Gabriele Cosmo
106 lines
4.5 KiB
C++
106 lines
4.5 KiB
C++
//
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// ********************************************************************
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// * License and Disclaimer *
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// * *
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// * The Geant4 software is copyright of the Copyright Holders of *
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// * the Geant4 Collaboration. It is provided under the terms and *
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// * conditions of the Geant4 Software License, included in the file *
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// * LICENSE and available at http://cern.ch/geant4/license . These *
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// * include a list of copyright holders. *
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// * *
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// * Neither the authors of this software system, nor their employing *
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// * institutes,nor the agencies providing financial support for this *
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// * work make any representation or warranty, express or implied, *
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// * regarding this software system or assume any liability for its *
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// * use. Please see the license in the file LICENSE and URL above *
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// * for the full disclaimer and the limitation of liability. *
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// * *
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// * This code implementation is the result of the scientific and *
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// * technical work of the GEANT4 collaboration. *
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// * By using, copying, modifying or distributing the software (or *
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// * any work based on the software) you agree to acknowledge its *
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// * use in resulting scientific publications, and indicate your *
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// * acceptance of all terms of the Geant4 Software license. *
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// ********************************************************************
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//
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//
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// $Id: G4Field.hh,v 1.10 2006/06/29 18:22:13 gunter Exp $
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// GEANT4 tag $Name: geant4-09-01 $
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//
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//
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// class G4Field
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//
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// Class description:
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//
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// Abstract class for any kind of Field.
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// It allows any kind of field (vector, scalar, tensor and any set of them)
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// to be defined by implementing the inquiry function interface.
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//
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// The key method is GetFieldValue( const double Point[4],
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// ************* double *fieldArr )
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// Given an input position/time vector 'Point',
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// this method must return the value of the field in "fieldArr".
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//
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// A field must also specify whether it changes a track's energy:
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// DoesFieldChangeEnergy()
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// *********************
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// A field must co-work with a corresponding Equation of Motion, to
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// enable the integration of a particle's position, momentum and, optionally,
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// spin. For this a field and its equation of motion must follow the
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// same convention for the order of field components in the array "fieldArr"
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// -------------------------------------------------------------------
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// History:
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// - Created: John Apostolakis, 10.03.1997
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// - Modified:
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// V. Grichine 8 Nov 2001: Extended "Point" arg to [4] array to add time
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// J. Apostolakis 5 Nov 2003: Added virtual method DoesFieldChangeEnergy()
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// J. Apostolakis 31 Aug 2004: Information on convention for components
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// -------------------------------------------------------------------
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#ifndef G4FIELD_HH
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#define G4FIELD_HH
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#include "G4Types.hh"
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class G4Field
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{
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public: // with description
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virtual void GetFieldValue( const double Point[4],
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double *fieldArr ) const = 0;
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// Given the position time vector 'Point',
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// return the value of the field in the array fieldArr.
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// Notes:
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// 1) The 'Point' vector has the following structure:
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// Point[0] is x ( position, in Geant4 units )
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// Point[1] is y
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// Point[2] is z
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// Point[3] is t ( time, in Geant4 units )
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// 2) The convention for the components of the field
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// array 'fieldArr' are determined by the type of field.
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// See for example the class G4ElectroMagneticField.
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G4Field(){;}
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virtual ~G4Field(){;}
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inline G4Field& operator = (const G4Field &p);
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// A field signature function that can be used to insure
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// that the Equation of motion object and the G4Field object
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// have the same "field signature"?
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virtual G4bool DoesFieldChangeEnergy() const= 0 ;
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// Each type/class of field should respond this accordingly
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// For example:
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// - an electric field should return "true"
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// - a pure magnetic field should return "false"
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};
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inline G4Field& G4Field::operator = (const G4Field &p)
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{
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if (&p != this) { *this = p; }
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return *this;
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}
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#endif /* G4FIELD_HH */
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