Error in ODE arguments in line 87

Hi everyone!

I'm trying to reed a .m funtion (with global variables) with the following script:

function [dY]=fun2(t,yfo)
for i=1:ng
    for j=1:ng
        if i~=j
         aux2_pe=C_fal(i,j)*sin(yfo(i)-yfo(j))+D_fal(i,j)*cos(yfo(i)-yfo(j));
        end
    end
     Pe_fal(i,1)=vg(i)^2*real(y_fal(i,i))+aux2_pe;
      dy(i+ng)=(Pm(i)-Pe_fal(i,1))/M(i);
      dy(i)=yfo(i+ng);
end
dY=[dy(1); dy(2); dy(3); dy(4); dy(5); dy(6)]
end

using the following codes for ODE23s:

yfo=[0.4677 0.4625 0.1171 0 0 0]; 
tspan=[0:0.002:0.198]; 
[tf,yf]=ode45('fun2',tspan,yfo);

and obtaining the following answer:

Undefined function or variable 'ng'.
Error in fun2 (line 5)for i=1:ng
Error in odearguments (line 87)
f0 = feval(ode,t0,y0,args{:});   % ODE15I sets args{1} to yp0.
Error in ode45 (line 115) odearguments(FcnHandlesUsed, solver_name, ode, tspan, y0, options, varargin);
Error in Untitled2 (line 246) [tf,yf]=ode45('fun2',tspan,yfo);

Answer 1

[Walter Roberson]

Global variables are only accessible in the workspaces where they are specifically declared with global.

Using global is not a good idea for this purpose. See http://www.mathworks.com/help/matlab/math/parameterizing-functions.html

[Mariana]

Thanks.