.help gssub Aug85 "Gsurfit Package"
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NAME
gssub -- subtract surface 1 from surface 2
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SYNOPSIS
gssub (sf1, sf2, sf3)

.nf
pointer	sf1		# first surface descriptor
pointer	sf2		# second surface descriptor
pointer	sf3		# resultant surface descriptor
.fi
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ARGUMENTS
.ls sf1    
Pointer to the first surface descriptor.
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.ls sf2   
Pointer to the second surface descriptor.
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.ls sf3    
Pointer to the resultant surface descriptor.
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DESCRIPTION
The coefficients of surface 2 are subtracted from surface 1. GSSUB checks
that the surface_types are the same and that the fits are normalized over
the same range of data.
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NOTES
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SEE ALSO
gscopy, gsadd
.endhelp