the data in that panel. The total number of panels is (px − 7) × (py − 7)
This function was written to sort two-dimensional data in the manner required by function nag_fit_2dspline_panel (e02da)
. The first 9
parameters of nag_fit_2dspline_sort (e02za)
are the same as the parameters in nag_fit_2dspline_panel (e02da)
which have the same name.