QSHEP2D - Interpolation of Scattered Data in the Plane

QSHEP2D takes a set of data values ZDAT(XDAT,YDAT), where the points (XDAT,YDAT) are "scattered" in the plane, and constructs an interpolating function Z(X,Y) which matches the given data, and extends smoothly through the plane.

QSHEP2D is ACM Transactions on Mathematical Software Algorithm number 660. The original text of any ACM TOMS algorithm is available through the NETLIB web site.

Reference:

R J Renka,
QSHEP2D, Quadratic Shepard method for bivariate interpolation of scattered data,
ACM TOMS, Volume 14, 1988, pages 149-150.

Files you may copy include:

• qshep2d.f90, the source code.
• qshep2d_prb.f90, a sample problem.
• qshep2d_prb.out, sample problem output.

The list of routines includes:

• GETNP2 seeks the closest unmarked node to a point.
• GIVENS constructs a Givens plane rotation.
• QS2GRD evaluates the interpolant and its first spatial derivatives.
• QSHEP2 computes an interpolant to scattered data in the plane.
• QS2VAL evaluates the interpolant function at a point.
• ROTATE applies a Givens rotation.
• SETUP2 sets up a row of the least squares regression matrix.
• STORE2 creates a cell data structure for the scattered data.

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