QSHEP3D - Interpolation of Scattered Data in 3D

QSHEP3D takes a set of data values WDAT(XDAT,YDAT,ZDAT), where the points (XDAT,YDAT,ZDAT) are "scattered" in 3D, and constructs an interpolating function W(X,Y,Z) which matches the given data extends smoothly through 3D space.

QSHEP3D is ACM Transactions on Mathematical Software Algorithm number 661. The original text of any ACM TOMS algorithm is available through the NETLIB web site.

Reference:

R J Renka,
QSHEP3D, Quadratic Shepard method for trivariate interpolation of scattered data,
ACM TOMS, Volume 14, 1988, pages 151-152.

Files you may copy include:

• qshep3d.f90, the source code.
• qshep3d_prb.f90, a sample problem.
• qshep3d_prb.out, sample problem output.

The list of routines includes:

• QSHEP3 defines a smooth trivariate interpolant of scattered 3D data.
• QS3VAL evaluates the interpolant function Q(X,Y,Z) created by QSHEP3.
• QS3GRD computes the value and gradient of the interpolant function.
• GETNP3 finds the closest node to a given point.
• GIVENS constructs a Givens plane rotation.
• ROTATE applies a Givens rotation to two vectors.
• SETUP3 sets up the weighted least-squares fit of the data.
• STORE3 sets up a data structure for N scattered nodes in 3D.

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