norm.H

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    Copyright (C) 2022 OpenCFD Ltd.
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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
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    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/>.
 
Class
    Foam::functionObjects::norm
 
Group
    grpFieldFunctionObjects
 
Description
    Normalises an input field with a chosen norm, and outputs a new normalised
    field.
 
    Operands:
    \table
      Operand  | Type                               | Location
      input    | {vol,surface,polySurface}TypeField | <time>/inputField
      output file  | -                              | -
      output field | {vol,surface,polySurface}TypeField | <time>/outputField
    \endtable
 
    where \c Type can be one of:
        \c Scalar, \c Vector, \c SphericalTensor, \c SymmTensor, or \c Tensor.
 
Usage
    Minimal example by using \c system/controlDict.functions:
    \verbatim
    normFO
    {
        // Mandatory entries
        type            norm;
        libs            (fieldFunctionObjects);
        field           <word>;
        norm            <word>;
 
        // Conditional entries
 
            // when norm == Lp
            p               <scalar>;
 
            // when norm == composite
            divisor         <Function1<scalar>>;
 
            // when norm == divisorField
            divisorField    <word>;
 
        // Inherited entries
        ...
    }
    \endverbatim
 
    where the entries mean:
    \table
      Property | Description                        | Type | Reqd | Deflt
      type     | Type name: norm                    | word | yes  | -
      libs     | Library name: fieldFunctionObjects | word | yes  | -
      field    | Name of the operand field          | word | yes  | -
      norm     | Name of normalisation operation    | word | yes  | -
      p        | Norm exponent for the p-norm       | scalar | cndtnl | -
      divisor  | Norm divisor for the composite norm        <!--
               -->                     | Function1<scalar> | cndtnl | -
      divisorField | Divisor scalar field for the field norm <!--
               -->                                  | word | cndtnl | -
    \endtable
 
    Options for the \c norm entry:
    \verbatim
      L1            | L1/Taxicab norm
      L2            | L2/Euclidean norm
      Lp            | p norm
      max           | Maximum norm
      composite     | Composite norm comprising Function1 divisor
      divisorField  | Normalise by a given field
    \endverbatim
 
    The inherited entries are elaborated in:
      - \link fieldExpression.H \endlink
      - \link Function1.H \endlink
 
 
    The normalisations are held according to the following expressions:
 
    - \c L1:
 
    \f[
        \mathbf{y} = \frac{\mathbf{x}}{\Sigma_{i=1}^n |x_i|}
    \f]
 
    - \c L2:
 
    \f[
        \mathbf{y} = \frac{\mathbf{x}}{\sqrt{x_1^2 + ... + x_n^2}}
    \f]
 
    - \c Lp:
 
    \f[
        \mathbf{y} = \frac{\mathbf{x}}{(\Sigma_{i=1}^n |x_i|^p)^{1/p}}
    \f]
 
    - \c max:
 
    \f[
        \mathbf{y} = \frac{\mathbf{x}}{max|x_i|}
    \f]
 
    - \c composite:
 
    \f[
        \mathbf{y} = \frac{\mathbf{x}}{f(t)}
    \f]
 
    - \c divisorField:
 
    \f[
        \mathbf{y} = \frac{\mathbf{x}}{\mathbf{z}}
    \f]
 
Note
  - Divisor quantity is perturbed by \c SMALL value to prevent any divisions
    by zero irrespective of whether the quantity is close to zero or not.
 
SourceFiles
    norm.C
    normImpl.C
 
\*---------------------------------------------------------------------------*/
 
#ifndef Foam_functionObjects_norm_H
#define Foam_functionObjects_norm_H
 
#include "fieldExpression.H"
#include "Function1.H"
#include "polySurfaceFields.H"
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
namespace Foam
{
namespace functionObjects
{
 
/*---------------------------------------------------------------------------*\
                            Class norm Declaration
\*---------------------------------------------------------------------------*/
 
class norm
:
    public fieldExpression
{
    // Private Enumerations
 
        //- Options for the norm algorithm
        enum normType : char
        {
            L1,             
            L2,             
            LP,             
            MAX,            
            COMPOSITE,      
            FIELD           
        };
 
        //- Names for normType
        static const Enum<normType> normTypeNames;
 
 
    // Private Data
 
        //- Norm algorithm
        enum normType norm_;
 
        //- Norm divisor for the composite norm
        autoPtr<Function1<scalar>> divisorPtr_;
 
        //- Divisor scalar field for the field norm
        word divisorFieldName_;
 
        //- Norm exponent for the p norm
        scalar p_;
 
 
    // Private Member Functions
 
        //- Calculate the chosen norm of the field and register the result
        template<class Type>
        bool calcNorm();
 
        //- Return the chosen norm of the field
        template<class GeoFieldType>
        tmp<GeoFieldType> calcNormType();
 
        //- Return the divisor volScalarField
        template<class Type>
        tmp<volScalarField> fieldNorm
        (
            const GeometricField<Type, fvPatchField, volMesh>&
        );
 
        //- Return the divisor surfaceScalarField
        template<class Type>
        tmp<surfaceScalarField> fieldNorm
        (
            const GeometricField<Type, fvsPatchField, surfaceMesh>&
        );
 
        //- Return the divisor polySurfaceScalarField
        template<class Type>
        tmp<polySurfaceScalarField> fieldNorm
        (
            const DimensionedField<Type, polySurfaceGeoMesh>&
        );
 
        //- Calculate the chosen norm of the field and return true if successful
        virtual bool calc();
 
 
public:
 
    //- Runtime type information
    TypeName("norm");
 
 
    // Constructors
 
        //- Construct from name, Time and dictionary
        norm
        (
            const word& name,
            const Time& runTime,
            const dictionary& dict
        );
 
        //- No copy construct
        norm(const norm&) = delete;
 
        //- No copy assignment
        void operator=(const norm&) = delete;
 
 
    //- Destructor
    virtual ~norm() = default;
 
 
    // Member Functions
 
        //- Read the function-object dictionary
        virtual bool read(const dictionary& dict);
};
 
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
} // End namespace functionObjects
} // End namespace Foam
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
#endif
 
// ************************************************************************* //