File indexing completed on 2024-09-08 03:35:52

 /*
     SPDX-FileCopyrightText: 2007 Vladimir Kuznetsov <ks.vladimir@gmail.com>
 
     SPDX-License-Identifier: GPL-2.0-or-later
 */
 
 /** \file particle.h
  *  \brief Particle and ChargedParticle classes
  */
 
 #ifndef STEPCORE_PARTICLE_H
 #define STEPCORE_PARTICLE_H
 
 #include "world.h"
 #include "vector.h"
 #include "object.h"
 
 namespace StepCore {
 
 class Particle;
 class ChargedParticle;
 
 /** \ingroup errors
  *  \brief Errors object for Particle
  */
 class ParticleErrors: public ObjectErrors
 {
     STEPCORE_OBJECT(ParticleErrors)
 
 public:
     /** Constructs ParticleErrors */
     explicit ParticleErrors(Item* owner = nullptr)
         : ObjectErrors(owner), _positionVariance(0,0), _velocityVariance(0,0),
           _forceVariance(0,0), _massVariance(0) {}
 
     /** Get owner as Particle */
     Particle* particle() const;
 
     /** Get position variance */
     const Vector2d& positionVariance() const { return _positionVariance; }
     /** Set position variance */
     void setPositionVariance(const Vector2d& positionVariance) {
         _positionVariance = positionVariance; }
 
     /** Get velocity variance */
     const Vector2d& velocityVariance() const { return _velocityVariance; }
     /** Set velocity variance */
     void setVelocityVariance(const Vector2d& velocityVariance) {
         _velocityVariance = velocityVariance; }
 
     /** Get acceleration variance */
     Vector2d accelerationVariance() const;
 
     /** Get force variance */
     const Vector2d& forceVariance() const { return _forceVariance; }
     /** Set force variance */
     void setForceVariance(const Vector2d& forceVariance) {
         _forceVariance = forceVariance; }
 
     /** Increment force variance */
     void applyForceVariance(const Vector2d& forceVariance) {
         _forceVariance += forceVariance; }
 
     /** Get mass variance */
     double massVariance() const { return _massVariance; }
     /** Set mass variance */
     void   setMassVariance(double massVariance) {
         _massVariance = massVariance; }
 
     /** Get momentum variance */
     Vector2d momentumVariance() const;
     /** Set momentum variance (will modify velocity variance) */
     void setMomentumVariance(const Vector2d& momentumVariance);
 
     /** Get kinetic energy variance */
     double kineticEnergyVariance() const;
     /** Set kinetic energy variance (will modify velocity variance) */
     void setKineticEnergyVariance(double kineticEnergyVariance);
 
 protected:
     Vector2d _positionVariance;
     Vector2d _velocityVariance;
     Vector2d _forceVariance;
     double _massVariance;
     friend class Particle;
 };
 
 /** \ingroup bodies
  *  \brief Particle with mass
  */
 class Particle: public Body
 {
     STEPCORE_OBJECT(Particle)
 
 public:
     enum {
         PositionOffset = 0 ///< Offset of particle position in variables array
     };
 
     /** Constructs a particle */
     explicit Particle(const Vector2d &position = Vector2d::Zero(),
             const Vector2d &velocity = Vector2d::Zero(), double mass = 1);
 
     /** Get position of the particle */
     const Vector2d& position() const { return _position; }
     /** Set position of the particle */
     void setPosition(const Vector2d& position) { _position = position; }
 
     /** Get velocity of the particle */
     const Vector2d& velocity() const { return _velocity; }
     /** Set velocity of the particle */
     void setVelocity(const Vector2d& velocity) { _velocity = velocity; }
 
     /** Get acceleration of the particle */
     Vector2d acceleration() const { return _force/_mass; }
 
     /** Get force that acts upon particle */
     const Vector2d& force() const { return _force; }
     /** Set force that acts upon particle */
     void setForce(const Vector2d& force) { _force = force; }
 
     /** Apply force to the body */
     void applyForce(const Vector2d& force) { _force += force; }
 
     /** Get mass of the particle */
     double mass() const { return _mass; }
     /** Set mass of the particle */
     void   setMass(double mass) { _mass = mass; }
 
     /** Get momentum of the particle */
     Vector2d momentum() const { return _velocity * _mass; }
     /** Set momentum of the particle (will modify only velocity) */
     void setMomentum(const Vector2d& momentum) { _velocity = momentum / _mass; }
 
     /** Get kinetic energy of the particle */
     double kineticEnergy() const { return _mass * _velocity.squaredNorm()/2; }
     /** Set kinetic energy of the particle (will modify only velocity) */
     void setKineticEnergy(double kineticEnergy);
 
     int  variablesCount() override { return 2; }
     void getVariables(double* position, double* velocity,
                           double* positionVariance, double* velocityVariance) override;
     void setVariables(const double* position, const double* velocity,
               const double* positionVariance, const double* velocityVariance) override;
     void addForce(const double* force, const double* forceVariance) override;
     void resetForce(bool resetVariance) override;
     void getAccelerations(double* acceleration, double* accelerationVariance) override;
     void getInverseMass(VectorXd* inverseMass,
                         DynSparseRowMatrix* variance, int offset) override;
 
     /** Get (and possibly create) ParticleErrors object */
     ParticleErrors* particleErrors() {
         return static_cast<ParticleErrors*>(objectErrors()); }
 
 protected:
     ObjectErrors* createObjectErrors() override { return new ParticleErrors(this); }
 
     Vector2d _position;
     Vector2d _velocity;
     Vector2d _force;
     double _mass;
 };
 
 /** \ingroup errors
  *  \brief Errors object for ChargedParticle
  */
 class ChargedParticleErrors: public ParticleErrors
 {
     STEPCORE_OBJECT(ChargedParticleErrors)
 
 public:
     /** Constructs ChargedParticleErrors */
     explicit ChargedParticleErrors(Item* owner = nullptr)
         : ParticleErrors(owner), _chargeVariance(0) {}
 
     /** Get owner as ChargedParticle */
     ChargedParticle* chargedParticle() const;
 
     /** Get charge variance */
     double chargeVariance() const { return _chargeVariance; }
     /** Set charge variance */
     void   setChargeVariance(double chargeVariance) {
         _chargeVariance = chargeVariance; }
 
 protected:
     double _chargeVariance;
     friend class ChargedParticle;
 };
 
 
 /** \ingroup bodies
  *  \brief ChargedParticle with mass and charge
  */
 class ChargedParticle: public Particle
 {
     STEPCORE_OBJECT(ChargedParticle)
 
 public:
     /** Constructs a charged particle */
     explicit ChargedParticle(const Vector2d &position = Vector2d::Zero(),
             const Vector2d &velocity = Vector2d::Zero(), double mass = 1, double charge = 0)
                 : Particle(position, velocity, mass), _charge(charge) {}
 
     /** Charge of the particle */
     double charge() const { return _charge; }
     /** Charge of the particle */
     void setCharge(double charge) { _charge = charge; }
 
     /** Get (and possibly create) ChargedParticleErrors object */
     ChargedParticleErrors* chargedParticleErrors() {
         return static_cast<ChargedParticleErrors*>(objectErrors()); }
 
 protected:
     ObjectErrors* createObjectErrors() override { return new ChargedParticleErrors(this); }
 
     double _charge;
 };
 
 } // namespace StepCore
 
 #endif