ENH: improvements to SubList and SubField

- SubField and SubList assign from zero
- SubField +=, -=, *=, /= operators

- SubList construct from UList (as per SubField)

  Note: constructing an anonymous SubField or SubList with a single
  parameter should use '{} instead of '()' to avoid compiler
  ambiguities.

applications/test/SubField/Make/files

@@ -0,0 +1,3 @@
+Test-SubField.C
+
+EXE = $(FOAM_USER_APPBIN)/Test-SubField

applications/test/SubField/Make/options

@@ -0,0 +1,2 @@
+/* EXE_INC = */
+/* EXE_LIBS = */

applications/test/SubField/Test-SubField.C

@@ -0,0 +1,94 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | Copyright (C) 2019 OpenCFD Ltd.
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+License
+    This file is part of OpenFOAM.
+
+    OpenFOAM is free software: you can redistribute it and/or modify it
+    under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
+    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+    for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
+
+Application
+    Test-SubField
+
+Description
+    Simple tests on SubList, SubField
+
+\*---------------------------------------------------------------------------*/
+
+#include "OSspecific.H"
+#include "argList.H"
+
+#include "scalarField.H"
+#include "SubField.H"
+#include "labelRange.H"
+#include <numeric>
+
+using namespace Foam;
+
+template<class T>
+void print(const UList<T>& list)
+{
+    Info<< flatOutput(list) << nl;
+}
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+//  Main program:
+
+int main(int argc, char *argv[])
+{
+    argList::noParallel();
+    argList::noFunctionObjects();
+
+    {
+        List<scalar> ident(25);
+        std::iota(ident.begin(), ident.end(), 0);
+
+        print(ident);
+
+        SubList<scalar>(ident, 10) = -10;
+        print(ident);
+
+        SubField<scalar>(ident, 10) = 10;
+        print(ident);
+
+        SubField<scalar>(ident, 10) += 10;
+        print(ident);
+
+        SubField<scalar>{ident, 10, 10} *= 5;
+        print(ident);
+
+
+        // NOTE: Need {} instead of ()
+        // SubList<scalar>(ident) = 100;
+
+        // GCC
+        // error: conflicting declaration 'Foam::SubList<double> ident'
+
+        // CLANG
+        // warning: parentheses were disambiguated as redundant parentheses
+        // around declaration of variable named 'ident' [-Wvexing-parse]
+
+        SubList<scalar>{ident} = 100;
+        print(ident);
+    }
+
+    Info << "\nEnd\n";
+    return 0;
+}
+
+// ************************************************************************* //

src/OpenFOAM/containers/Lists/SubList/SubList.H

@@ -77,6 +77,9 @@ public:
 
     // Constructors
 
+        //- Construct from UList, the entire size
+        inline explicit SubList(const UList<T>& list);
+
         //- Construct from UList and sub-list size, start at 0
         inline SubList
         (
@@ -112,17 +115,20 @@ public:
 
     // Member Operators
 
-        //- Allow cast to a const List<T>&
+        //- Allow cast to a const List\<T\>&
         inline operator const Foam::List<T>&() const;
 
-        //- Assignment of all entries to the given sub-list
+        //- Copy assign entries from given sub-list
         inline void operator=(const SubList<T>& list);
 
-        //- Assignment of all entries to the given list
+        //- Copy assign entries to the given list
         inline void operator=(const UList<T>& list);
 
-        //- Assignment of all entries to the given value
+        //- Assign all entries to the given value
         inline void operator=(const T& val);
+
+        //- Assign all entries to zero
+        inline void operator=(const zero);
 };
 
 

src/OpenFOAM/containers/Lists/SubList/SubListI.H

@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
-    \\  /    A nd           | Copyright (C) 2017 OpenCFD Ltd.
+    \\  /    A nd           | Copyright (C) 2017-2019 OpenCFD Ltd.
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
                             | Copyright (C) 2011-2016 OpenFOAM Foundation
@@ -27,6 +27,16 @@ License
 
 // * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
 
+template<class T>
+inline Foam::SubList<T>::SubList
+(
+    const UList<T>& list
+)
+:
+    UList<T>(list.v_, list.size())
+{}
+
+
 template<class T>
 inline Foam::SubList<T>::SubList
 (
@@ -131,4 +141,11 @@ inline void Foam::SubList<T>::operator=(const T& val)
 }
 
 
+template<class T>
+inline void Foam::SubList<T>::operator=(const zero)
+{
+    UList<T>::operator=(Zero);
+}
+
+
 // ************************************************************************* //

src/OpenFOAM/fields/Fields/Field/Field.H

@@ -203,8 +203,8 @@ public:
             const bool applyFlip = true
         );
 
-        //- Construct by mapping from the given tmp field. Supplied uniform
-        //- value for unmapped items
+        //- Construct by mapping from the given tmp field.
+        //- Uses supplied uniform value for unmapped items
         Field
         (
             const tmp<Field<Type>>& tmapF,
@@ -213,8 +213,8 @@ public:
             const bool applyFlip = true
         );
 
-        //- Construct by mapping from the given tmp field. Supplied values
-        //- for unmapped items
+        //- Construct by mapping from the given tmp field.
+        //- Uses supplied values for unmapped items
         Field
         (
             const tmp<Field<Type>>& tmapF,
@@ -245,7 +245,7 @@ public:
         }
 
         //- Return a pointer to a new calculatedFvPatchFieldField created on
-        //  freestore without setting patchField values
+        //- freestore without setting patchField values
         template<class Type2>
         static tmp<Field<Type>> NewCalculatedType(const Field<Type2>& f)
         {
@@ -363,7 +363,7 @@ public:
         void writeEntry(const word& keyword, Ostream& os) const;
 
 
-    // Member operators
+    // Member Operators
 
         //- Copy assignment
         void operator=(const Field<Type>&);

src/OpenFOAM/fields/Fields/Field/SubField.H

@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
-    \\  /    A nd           | Copyright (C) 2018 OpenCFD Ltd.
+    \\  /    A nd           | Copyright (C) 2018-2019 OpenCFD Ltd.
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
                             | Copyright (C) 2011-2016 OpenFOAM Foundation
@@ -73,20 +73,23 @@ public:
 
     // Constructors
 
-        //- Copy construct from a SubList
+        //- Copy construct (shallow copy)
+        inline SubField(const SubField<Type>& sfield);
+
+        //- Copy construct from SubList
         inline SubField(const SubList<Type>& list);
 
-        //- Construct from a UList, the entire size
+        //- Construct from UList, the entire size
         inline explicit SubField(const UList<Type>& list);
 
-        //- Construct from a UList with a given sub-list size, start at 0
+        //- Construct from UList with a given sub-list size, start at 0
         inline SubField
         (
             const UList<Type>& list,
             const label subSize
         );
 
-        //- Construct from a UList with a given size and start index
+        //- Construct from UList with a given size and start index
         inline SubField
         (
             const UList<Type>& list,
@@ -111,9 +114,6 @@ public:
             const UList<Type>& list
         );
 
-        //- Copy construct
-        inline SubField(const SubField<Type>& sfield);
-
 
     // Member Functions
 
@@ -127,7 +127,10 @@ public:
         tmp<Field<Type>> T() const;
 
 
-    // Member operators
+    // Member Operators
+
+        //- Allow cast to a const Field\<Type\>&
+        inline operator const Foam::Field<Type>&() const;
 
         //- Copy assign via UList operator. Takes linear time.
         inline void operator=(const SubField<Type>&);
@@ -135,12 +138,27 @@ public:
         //- Copy assign via UList operator. Takes linear time.
         inline void operator=(const Field<Type>&);
 
+        //- Assign all entries to the given value
+        inline void operator=(const Type& val);
+
+        //- Assign all entries to zero
+        inline void operator=(const zero);
+
         //- Copy assign via UList operator. Takes linear time.
         template<class Form, direction Ncmpts>
-        inline void operator=(const VectorSpace<Form, Type, Ncmpts>&);
+        inline void operator=(const VectorSpace<Form, Type, Ncmpts>& rhs);
 
-        //- Allow cast to a const Field\<Type\>&
-        inline operator const Field<Type>&() const;
+        //- Add value to each entry
+        inline void operator+=(const Type& val);
+
+        //- Subtract value from each entry
+        inline void operator-=(const Type& val);
+
+        //- Multiply each entry by value
+        inline void operator*=(const scalar& s);
+
+        //- Divide each entry by value
+        inline void operator/=(const scalar& s);
 };
 
 

src/OpenFOAM/fields/Fields/Field/SubFieldI.H

@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
-    \\  /    A nd           |
+    \\  /    A nd           | Copyright (C) 2017-2019 OpenCFD Ltd.
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
                             | Copyright (C) 2011-2016 OpenFOAM Foundation
@@ -27,6 +27,16 @@ License
 
 // * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
 
+template<class Type>
+inline Foam::SubField<Type>::SubField
+(
+    const SubField<Type>& sfield
+)
+:
+    SubList<Type>(sfield)
+{}
+
+
 template<class Type>
 inline Foam::SubField<Type>::SubField
 (
@@ -92,17 +102,6 @@ inline Foam::SubField<Type>::SubField
 {}
 
 
-template<class Type>
-inline Foam::SubField<Type>::SubField
-(
-    const SubField<Type>& sfield
-)
-:
-    refCount(),
-    SubList<Type>(sfield)
-{}
-
-
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
 template<class Type>
@@ -132,6 +131,13 @@ inline Foam::tmp<Foam::Field<Type>> Foam::SubField<Type>::T() const
 
 // * * * * * * * * * * * * * * * Member Operators  * * * * * * * * * * * * * //
 
+template<class Type>
+inline Foam::SubField<Type>::operator const Foam::Field<Type>&() const
+{
+    return *reinterpret_cast<const Field<Type>*>(this);
+}
+
+
 template<class Type>
 inline void Foam::SubField<Type>::operator=(const SubField<Type>& rhs)
 {
@@ -146,6 +152,20 @@ inline void Foam::SubField<Type>::operator=(const Field<Type>& rhs)
 }
 
 
+template<class Type>
+inline void Foam::SubField<Type>::operator=(const Type& val)
+{
+    SubList<Type>::operator=(val);
+}
+
+
+template<class Type>
+inline void Foam::SubField<Type>::operator=(const zero)
+{
+    SubList<Type>::operator=(Zero);
+}
+
+
 template<class Type>
 template<class Form, Foam::direction Ncmpts>
 inline void Foam::SubField<Type>::operator=
@@ -161,9 +181,42 @@ inline void Foam::SubField<Type>::operator=
 
 
 template<class Type>
-inline Foam::SubField<Type>::operator const Foam::Field<Type>&() const
+inline void Foam::SubField<Type>::operator+=(const Type& val)
 {
-    return *reinterpret_cast<const Field<Type>*>(this);
+    for (Type& lhs : *this)
+    {
+        lhs += val;
+    }
+}
+
+
+template<class Type>
+inline void Foam::SubField<Type>::operator-=(const Type& val)
+{
+    for (Type& lhs : *this)
+    {
+        lhs -= val;
+    }
+}
+
+
+template<class Type>
+inline void Foam::SubField<Type>::operator*=(const scalar& s)
+{
+    for (Type& lhs : *this)
+    {
+        lhs *= s;
+    }
+}
+
+
+template<class Type>
+inline void Foam::SubField<Type>::operator/=(const scalar& s)
+{
+    for (Type& lhs : *this)
+    {
+        lhs /= s;
+    }
 }