.help islfit Apr85 "Surfit Package"
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NAME
islfit -- fit a surface grid line
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SYNOPSIS
include <math/surfit.h>

islfit (sf, cols, lineno, z, w, npts, wtflag, ier)

.nf
pointer	sf		# surface grid descriptor
real	cols[npts]	# array of column numbers, 1 <= cols[i] <= ncols
int	lineno		# number of surface grid line to be added
real	z[npts]		# data values
real	w[npts]		# weight array
int	npts		# number of data points, npts <= ncols
int	wtflag		# type of weighting
int	ier		# error code
.fi
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ARGUMENTS
.ls sf    
Pointer to the surface grid descriptor structure.
.le
.ls cols
The column numbers of surface grid points to be added to the dataset.
.le
.ls lineno
The line number of the surface grid line to be added to the dataset.
.le
.ls z      
Array of data values.
.le
.ls w
Array of weights.
.le
.ls npts
Number of data points.
.le
.ls wtflag
Type of weighting. The options are SF_USER and SF_UNIFORM. If wtflag =
SF_USER individual weights for each data point are supplied by the calling
program and points with zero-valued weights are not included in the fit.
If wtflag = SF_UNIFORM, all weights are assigned values of 1.
.le
.ls ier     
Error code for the fit. The options are OK, SINGULAR and NO_DEG_FREEDOM.
If ier = SINGULAR, the numerical routines will compute a solution but one
or more of the coefficients will be zero. If ier = NO_DEG_FREEDOM there
were too few data points to solve the matrix equations and the routine
returns without fitting the data.
.le
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DESCRIPTION
ISLFIT zeroes the appropriate arrays and vectors,
computes the contribution of each data point to the normal equations
in x and accumulates it into the appropriate array and vector elements.  The
x coefficients are stored for later use by ISSOLVE.
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NOTES
Checking for out of bounds col values and INDEF values pixels is the
responsibility of the user.
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SEE ALSO
isinit, islrefit, islaccum, islsolve, islzero, issolve, isfree
.endhelp