From 79b4fa45a15a511d035e1fbb14b4e0736f7a7870 Mon Sep 17 00:00:00 2001
From: Lew Rossman <LRossman@outlook.com>
Date: Fri, 5 Aug 2022 16:59:32 -0400
Subject: [PATCH] Update hydcoeffs.c

Only an Active PSV needs to preserve connectivity.
---
 src/hydcoeffs.c | 24 ++----------------------
 1 file changed, 2 insertions(+), 22 deletions(-)

diff --git a/src/hydcoeffs.c b/src/hydcoeffs.c
index b4ba6cd..83b2dc3 100644
--- a/src/hydcoeffs.c
+++ b/src/hydcoeffs.c
@@ -62,7 +62,6 @@ static void    tcvcoeff(Project *pr, int k);
 static void    prvcoeff(Project *pr, int k, int n1, int n2);
 static void    psvcoeff(Project *pr, int k, int n1, int n2);
 static void    fcvcoeff(Project *pr, int k, int n1, int n2);
-static void    valveconnectcoeffs(Project *pr, int k, int n1, int n2);
 
 
 void  resistcoeff(Project *pr, int k)
@@ -318,11 +317,9 @@ void  valvecoeffs(Project *pr)
         {
         case PRV:
             prvcoeff(pr, k, n1, n2);
-            valveconnectcoeffs(pr, k, n1, n2);
             break;
         case PSV:
             psvcoeff(pr, k, n1, n2);
-            valveconnectcoeffs(pr, k, n1, n2);
             break;
         case FCV:
             fcvcoeff(pr, k, n1, n2);
@@ -332,25 +329,6 @@ void  valvecoeffs(Project *pr)
     }
 }
 
-void valveconnectcoeffs(Project *pr, int k, int n1, int n2)
-/*
-**--------------------------------------------------------------
-**   Input:   k    = valve's link index
-**            n1   = upstream node of valve
-**            n2   = downstream node of valve
-**   Output:  none
-**   Purpose: insures that the off-diagonals in the rows for a
-**            PRV/PSV are non-zero to preserve connectivity.
-**--------------------------------------------------------------
-*/
-{
-    Smatrix *sm =  &pr->hydraul.smatrix;
-    double p = 1.0 / CBIG;
-    sm->Aij[sm->Ndx[k]] -= p;
-    sm->Aii[sm->Row[n1]] += p;
-    sm->Aii[sm->Row[n2]] += p;
-}    
-
 
 void  emittercoeffs(Project *pr)
 /*
@@ -1057,6 +1035,8 @@ void  psvcoeff(Project *pr, int k, int n1, int n2)
         {
             sm->F[j] += hyd->Xflow[n1];
         }
+        sm->Aij[sm->Ndx[k]] -= 1.0 / CBIG;             // Preserve connectivity
+        sm->Aii[j] += 1.0 / CBIG;
         return;
     }