ODE 15 solver, "Too many output arguments."

The basics, I am trying to Solve to ODE's using ODE15s, I have one M-file that asks for user inputs and assigns them to variables. But, when i run it I get an error "Too many output arguments. ====> alpha". How do I fix this? As you can probably tell from the code I am whats 10 levels below beginner. Oh and Im solving for pressure drop in a packed bed reactor.

Thanks,

1st Mfile

function dp = packbed(~,p)

dp = zeros(2,1);

dp(1) = (-1)*(alpha*((p0)^2))/(p(1))*((1+(ep))* p(2));

dp(2) = ((k)*(ca0)/(v0))*((1-p(2))/(1+(ep)*p(2)))*(((p(1))/(p0))^2); end

2nd Mfile

alpha1 = input('please enter a value for Alpha (Kg^-1):');

alpha = sprintf('%0.6f', alpha1);|

p01 = input('please enter a value for the initial pressure (atm):');

p0 = sprintf('%0.6f', p01);

% Epsilon is represented as "ep".

ep1 = input('please enter a value for Epsilon:');

ep = sprintf('%0.6f', ep1);

% k is represented as the rate constant.

k1 = input('please enter a value for the rake constant(m^3/kmol*kg*cat*h):');

k = sprintf('%0.6f', k1);

% v0 is the initial volume.

v01 = input('please enter a value for the initial volume (m^3):');

v = sprintf('%0.6f', v01);

% ca0 is the initial concentration of A at the inlet.

ca01 = input('please enter a value for the initial consentration of A (kmols/m^3):');

ca0 = sprintf('%0.6f', ca01);

pnot = [p0 0];

vnot = [v0 0];

wspan = [0 60];

run packbed

u = input('If you would like a plot of "Pressure vs Weight of the catalyst" type 1, or "Volume vs Weight of the catalyst" type 2:');

if u==1

    [p,w] = ode15s(@packbed, wspan, pnot);

    plot(p,w(:,1));

elseif u==2

    [v,w] = ode15s(@packbed, wspan, vnot);

    plot(v,w(:,1));

else

    disp('If you would like a plot of "Pressure vs Weight of the catalyst" type 1, or "Volume vs Weight of the catalyst" type 2:');

end

Answer 1

[Grzegorz Knor]

alpha is a matlab function. It set transparency properties for objects in current axes.

See also: How do I pass out extra parameters using ODE23 or ODE45 from the MATLAB ODE suite?

[Sam Hill]

Thank you!