ESTS1197 WFSFIT.

WFSFIT, Wilson-Fowler Spline Fit Algorithm

NAME OR DESIGNATION OF PROGRAM, COMPUTER, DESCRIPTION OF PROGRAM OR FUNCTION, METHODS, RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM, TYPICAL RUNNING TIME, UNUSUAL FEATURES, AUXILIARIES, STATUS, REFERENCES, REQUIREMENTS, LANGUAGE, SOFTWARE REQUIREMENTS, OTHER RESTRICTIONS, NAME AND ESTABLISHMENT OF AUTHORS, MATERIAL, CATEGORIES

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1. NAME OR DESIGNATION OF PROGRAM: WFSFIT.

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2. COMPUTERS

To submit a request, click below on the link of the version you wish to order. Only liaison officers are authorised to submit online requests. Rules for requesters are available here.

Program name	Package id	Status	Status date
WFSFIT	ESTS1197/01	Arrived	23-JAN-2001

Machines used:

Package ID	Orig. computer	Test computer
ESTS1197/01	Many Computers

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3. DESCRIPTION OF PROGRAM OR FUNCTION

WFSFIT is a legacy algorithm introduced in the early 1960s for passing a smooth curve through a planar set of design points. WFSFIT predates b-spline methods, but is still used in some numeric control systems, e.g., APT.

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4. METHODS

In generating a smooth curve, the basic idea is to come as close as possible to the true spline which minimizes the energy of the curve with a curve composed of cubic segments which are joined together to achieve continuous tangent and curvatures. This is accomplished by introducing a local u,v-coordinate system for each segment with the independent variable running along the chord. The curvature matching conditions lead to a tridiagonal nonlinear system of equations which must be solved by an iterative method.

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5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

Numerical accuracy will vary with the format of floating point number representation.

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6. TYPICAL RUNNING TIME

Running time varies with input and is not particularly CPU intensive.

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7. UNUSUAL FEATURES: WFSFIT implements an archaic algorithm.

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8. RELATED OR AUXILIARY PROGRAMS

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9. STATUS

Package ID	Status date	Status
ESTS1197/01	23-JAN-2001	Masterfiled Arrived

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10. REFERENCES

ESTS1197/01, included references:

- Fowler, A.H. and Wilson, C.W.:
Cubic Spline, A Curve Fitting Routine, Y-1400 (Revision 1) (June 28, 1966)
- Fritsch, F.N.:
History of the Wilson-Fowler Spline, UCID-20746 (April 1986)

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11. HARDWARE REQUIREMENTS

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12. PROGRAMMING LANGUAGE(S) USED

Package ID	Computer language
ESTS1197/01	FORTRAN-77

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13. SOFTWARE REQUIREMENTS: WFSFIT runs on any FORTRAN 77 capable computer.

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14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

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15. NAME AND ESTABLISHMENT OF AUTHORS

                 F. Fritsch
                 Lawrence Livermore National Laboratory
                 Livermore, California, U. S. A.

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16. MATERIAL AVAILABLE

ESTS1197/01

Readme  Readme file
nwf03 Source code
nwf16 Source code
splin  data file
spline0.19 data file
splout0.19D
writup0.19  write up file

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17. CATEGORIES

I. Deformation and Stress Distributions, Structural Analysis and Engineering Design Studies
P. General Mathematical and Computing System Routines

Keywords: interpolation, mathematical routines, polynomials, series expansion, spline functions.