e01shc evaluates the two-dimensional interpolating function generated by
e01sgc and its first partial derivatives.
e01shc takes as input the interpolant
of a set of scattered data points
, for
, as computed by
e01sgc,
and evaluates the interpolant and its first partial derivatives at the set of points
, for
.
e01shc must only be called after a call to
e01sgc.
This function is derived from the function QS2GRD described by
Renka (1988).
Renka R J (1988) Algorithm 660: QSHEP2D: Quadratic Shepard method for bivariate interpolation of scattered data ACM Trans. Math. Software 14 149–150
Computational errors should be negligible in most practical situations.
Background information to multithreading can be found in the
Multithreading documentation.
Please consult the
X06 Chapter Introduction for information on how to control and interrogate the OpenMP environment used within this function. Please also consult the
Users' Note for your implementation for any additional implementation-specific information.
The time taken for a call to
e01shc will depend in general on the distribution of the data points. If
x and
y are approximately uniformly distributed, then the time taken should be only
. At worst
time will be required.