BLTune.hh

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//      BLTune.hh
/*
This source file is part of G4beamline, http://g4beamline.muonsinc.com
Copyright (C) 2003,2004,2005,2006 by Tom Roberts, all rights reserved.

This program 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 2
of the License, or (at your option) any later version.

This program 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.

http://www.gnu.org/copyleft/gpl.html
*/

#ifndef BLTUNE_HH
#define BLTUNE_HH

#include <map>
#include "globals.hh"
#include "BLEvaluator.hh"


/**     class BLTune contains the general interface to tuning arguments.
 *
 *      The tune command (class BLCMDtune) will tune arguments to commands
 *      with the goal of achieving some specified measure of performance.
 *      Tuning occurs when the Tune Particle is tracked, and only those
 *      aspects of performance that can be achieved during that tracking
 *      can be tuned. The example used here is to tune the current in a
 *      genericbend so the reference particle had dxdz=0 after the magnet.
 *
 *      Tunable arguments to a command must:
 *       a) be declared with argTunable() in defineArgs()
 *       b) be referenced indirectly by each placement class of the element;
 *          that is, the placement object cannot keep a local copy, but
 *          must always reference the actual parameter variable of the Element.
 *       c) be copied using BLTune::copyTunableArg() in the element's copy
 *          constructor
 *
 *      Tunable arguments are set on either the element or place command
 *      using the usual name=expression syntax. The expression can contain
 *      the name of any enclosing tune command as a variable, and the value
 *      of the variable will always be the current value during tuning, and
 *      will be the final result after tuning is complete.
**/
class BLTune {
        static BLEvaluator eval;
        static std::map<G4double*,G4String> tuneExpr;
        static std::map<G4double*,G4double> tuneUnits;
public:
        /// Constructor
        BLTune() { }

        /// Destructor
        virtual ~BLTune() { }

        /// defineTunableArg() will define a tunable argument.
        static void defineTunableArg(G4double& arg, G4double units, G4String expr);

        /// copyTunableArg() will copy a tunable argument; for use in the copy
        /// constructor of Element classes.
        static void copyTunableArg(G4double *newArg, const G4double *oldArg);

        /// isSet() returns true if the varaible name is set.
        static bool isSet(G4String name);

        /// set() will set the value of a tune variable, and update all
        /// arguments that use it.
        static void set(G4String& name, G4double value);

        /// unset() will remove a tune variable.
        static void unset(G4String& name);

        /// update() will update all tunable args with their current values.
        static void update();
};

#endif // BLTUNE_HH