#======================================================================
#                    . I S O P L E T H . S I G M A 2 
#                    doc: Tue Dec 13 21:50:18 2005
#                    dlm: Wed Dec 14 09:11:01 2005
#                    (c) 2005 A.M. Thurnherr
#                    uE-Info: 19 26 NIL 0 0 72 2 2 4 NIL ofnI
#======================================================================

# HISTORY:
#	Dec 13, 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,$y,0,2000)
						  : sigma($y,$x,0,2000)
}

1;