matlab - Numerical solution of coupled dif eq -

matlab - Numerical solution of coupled dif eq -

so have set of 3 differentialequations want solve. can seen in code. problem, want combine these codes can have loop respect r (as shown.

what have:

t2 = 1; [t,y] = ode45(@ball, [0 5*t2] ,[0 0 -10]); figure plot(t,y(:,1),'-r',t,y(:,2),'-g',t,y(:,3),'-b') legend('x(t)','y(t)','z(t)') xlabel('time (in units of t2)') title(['plot rt2 = ',num2str(r)])

where @ball

`function dr = ball(t,b) t2 = 1; t1 = t2/2; d = 0; r = 0.2; dr = zeros(3,1); dr(1) = (-1/t2)*b(1)-d*b(2); dr(2) = (-1/t2)*b(2) + d*b(1) + r*b(3); dr(3) = (-1/t1)*b(3) - r*b(2) ; end`

what want single programme this, allow me include loop can vary r , create couple subplots. possible?

you can utilize anonymous function this.

change ball.m remove hard-coded r , replace input argument:

function dr = ball(t,b,r) t2 = 1; t1 = t2/2; d = 0; %// etc.

and replace ode45 phone call this:

r=0.4; [t,y] = ode45(@(t,b) ball(t,b,r), [0 5*t2] ,[0 0 -10]);

where @(t,b) ball(t,b,r) function inputs t , b calls ball.m value of r specified on previous line. can build for loop follows:

for r=0.2:.02:1 %// or whatever range want [t,y] = ode45(@(t,b) ball(t,b,r), [0 5*t2] ,[0 0 -10]); %// etc. end

matlab differential-equations