Help with a code writing

I want to create a code that simulates multiple particles coliding with the walls of a box but I dont want the particles to colide with each other.

I alredy made a script for one particle, but Im having trouble making one for multiple ones.

Can someone help me please?

[Jayant]

you can post a snapof ur code or your script, it will be helpfull to tell u the changes. Where to add what...

[PS]

OK sorry I forgot about it thank you.

Here's the main script:

a=20;

b=10;

R=0.5;

dt=0.1;

np=3; %Number of particles

rx=a*rand(1,np);

ry=b*rand(1,np);

r=[rx;ry];

v=5*(2*rand(2,np)-1);

tmax=100;

t=0;

while (t<tmax)

for i=1:1:np

deltat(1,i)=(R-r(1,i))/v(1,i); deltat(2,i)=(a-R-r(1,i))/v(1,i);

deltat(3,i)=(R-r(2,i))/v(2,i); deltat(4,i)=(b-R-r(2,i))/v(2,i);

if deltat(1,i)<=4*eps

deltat(1,i)=1e6;

end

if deltat(2,i)<=4*eps

deltat(2,i)=1e6;

end

if deltat(3,i)<=4*eps

deltat(3,i)=1e6;

end

if deltat(4,i)<=4*eps

deltat(4,i)=1e6;

end

deltat_wall=[deltat(1,i),deltat(2,i),deltat(3,i),deltat(4,i)];

[deltat, column]=min(deltat_wall,[],2);

[deltat,particle]=min(deltat);

wall=column(particle);

animacion(r,v,a,b,R,dt,deltat) % the function is just to plot the box and the posicion of the particles

r=r+v*deltat;

ep=[[1;0],[-1;0],[0;1],[0;-1]];

v=v-2*dot(v,ep(:,wall))*ep(:,wall);

t=t+deltat;

end

end

Here´s the function:

function []= animacion(r,v,a,b,R,dt,deltat)

x1=0;

x2=a;

y1=0;

y2=b;

side_a=[x1,x2,x2,x1,x1];

side_b=[y1,y1,y2,y2,y1];

for t=0:dt:deltat

plot(side_a,side_b,'b-','Linewidth',2)

hold on

plot(r(1,:),r(2,:),'ko','MarkerFaceColor','k', 'MarkerSize',28*R)

xlim([-10,30])

ylim([-10,20])

drawnow

hold off

r=r+v*dt;

end

end

Hope its better now

[darova]

See this question

[PS]

Thank you for your answer but I still cannot understand how to do it for more particles using my script

[darova]

I can't run your script. I have some errors. Do you have errors?

[PS]

yes I have.If you take the cicle for and the i's on deltat you should see the animation with one particle.