#======================================================================

#                    . N M I N T E R P . N A N 

#                    doc: Sun Jul  6 20:37:31 2014

#                    dlm: Sun Jul  6 20:39:26 2014

#                    (c) 2014 A.M. Thurnherr

#                    uE-Info: 67 0 NIL 0 0 72 2 2 4 NIL ofnI

#======================================================================

# filling gaps with nan [fillgaps]

# HISTORY:

#	Jul  6, 2014: - created from [.nminterp.linear]

#++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

#

# THE FOLLOWING VARIABLES MUST BE SET GLOBALLY (i.e. during loading)

#

#	$ISOpts				string of allowed options

#	$ISOptsUsage		usage information string for options

#

#++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

$ISOpts = "";

$ISOptsUsage = "";

#++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

#

# &ISUsage() 	mangle parameters (options, really)

#

#++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

sub ISUsage() {}

#+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

#

# &ISInit(f,xf)				init interpolation of field f

#       f					field number

#		xf					x field number or -1 for %RECNO

#       <ret val>           none

#

#++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

sub ISInit($$) {}

#+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

#

# &interpolate(xf,mg,f,lvr,cr)		interpolate field f

#		xf							x field or -1 for %RECNO

#		mg							max allowed x gap

#		f							field number to interpolate

#		lvr							last record with valid y val

#		cr							current record

#		<ret val>					interpolated value

#

# NB:

#	- handle f == xf

#	- return undef if interpolation cannot be carried out

#	- x VALUES MAY NOT BE MONOTONIC

#

#++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

sub interpolate($$$$$$)

{

	my($xf,$mg,$f,$lvr,$cr) = @_;

	return ($xf == $f) ? $ants_[$cr][$xf] : nan;

} # static scope

#----------------------------------------------------------------------

1;