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NESC9736 SPLPKG, WFCMPR, WFAP

SPLPKG WFCMPR WFAPPX, Wilson-Fowler Spline Generator for Computer Aided Design And Manufacturing (CAD/CAM) Systems

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1. NAME OR DESIGNATION OF PROGRAM:  SPLPKG, WFCMPR, WFAPPX.
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2. COMPUTERS
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Program name Package id Status Status date
SPLPKG/WFCMPR/WFAPPX NESC9736/01 Arrived 14-FEB-2002

Machines used:

Package ID Orig. computer Test computer
NESC9736/01 DEC VAX 11/750
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3. DESCRIPTION OF PROGRAM OR FUNCTION

The three programs SPLPKG, WFCMPR, and WFAPPX provide the capability for interactively generating, comparing and approximating Wilson-Fowler splines. The Wilson-Fowler spline is widely used in Computer Aided Design and Manufacturing (CAD/CAM) systems. It is favored for many applications because it produces a smooth, low curvature fit to planar data points.
Program SPLPKG generates a Wilson-Fowler spline passing through given nodes (with given end conditions) and also generates a piecewise linear approximation to that spline within a user-defined  tolerance. The program may be used to generate a 'desired' spline against which to compare other splines generated by CAD/CAM systems. It may also be used to generate an acceptable approximation to a desired spline in the event that an acceptable spline cannot be generated by the receiving CAD/CAM system. SPLPKG writes an IGES file of points evaluated on the spline and/or a file containing the  spline description.
Program WFCMPR computes the maximum difference between two Wilson-Fowler splines and may be used to verify the spline recomputed by a receiving system. It compares two Wilson-Fowler splines with common nodes and reports the maximum distance between curves (measured perpendicular to segments) and the maximum difference of their tangents (or normals), both computed along the entire length of the splines.
Program WFAPPX computes the maximum difference between a Wilson- Fowler spline and a piecewise linear curve. It may be used to accept or reject a proposed approximation to a desired Wilson-Fowler spline, even if the origin of the approximation is unknown. The maximum deviation between these two curves, and the parameter value  on the spline where it occurs are reported.
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4. METHOD OF SOLUTION:
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5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

Maxima of -
   1600 evaluation points (SPLPKG)
   1000 evaluation points (WFAPPX)
   1000 linear curve breakpoints (WFAPPX)
    100 spline Nodes
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6. TYPICAL RUNNING TIME:
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7. UNUSUAL FEATURES OF THE PROGRAM:
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8. RELATED AND AUXILIARY PROGRAMS

Algorithms used in SPLPKG, WFCMPR,  and WFAPPX were provided by J.D. Emery, BKCD, and W.R. Melvin, LANL. CIRCLE SPLINE (NESC 9602) is a collection of routines used to generate circular splines in two and three dimensions.
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9. STATUS
Package ID Status date Status
NESC9736/01 14-FEB-2002 Masterfiled Arrived
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10. REFERENCES

- W.R. Melvin
  Error Analysis and Uniqueness Properties of the Wilson-Fowler
  Spline,
  LA-9178, August 1982.
- R.M. Dolin and W.R. Oakes
  A Comparison Between the Wilson-Fowler Spline and the Circle
  Spline Routines,
  LA-10522-MS, November 1985.
NESC9736/01, included references:
- Sharon K. Fletcher:
  User's Guide for Wilson-Fowler Spline Software SPLPKG, WFCMPR,
  WFAPPX CADCAM-010,
  SAND84-1161 (February 1985).
- Sharon K. Fletcher:
  CADCAM-007 Recommended Practices for Spline Usage in CAD/CAM
  Systems,
  SAND84-0142 (April 1984).
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11. MACHINE REQUIREMENTS:
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12. PROGRAMMING LANGUAGE(S) USED
Package ID Computer language
NESC9736/01 FORTRAN-77
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13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:
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14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS:
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15. NAME AND ESTABLISHMENT OF AUTHORS

          S.K. Fletcher
          Sandia National Laboratories, Albuquerque
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16. MATERIAL AVAILABLE
NESC9736/01
source program   mag tapeSPLPKG Source File (FORTRAN)               SRCTP
source program   mag tapeWFCMPR Source File (FORTRAN)               SRCTP
source program   mag tapeWFAPPX Source File (FORTRAN)               SRCTP
test-case data   mag tapeSPLPKG sample Problem Input                DATTP
test-case data   mag tapeWFCMPR sample Problem Input                DATTP
test-case data   mag tapeWFAPPX sample Problem Input                DATTP
report                   SAND84-1161 (February 1985)                REPPT
report                   SAND84-0142 (April 1984)                   REPPT
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17. CATEGORIES
  • P. General Mathematical and Computing System Routines

Keywords: algorithms, computer-aided design, spline functions.