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

#                    U T I L I T I E S / P O S T _ M E R G E _ T L _ C H E C K . P L 

#                    doc: Wed Oct 12 10:23:58 2011

#                    dlm: Wed Oct 17 12:06:02 2012

#                    (c) 2011 A.M. Thurnherr

#                    uE-Info: 33 15 NIL 0 0 72 2 2 4 NIL ofnI

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

# HISTORY:

#	Oct 12, 2012: - created as an experimental time-lagging filter

#	Oct 17, 2012: - turned into this utility

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

# This code is used to verify (or improve) time lagging

#	- for each ensemble, a "narrow-band" time lagging is performed

#	  to determine the optimal scan offset

#	- time-lag window is taken from 2nd value of -w

#	- max search radius is hard-coded in $scan_offset_search_window

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

$post_merge_hook = sub {							# arguments: firstGoodEns, lastGoodEns

	my($fe,$le) = @_;

	progress("Writing optimal lags for all ensembles to $data_subdir/$out_basename.TLcheck...\n");

	my($scan_offset_search_window) = 10;

	my($ew_hwidth) =								# window half-width in ensembles

		int($length_of_timelag_windows[1]/2 / $LADCP{MEAN_DT} + 0.5);

	my(@mad,$nsamp);

	@antsNewLayout = ('ensemble','best_scan_offset','mad');

	open(STDOUT,">$data_subdir/$out_basename.TLcheck")

		|| croak("$data_subdir/$out_basename.TLcheck: $!\n");

	for (my($e)=$fe; $e<=$le; $e++) {

		next unless numberp($LADCP{ENSEMBLE}[$e]->{CTD_DEPTH});						# skip non-valid

		for (my($so)=-$scan_offset_search_window; $so<=$scan_offset_search_window; $so++) {			# find narrowband best lag

			$mad[$so + $scan_offset_search_window] = $nsamp = 0;

			for (my($i)=max($fe,$e-$ew_hwidth); $i<=min($le,$e+$ew_hwidth); $i++) {	# calc mad in window

				next unless numberp($LADCP{ENSEMBLE}[$i]->{CTD_DEPTH});

				$mad[$so + $scan_offset_search_window] +=

					abs($LADCP{ENSEMBLE}[$i]->{REFLR_W} - $CTD{W}[$LADCP{ENSEMBLE}[$i]->{CTD_SCAN}+$so]);

				$nsamp++;					

			} # for $i

			if ($nsamp > 0) {

				$mad[$so + $scan_offset_search_window] /= $nsamp;

			} else {

				$mad[$so + $scan_offset_search_window] = 9e99;

			}

		} # for $so

		my($best_so) = min_i(@mad) - $scan_offset_search_window;		

		&antsOut($e,$best_so,$mad[$best_so + $scan_offset_search_window]);

	}

	&antsOut('EOF'); open(STDOUT,'>&2');

};

1;