1 files changed, 69 insertions, 0 deletions
diff --git a/Utilib/src/bounds.c b/Utilib/src/bounds.c
new file mode 100644
index 0000000..a8c8ec3
--- /dev/null
+++ b/Utilib/src/bounds.c
@@ -0,0 +1,69 @@
+/*
+freesteam - IAPWS-IF97 steam tables library
+Copyright (C) 2004-2009  John Pye
+
+This program is free software; you can redistribute it and/or
+modify it under the terms of the GNU General Public License
+as published by the Free Software Foundation; either version 2
+of the License, or (at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; if not, write to the Free Software
+Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+*//** @file
+	Functions to return SteamState objects for points on the
+	boundary of the ...
+*/
+
+#define FREESTEAM_BUILDING_LIB
+#include "bounds.h"
+
+#include "region.h"
+#include "b23.h"
+#include "zeroin.h"
+
+#include <stdlib.h>
+
+typedef struct{
+	double p, T;
+} SteamPTData;
+
+static double pT3_fn(double rho, void *user_data){
+#define D ((SteamPTData *)user_data)
+	return D->p - freesteam_region3_p_rhoT(rho, D->T);
+#undef D
+}
+
+SteamState freesteam_bound_pmax_T(double T){
+	SteamState S;
+	if(T <= REGION1_TMAX){
+		S.region = 1;
+		S.valueR.R1.p = IAPWS97_PMAX;
+		S.valueR.R1.T = T;
+	}else if(T > freesteam_region2_s_pT(IAPWS97_PMAX,freesteam_b23_T_p(IAPWS97_PMAX))){
+		S.region = 2;
+		S.valueR.R2.p = IAPWS97_PMAX;
+		S.valueR.R2.T = T;
+	}else{
+		double tol = 1e-7;
+		double sol, err = 0;
+                double lb, ub;
+		SteamPTData D = {IAPWS97_PMAX, T};
+		S.region = 3;
+		S.valueR.R3.T = T;
+		lb = 1./freesteam_region2_v_pT(freesteam_b23_p_T(T),T);
+		ub = 1./freesteam_region1_v_pT(IAPWS97_PMAX,REGION1_TMAX);
+
+		if(zeroin_solve(&pT3_fn, &D, lb, ub, tol, &sol, &err)){
+			fprintf(stderr,"%s (%s:%d): failed to solve for rho\n",__func__,__FILE__,__LINE__);
+			exit(1);
+		}
+		S.valueR.R3.rho = sol;
+	}
+	return S;
+}