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

#                    . I S O P L E T H . S I G M A 0 

#                    doc: Tue Dec 13 21:50:18 2005

#                    dlm: Wed Dec 14 09:40:50 2005

#                    (c) 2005 A.M. Thurnherr

#                    uE-Info: 44 43 NIL 0 0 72 2 2 4 NIL ofnI

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

# HISTORY:

#	Dec 14, 2005: - created

# NOTES:

#	- assumes T/S fields to be called 'temp' and 'salin'

require "$ANTS/libEOS83.pl";				# load equation of state

unless (defined($P{ITS})) {

	&antsInfo("using default %ITS=90");

	&antsAddParams(ITS,90);

}

sub yfield_isopleth($)						# return y-field based on x-field

{

	my($xf) = @_;

	return $xf eq 'salin' ? 'temp' : 'salin';

}

sub bracket_isopleth($$$$)					# heuristically bracket y field

{

	my($xf,$xv,$iv,$prev_y) = @_;

	if ($xf eq 'salin') {

		return (-10,30);

	} else {

		return (34,37);

	}

}

sub eval_isopleth($$$)						# evaluate function for isopleth

{

	my($xf,$x,$y) = @_;

	return $xf eq 'salin' ? sigma($x,$y,0,0)

						  : sigma($y,$x,0,0)

}

1;