/*************************************************************************
*  Copyright (C) 2006 by Bruno Chareyre                                  *
*  bruno.chareyre@grenoble-inp.fr                                            *
*                                                                        *
*  This program is free software; it is licensed under the terms of the  *
*  GNU General Public License v2 or later. See file LICENSE for details. *
*************************************************************************/

#pragma once

#include<core/TimeStepper.hpp>

namespace yade { // Cannot have #include directive inside.

/*! \brief Compute the critical timestep of the leap-frog scheme based on global stiffness of bodies
	See usage details in TriaxialTest documentation (TriaxialTest is also a good example of how to use this class)
 */

class Interaction;
class BodyContainer;
class Scene;

class GlobalStiffnessTimeStepper : public TimeStepper
{
	private :
		vector<Vector3r> stiffnesses;
		vector<Vector3r> Rstiffnesses;
		vector<Vector3r> viscosities;
		vector<Vector3r> Rviscosities;
		void computeStiffnesses(Scene*);

		Real		newDt;
		bool		computedSomething,
 				computedOnce;
		void findTimeStepFromBody(const shared_ptr<Body>& body, Scene * ncb);
	
	public :
		virtual ~GlobalStiffnessTimeStepper();
	
		virtual void computeTimeStep(Scene*);
		virtual bool isActivated();
	// clang-format off
		YADE_CLASS_BASE_DOC_ATTRS_CTOR(
			GlobalStiffnessTimeStepper,TimeStepper,"An engine assigning the time-step as a fraction of the minimum eigen-period in the problem. The derivation is detailed in the chapter on :ref:`DEM formulation <DEMSimulations>`. The viscEl option enables to evaluate the timestep in a similar way for the visco-elastic contact law :yref:`Law2_ScGeom_ViscElPhys_Basic`, more detail in :yref:`GlobalStiffnessTimestepper::viscEl`. ",
			((Real,defaultDt,-1,,"used as the initial value of the timestep (especially useful in the first steps when no contact exist). If negative, it will be defined by :yref:`utils.PWaveTimeStep` * :yref:`GlobalStiffnessTimeStepper::timestepSafetyCoefficient`"))
			((Real,maxDt,Mathr::MAX_REAL,,"if positive, used as max value of the timestep whatever the computed value"))
			((Real,previousDt,Mathr::MAX_REAL,,"last computed dt |yupdate|"))
			((Real,timestepSafetyCoefficient,0.8,,"safety factor between the minimum eigen-period and the final assigned dt (less than 1)"))
			((bool,densityScaling,false,,"|yupdate| don't modify this value if you don't plan to modify the scaling factor manually for some bodies. In most cases, it is enough to set :yref:`NewtonIntegrator::densityScaling` and let this one be adjusted automatically."))
			((Real,targetDt,1,,"if :yref:`NewtonIntegrator::densityScaling` is active, this value will be used as the simulation  timestep and the scaling will use this value of dt as the target value. The value of targetDt is arbitrary and should have no effect in the result in general. However if some bodies have imposed velocities, for instance, they will move more or less per each step depending on this value."))
			((bool,viscEl,false,,"To use with :yref:`ViscElPhys`. if True, evaluate separetly the minimum eigen-period in the problem considering only the elastic contribution on one hand (spring only), and only the viscous contribution on the other hand (dashpot only). Take then the minimum of the two and use the safety coefficient :yref:`GlobalStiffnessTimestepper::timestepSafetyCoefficient` to take into account the possible coupling between the two contribution.")),
			computedOnce=false;)
	// clang-format on
		DECLARE_LOGGER;
};

REGISTER_SERIALIZABLE(GlobalStiffnessTimeStepper);

} // namespace yade

