solverPerformance: added a "max" function

Improves the handling of residuals from the segregated solution of vectors and tensors.

src/OpenFOAM/matrices/lduMatrix/lduMatrix/lduMatrix.H

@@ -210,6 +210,16 @@ public:
             void print() const;
 
 
+        // Friend functions
+
+            //- Return the element-wise maximum of two solverPerformances
+            friend solverPerformance max
+            (
+                const solverPerformance&,
+                const solverPerformance&
+            );
+
+
         // Ostream Operator
 
             friend Ostream& operator<<(Ostream&, const solverPerformance&);

src/OpenFOAM/matrices/lduMatrix/lduMatrix/lduMatrixTests.C

@@ -118,6 +118,25 @@ void Foam::lduMatrix::solverPerformance::print() const
 }
 
 
+Foam::lduMatrix::solverPerformance::solverPerformance Foam::max
+(
+    const lduMatrix::solverPerformance& sp1,
+    const lduMatrix::solverPerformance& sp2
+)
+{
+    return lduMatrix::solverPerformance
+    (
+        sp1.solverName(),
+        sp1.fieldName_,
+        max(sp1.initialResidual(), sp2.initialResidual()),
+        max(sp1.finalResidual(), sp2.finalResidual()),
+        max(sp1.nIterations(), sp2.nIterations()),
+        sp1.converged() && sp2.converged(),
+        sp1.singular() || sp2.singular()
+    );
+}
+
+
 Foam::Ostream& Foam::operator<<
 (
     Ostream& os,
@@ -137,4 +156,5 @@ Foam::Ostream& Foam::operator<<
     return os;
 }
 
+
 // ************************************************************************* //

src/finiteVolume/fvMatrices/fvMatrix/fvMatrixSolve.C

@@ -149,14 +149,7 @@ Foam::lduMatrix::solverPerformance Foam::fvMatrix<Type>::solve
 
         solverPerf.print();
 
-        if
-        (
-            solverPerf.initialResidual() > solverPerfVec.initialResidual()
-         && !solverPerf.singular()
-        )
-        {
-            solverPerfVec = solverPerf;
-        }
+        solverPerfVec = max(solverPerfVec, solverPerf);
 
         psi.internalField().replace(cmpt, psiCmpt);
         diag() = saveDiag;