.help revisions Jun89 math.curfit
.nf
From Davis, September 20, 1999

Added some missing file dependices to the mkpkg file.
pkg/math/curfit/mkpkg

From Davis, March 20, 1997

The weights computed by the WTS_CHISQ option in the routines cvacpts[rd]
were not being forced to be positive as intended.
math/curfit/cvacpts.gx
math/curfit/cvacptsr.x
math/curfit/cvacptsd.x

There was an inconsistency in the way the ncoeff argument to the cvpower[rd]
routines was being used. Ncoeff was intended to be an output argument.
pkg/math/curfit/doc/cvpower.hlp
pkg/math/curfit/cvpower.gx
pkg/math/curfit/cvpowerr.x
pkg/math/curfit/cvpowerd.x

From Davis, June 13, 1995

Added a new routine cvepower to the curfit math package. Cvepower computes
errors of the equivalent power series coefficients for the fitted Legendre
and Chebyshev polynomials and has the same calling sequence as the 
cverrors routine.
math/curfit/cvpower.gx
math/curfit/cvpowerr.x
math/curfit/cvpowerd.x
math/curfit/doc/curfit.hd
math/curfit/doc/curfit.men
math/curfit/doc/cvepower.hlp

From Davis, May, 6, 1990

Finished cleaning up the .gx files in curfit.
math/curfit/cverrors.gx
math/curfit/cvpower.gx
math/curfit/cvrefit.gx
math/curfit/cvpower.gx

From Davis, May 6, 1990

Changed the constant from INDEFR to INDEF in the amov$t call in cvpower.gx.
This was causing a problem for the Mac compiler.

From Davis, April 23, 1991

Did some cleaning up in the following .gx files to make the code easier to read.
math/curfit/cv_b1eval.gx
math/curfit/cv_beval.gx
math/curfit/cv_feval.gx
math/curfit/cvaccum.gx
math/curfit/cvacpts.gx
math/curfit/cvchomat.gx
math/curfit/cvfree.gx
math/curfit/cvinit.gx

From Davis, September 18, 1990

Changed the int calls in cvrestore.gx to nint calls. This is a totally
safe way to do the conversion from double precision to integer
quantities in the curfit package and removes any potential precision
problems for task which must read the curfit structure back from a
text database file.

From Davis, July 14, 1988:

The calling sequence for the cverrors routine as been changed to include
an npts argument. This edition removesd the possibility for error when
points have been rejected by setting w[i] = 0.

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From Davis, April 30, 1986:

1. Several bugs involving double precision constants in the double precision
version of curfit detected on the SUN have been fixed.

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From Davis, March 13, 1986:

1. A double precision version of CURFIT has been installed in IRAF. The entry
points for the double precision version are identical to those of the real
version with the addition of a preceeding d (e.g. cveval and dcveval). All
internal arithmetic is done in double and the data is entered in double.

2. A user function facility has been added to CURFIT. The user may enter
any linear function in the following manner.

	extern func

	...

	call cvinit (cv, USERFNC, nterms, xmin, xmax)
	call cvuser (cv, func)
	call cvfit (cv, x, y, w, npts, WTS_USER, ier)
	call cvvector (cv, x, yfit, npts)
	call cvfree (cv)

	...

The user function must have the following form.

	procedure func (x, nterms, k1, k2, basis)

where

	real	x		x value
	int	nterms		number of basis functions
	real	k1, k2		optional normalization parameters
	real	basis[ARB]	computed basis functions

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.endhelp