ENH: lerp for patch/neighbour weights

src/finiteArea/fields/faPatchFields/basic/coupled/coupledFaPatchField.C

@@ -130,8 +130,12 @@ void Foam::coupledFaPatchField<Type>::evaluate(const Pstream::commsTypes)
 {
     Field<Type>::operator=
     (
-        this->patch().weights()*this->patchInternalField()
+        lerp
-      + (1.0 - this->patch().weights())*patchNeighbourField()
+        (
+            this->patchNeighbourField(),
+            this->patchInternalField(),
+            this->patch().weights()
+        )
     );
 }
 

src/finiteArea/interpolation/edgeInterpolation/schemes/Gamma/Gamma.H

@@ -112,7 +112,7 @@ public:
         scalar phict = 1 - 0.5*gradf/gradcf;
         scalar limiter = min(max(phict/k_, 0), 1);
 
-        return limiter*cdWeight + (1 - limiter)*udWeight;
+        return lerp(udWeight, cdWeight, limiter);
     }
 };
 

src/finiteVolume/fields/fvPatchFields/basic/coupled/coupledFvPatchField.C

@@ -139,8 +139,12 @@ void Foam::coupledFvPatchField<Type>::evaluate(const Pstream::commsTypes)
 
     Field<Type>::operator=
     (
-        this->patch().weights()*this->patchInternalField()
+        lerp
-      + (1.0 - this->patch().weights())*this->patchNeighbourField()
+        (
+            this->patchNeighbourField(),
+            this->patchInternalField(),
+            this->patch().weights()
+        )
     );
 
     fvPatchField<Type>::evaluate();

src/finiteVolume/interpolation/surfaceInterpolation/surfaceInterpolationScheme/surfaceInterpolationScheme.C

@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2019-2021 OpenCFD Ltd.
+    Copyright (C) 2019-2023 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -264,6 +264,9 @@ Foam::surfaceInterpolationScheme<Type>::dotInterpolate
 
     for (label fi=0; fi<P.size(); fi++)
     {
+        // Same as:
+        // sfi[fi] = Sfi[fi] & lerp(vfi[N[fi]], vfi[P[fi]], lambda[fi]);
+        // but maybe the compiler notices the fused multiply add form
         sfi[fi] = Sfi[fi] & (lambda[fi]*(vfi[P[fi]] - vfi[N[fi]]) + vfi[N[fi]]);
     }
 
@@ -282,9 +285,11 @@ Foam::surfaceInterpolationScheme<Type>::dotInterpolate
         {
             psf =
                 pSf
-              & (
+              & lerp
-                    pLambda*vf.boundaryField()[pi].patchInternalField()
+                (
-                  + (1.0 - pLambda)*vf.boundaryField()[pi].patchNeighbourField()
+                    vf.boundaryField()[pi].patchNeighbourField(),
+                    vf.boundaryField()[pi].patchInternalField(),
+                    pLambda
                 );
         }
         else

src/sampling/surface/isoSurface/isoSurfacePointTemplates.C

@@ -111,11 +111,12 @@ Foam::isoSurfacePoint::adaptPatchFields
                 sliceFldBf[patchi]
             );
 
-            const scalarField& w = mesh.weights().boundaryField()[patchi];
+            tmp<Field<Type>> f = lerp
-
+            (
-            tmp<Field<Type>> f =
+                pfld.patchNeighbourField(),
-                w*pfld.patchInternalField()
+                pfld.patchInternalField(),
-              + (1.0-w)*pfld.patchNeighbourField();
+                mesh.weights().boundaryField()[patchi]
+            );
 
             bitSet isCollocated
             (