Example #1
0
 def combine_particles(self,particle1,particle2):
     #get phase space of new particle
     
     #delete collided particles in state and mass
     #add new particle in state and mass
     
     #nparticles -= 1 
     
     mass1 = self.masses[particle1]
     mass2 = self.masses[particle2]
     
     xd1 = self.state[particle1,1,0]
     yd1 = self.state[particle1,1,1]
     
     xd2 = self.state[particle2,1,0]
     yd2 = self.state[particle2,1,1]
     
     totalmass = mass1+mass2
     
     newxd = ((mass1*xd1) + (m2*xd2))/totalmass
     newyd = ((mass1*yd1) + (m2*yd2))/totalmass
     
     self.masses = np.delete(self.masses,[particle1,particle2],axis=0)
     
     new_phase_vector = [self.state[particle1,0,0],self.state[particle1,0,1],[newxd,newyd]]
     self.masses = np.append(self.masses,totalmass,axis=0)
     
     self.Nparticles -= 1
     
     return(new_phase_vector)
Example #2
0
 def UpdateStateVectorRK4(self,t):
     self.event_horizon = self.get_event_horizon(t)
     new_state = np.ndarray((self.Nparticles,2,2))
     
     for particle in xrange(self.Nparticles):
         kstate = np.copy(self.state)
         #do RK4 shit
         k1 = self.dt * self.SingleParticleDerivativeVector(kstate,particle, t+self.dt)
         kstate[particle] = np.copy(self.state[particle]) + k1/2
         k2 = self.dt * self.SingleParticleDerivativeVector(kstate,particle,t+(self.dt/2))
         kstate[particle] = np.copy(self.state[particle]) + k2/2
         k3 = self.dt * self.SingleParticleDerivativeVector(kstate,particle,t+(self.dt/2))
         kstate[particle] = np.copy(self.state[particle]) + k3
         k4 = self.dt * self.SingleParticleDerivativeVector(kstate,particle,t+self.dt)
         new_state[particle] = np.copy(self.state[particle]) + (1/3)*(k1/2 + k2 + k3 + k4/2)
         
     
     #Get rid of gobbled or ejected particles 
     if self.cleanup != []:
         for particle in self.cleanup:
             print("\n***particle {} shit the bed at step {}***".format(particle,int(t/self.dt)))
             self.remove_particle(particle)
             new_state = np.delete(new_state,particle,axis=0)
             print("***particle {} removed***".format(particle))
             self.cleanup.remove(particle)
             if self.cleanup == []:
                 print("***cleanup completed***")
     self.cleanup = []
     
     #Cleanup collided particles
     if self.collisions != {}:
         print("*****")
         for key in self.collisions:
             p1 = self.collisions[key][1][0]
             p2 = self.collisions[key][1][1]
             new_particle = self.combine_particles()
             print("***{} and {} collided at step{}***".format(p1,p2,int(t/self.dt)))
             new_state = np.delete(new_state,[self.collisions[key][0],self.collisions[1]],axis=0)
             new_state = np.append(new_state,new_particle,axis = 0)
         self.collisions = {}
     return(new_state)
Example #3
0
    def UpdateStateVectorRK4(self,t):
        self.event_horizon = self.get_event_horizon(t)
        new_state = np.ndarray((self.Nparticles,2,3))
        
        for particle in xrange(self.Nparticles):

            kstate = np.copy(self.state)

            k1 = self.dt * self.SingleParticleDerivativeVector(kstate,particle, t)
            kstate[particle] = np.copy(self.state[particle]) + k1/2
            k2 = self.dt * self.SingleParticleDerivativeVector(kstate,particle,t+(self.dt/2))
            kstate[particle] = np.copy(self.state[particle]) + k2/2
            k3 = self.dt * self.SingleParticleDerivativeVector(kstate,particle,t+(self.dt/2))
            kstate[particle] = np.copy(self.state[particle]) + k3
            k4 = self.dt * self.SingleParticleDerivativeVector(kstate,particle,t+self.dt)
            new_state[particle] = np.copy(self.state[particle]) + (1/3)*(k1/2 + k2 + k3 + k4/2)
            
        
        #Get rid of gobbled or ejected particles 
        if self.cleanup != []:
            new_state = np.delete(new_state,self.cleanup,axis=0)
            self.remove_particle(particle)
            for particle in self.cleanup:
                print("\n***particle {} shit the bed at step {}***".format(particle,int(t/self.dt)))
                print("***particle {} removed***".format(particle))
                self.cleanup.remove(particle)
                if self.cleanup == []:
                	print("***cleanup completed***")
        self.cleanup = []
        
        
        big_particle_list = []
        big_vector_list = []
        new_masses_list = []
        
        

        #Cleanup collided particles
        if self.collisions == "inelastic":
            if self.collision_dict != {}:       
                for key in self.collision_dict:
                	particles = self.collision_dict[key][1]
                	m = 0
                	x = self.collision_dict[key][0][0]
                	y = self.collision_dict[key][0][1]
                	mvx = 0
                	mvy = 0
                	for particle in particles:
                	    m += self.masses[particle]
                	for particle in particles:
                	    mvx += (self.state[particle][1][0]*self.masses[particle])
                	    mvy += (self.state[particle][1][1]*self.masses[particle])
                	    big_particle_list.append(particle)
                	new_masses_list.append(m)
                new_particle = [[x,y],[mvx/m,mvy/m]]
                big_vector_list.append(new_particle)

                self.masses = np.delete(self.masses,big_particle_list,axis=0)
                self.masses = np.append(self.masses,np.array(new_masses_list),axis = 0)
                new_state = np.delete(new_state,big_particle_list,axis=0)
                new_state = np.append(new_state,np.array(big_vector_list),axis = 0)
                self.Nparticles = len(new_state)
                self.collision_dict = {}
                self.collided_particles = np.array([])
        
        elif self.collisions == 'elastic':
            
            distances = squareform(pdist(self.state[:,0,:]))
            ind1, ind2 = np.where(distances < 2 * self.collision_radius)
            unique = (ind1 < ind2)
            ind1 = ind1[unique]
            ind2 = ind2[unique]
            new_collisions = zip(ind1,ind2)
            for i in new_collisions:
            	if i not in self.old_collisions:
            		i1 = i[0]
            		i2 = i[1]
            		
                	m1 = self.masses[i1]
                	m2 = self.masses[i2]
                	
                	x1 = new_state[i1,0,0]
                	y1 = new_state[i1,0,1]
                	z1 = new_state[i2,0,3]
                	x2 = new_state[i2,0,0]
                	y2 = new_state[i2,0,1]
                	z2 = new_state[i2,0,2]
                	
                	x1d = new_state[i1,1,0]
                	y1d = new_state[i1,1,1]
                	z1d = new_state[i1,1,2]
                	x2d = new_state[i2,1,0]
                	y2d = new_state[i2,1,1]
                	z2d = new_state[i2,1,2]
                	
                	new_state[i1, 1] = [(x1d*(m1-m2) + 2*m2*x2d)/(m1+m2),
                	                    (y1d*(m1-m2) + 2*m2*y2d)/(m1+m2),
                	                    (z1d*(m1-m2) + 2*m2*z2d)/(m1+m2)]
                	new_state[i2, 1] = [(x2d*(m2-m1) + 2*m1*x1d)/(m1+m2),
                	                    (y2d*(m2-m1) + 2*m1*y1d)/(m1+m2),
                	                    (z2d*(m2-m1) + 2*m1*z1d)/(m1+m2)]
            self.old_collisions = new_collisions
        return(new_state)