ode error

Hi all, i want to ask about my M-File. I cant run this code i made

function dGdW = PBR(W,Y)

global yao Fk0 Q0  T0 Dp miu G P0 A rhog0 rhoCat phi
%dGdW = zeros(3,1);

   X = Y(1); % conversion
   T = Y(2); % temperature
   y = Y(3); % P/Po

... (another script)

dGdW = [-rate/Fao
       rate*dHr/(Fa*Cpa+Fb*Cpb+Fc*Cpc+Fd*Cpd*Fe*Cpe)
     -(alpha/(2*y))*(1+ea*X)*(T/T0)];

i'm running that in one m-file using this :

[w,Y] = ode23s(@PBR,[0 37.5],[0 450 1])

when i run, i get this error code:

"Solving PBR requires an initial condition vector of length 3."

Why is that error occurs? I have no idea why that error occurs, because I think I have enter correct initial conditions.

Thanks for help

Answer 1

[Jan]

I do not see the error in the posted code. I suggest to use the debugger to find out more:

dbstop if error

Then inspect the current values of the variables and the caller stack.

[Taniadi]

thanks for the advice :) . I have found the errors. It is because I forgot to global variables i used in second functions. So it gave third output error.