#======================================================================
#                    . 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;