e01ea
is the AD Library version of the primal routine
e01eaf.
Based (in the C++ interface) on overload resolution,
e01ea can be used for primal, tangent and adjoint
evaluation. It supports tangents and adjoints of first order.
Note: this function can be used with AD tools other than dco/c++. For details, please contact
NAG.
e01ea
is the AD Library version of the primal routine
e01eaf.
e01eaf generates a triangulation for a given set of two-dimensional points using the method of Renka and Cline.
For further information see
Section 3 in the documentation for
e01eaf.
Cline A K and Renka R L (1984) A storage-efficient method for construction of a Thiessen triangulation Rocky Mountain J. Math. 14 119–139
Renka R L (1984) Algorithm 624: triangulation and interpolation of arbitrarily distributed points in the plane ACM Trans. Math. Software 10 440–442
A brief summary of the AD specific arguments is given below. For the remainder, links are provided to the corresponding argument from the primal routine.
A tooltip popup for all arguments can be found by hovering over the argument name in
Section 2 and in this section.
e01ea preserves all error codes from
e01eaf and in addition can return:
- ${\mathbf{ifail}}=-89$
An unexpected AD error has been triggered by this routine. Please
contact
NAG.
See
Error Handling in the NAG AD Library Introduction for further information.
- ${\mathbf{ifail}}=-199$
The routine was called using a strategy that has not yet been implemented.
See
AD Strategies in the NAG AD Library Introduction for further information.
- ${\mathbf{ifail}}=-444$
A C++ exception was thrown.
The error message will show the details of the C++ exception text.
- ${\mathbf{ifail}}=-899$
Dynamic memory allocation failed for AD.
See
Error Handling in the NAG AD Library Introduction for further information.
Not applicable.
None.
The following examples are variants of the example for
e01eaf,
modified to demonstrate calling the NAG AD Library.
In this example,
e01ea creates a triangulation from a set of data points.
e01eb then evaluates the interpolant at a sample of points using this triangulation. Note that this example is not typical of a realistic problem: the number of data points would normally be larger, so that interpolants can be more accurately evaluated at the fine triangulated grid.
This example also demonstrates how to extract useful information from the data structure returned from
e01ea. The provided routine
convex_hull returns, for the nodes on the boundary of the triangulation, the number of such nodes and the list of indices (ordered in anti-clockwise direction) for these nodes. The provided routine
triang2list returns: the number of triangles, the index of the vertices for each triangle, and whether the triangle has one or more edges on the boundary.