From 71a740c16118b283ff7b7fe253ac3c68eed2d64c Mon Sep 17 00:00:00 2001
From: John Hewson <jchewso@sandia.gov>
Date: Sun, 15 Nov 2009 04:49:05 +0000
Subject: [PATCH] Catching MargulesVPSSTP up to prior commit (nomenclature
 change)

---
 Cantera/src/thermo/MargulesVPSSTP.cpp | 14 +++++++-------
 Cantera/src/thermo/MargulesVPSSTP.h   | 23 ++++++++++++++---------
 2 files changed, 21 insertions(+), 16 deletions(-)

diff --git a/Cantera/src/thermo/MargulesVPSSTP.cpp b/Cantera/src/thermo/MargulesVPSSTP.cpp
index 4a9387970..21af0007d 100644
--- a/Cantera/src/thermo/MargulesVPSSTP.cpp
+++ b/Cantera/src/thermo/MargulesVPSSTP.cpp
@@ -656,12 +656,12 @@ namespace Cantera {
    *
    *   he = X_A X_B(B + C(X_A - X_B))
    */
-  void MargulesVPSSTP::s_update_dlnActCoeff_dlnX() const {
+  void MargulesVPSSTP::s_update_dlnActCoeff_dlnC() const {
     int iA, iB;
     doublereal XA, XB, g0 , g1;
     doublereal T = temperature();
 
-    fvo_zero_dbl_1(dlnActCoeffdlnX_Scaled_, m_kk);
+    fvo_zero_dbl_1(dlnActCoeffdlnC_Scaled_, m_kk);
 
     doublereal RT = GasConstant * T;
     for (int i = 0; i <  numBinaryInteractions_; i++) {
@@ -674,17 +674,17 @@ namespace Cantera {
       g0 = (m_HE_b_ij[i] - T * m_SE_b_ij[i]) / RT ;
       g1 = (m_HE_c_ij[i] - T * m_SE_c_ij[i]) / RT;
       
-      dlnActCoeffdlnX_Scaled_[iA] += XA * ( ( - 2.0 + 2.0 * XA ) * g0
+      dlnActCoeffdlnC_Scaled_[iA] += XA * ( ( - 2.0 + 2.0 * XA ) * g0
 					    + ( - 4.0 + 10.0 * XA - 6.0 * XA*XA ) * g1 ) ;
-      dlnActCoeffdlnX_Scaled_[iB] += XB * ( ( - 2.0 + 2.0 * XB ) * g0
+      dlnActCoeffdlnC_Scaled_[iB] += XB * ( ( - 2.0 + 2.0 * XB ) * g0
 					    + (   2.0 -  8.0 * XB + 6.0 * XB*XB ) * g1 ) ;
     }
   }
 
-  void MargulesVPSSTP::getdlnActCoeffdlnX(doublereal *dlnActCoeffdlnX) const {
-    s_update_dlnActCoeff_dlnX();
+  void MargulesVPSSTP::getdlnActCoeffdlnC(doublereal *dlnActCoeffdlnC) const {
+    s_update_dlnActCoeff_dlnC();
     for (int k = 0; k < m_kk; k++) {
-      dlnActCoeffdlnX[k] = dlnActCoeffdlnX_Scaled_[k];
+      dlnActCoeffdlnC[k] = dlnActCoeffdlnC_Scaled_[k];
     }
   }
 
diff --git a/Cantera/src/thermo/MargulesVPSSTP.h b/Cantera/src/thermo/MargulesVPSSTP.h
index e3c8ad67a..e9044b1bb 100644
--- a/Cantera/src/thermo/MargulesVPSSTP.h
+++ b/Cantera/src/thermo/MargulesVPSSTP.h
@@ -593,21 +593,26 @@ namespace Cantera {
     virtual void getdlnActCoeffdT(doublereal *dlnActCoeffdT) const;
 
  
-    //! Get the array of derivatives of the log activity coefficients
-    //! with respect to the log mole fractions
+    //! Get the array of log concentration-like derivatives of the 
+    //! log activity coefficients
     /*!
-     * This function is a virtual class, but it first appears in
-     * GibbsExcessVPSSTP class and derived classes.
-     * Output vector of log(mole fraction) derivatives of the 
-     * log Activity Coefficients.
+     * This function is a virtual method.  For ideal mixtures 
+     * (unity activity coefficients), this can return zero.  
+     * Implementations should take the derivative of the 
+     * logarithm of the activity coefficient with respect to the 
+     * logarithm of the concentration-like variable (i.e. mole fraction,
+     * molality, etc.) that represents the standard state.  
+     * This quantity is to be used in conjunction with derivatives of 
+     * that concentration-like variable when the derivative of the chemical 
+     * potential is taken.  
      *
      *  units = dimensionless
      *
-     * @param dlnActCoeffdlnX    Output vector of log(mole fraction)  
+     * @param dlnActCoeffdlnC    Output vector of log(mole fraction)  
      *                 derivatives of the log Activity Coefficients.
      *                 length = m_kk
      */
-    virtual void getdlnActCoeffdlnX(doublereal *dlnActCoeffdlnX) const;
+    virtual void getdlnActCoeffdlnC(doublereal *dlnActCoeffdlnC) const;
 
  
     //@}
@@ -756,7 +761,7 @@ namespace Cantera {
      * derivative of the natural logarithm of the activity coefficients
      * wrt logarithm of the mole fractions.
      */
-    void s_update_dlnActCoeff_dlnX() const;
+    void s_update_dlnActCoeff_dlnC() const;
 
 
   private: