From 367d1f90b019fa75403ba687bcc5667dbf042ab4 Mon Sep 17 00:00:00 2001
From: Harry Moffat <hkmoffa@sandia.gov>
Date: Sat, 2 Oct 2010 04:51:00 +0000
Subject: [PATCH] Small changes that I found improved things

---
 ext/tpx/CarbonDioxide.cpp |  3 ++-
 ext/tpx/CarbonDioxide.h   |  4 +++-
 ext/tpx/Sub.cpp           |  6 ++++++
 ext/tpx/Sub.h             | 10 ++++++----
 4 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/ext/tpx/CarbonDioxide.cpp b/ext/tpx/CarbonDioxide.cpp
index d0859aa06..5e717b53b 100755
--- a/ext/tpx/CarbonDioxide.cpp
+++ b/ext/tpx/CarbonDioxide.cpp
@@ -26,7 +26,8 @@ static const double Gamma=5.0E-6;    // [??]
 static const double u0=3.217405E5;    // [] internal energy at To
 static const double s0=2.1396056E3;    // [] entropy at To
 static const double Tp=250;            // [K] ??
-static const double Pc=7.38350E6;    // [Pa] critical pressure
+//static const double Pc=7.38350E6;    // [Pa] critical pressure
+static const double Pc=7.3817589E6;   // Adjusted to fit the actual functional form
 static const double M=44.01;        // [kg/kmol] molar density
 
 /*
diff --git a/ext/tpx/CarbonDioxide.h b/ext/tpx/CarbonDioxide.h
index ed3467616..945acf24a 100755
--- a/ext/tpx/CarbonDioxide.h
+++ b/ext/tpx/CarbonDioxide.h
@@ -17,7 +17,9 @@ namespace tpx {
 
 class CarbonDioxide : public Substance{
 public:
-    CarbonDioxide() {
+    CarbonDioxide() :
+      Substance()
+    {
       m_name="CarbonDioxide";
       m_formula="CO2";
      }
diff --git a/ext/tpx/Sub.cpp b/ext/tpx/Sub.cpp
index dda02e7ab..e1c91d172 100755
--- a/ext/tpx/Sub.cpp
+++ b/ext/tpx/Sub.cpp
@@ -398,6 +398,12 @@ namespace tpx {
             if (sat >= Pcrit()) return 0;
             psat = sat;
             T = Tsat(psat);
+	    if (T == Undef) {
+	      Err = 0;
+	      T = Tsave;
+	      Rho = Rhosave;
+	      return 0;
+	    }
 	}
 	else {
             throw TPX_Error("Substance::Lever","general error");
diff --git a/ext/tpx/Sub.h b/ext/tpx/Sub.h
index 3fd40eef8..e15106209 100755
--- a/ext/tpx/Sub.h
+++ b/ext/tpx/Sub.h
@@ -90,10 +90,12 @@ namespace tpx {
         void setStdState(double h0 = 0.0, double s0 = 0.0,
             double t0 = 298.15, double p0 = 1.01325e5) {
             Set(TP, t0, p0);
-            double hoff = h0 - h();
-            double soff = s0 - s();
-            m_entropy_offset = soff;
-            m_energy_offset = hoff;
+            double hh = h();
+            double ss = s();
+            double hoff = h0 - hh;
+            double soff = s0 - ss;
+            m_entropy_offset += soff;
+            m_energy_offset += hoff;
         }
 
         // information about a substance: