Function definition is misplaced or improperly nested error

function [v,y] = call_dstate()

for h_s = [1 3 2 ]

for h_d = [3 1 6]

for MA = [1.5 2.5 3.5]

for D_d = 0.0254*[1.25 1.75 2.25]

for D_s = 0.0254*[1.25 1.75 2.25]

for D_p = 0.0254*[2.5 3.5 4.5]

for L = [0.10 0.14 0.18]

y = [0.15 0.094];

v0 = 0.01;

m =64.5;

x = 0.7;

b = 0.625;

a = 0.250;

g = 9.8;

A_d = (D_d.^2)*3.14*0.25;

D_s = 0.0254;

A_s = (D_s^2)*3.14*.25;

l_d = 4.572;

l_s = 6.096;

A_p = ((D_p).^2)*3.14*0.25;

m_p = 0.2;

rho = 1000;

uk = 0.06;

uf = 0.4;

up = 0.00089;

h = 0.001;

t_w= 0.05;

A_w = t_w*D_p.*3.14;

z=0.2946*MA-0.1761;

M_tr= 2;

L_tr=0.5;

P=173.7;

R_pin=0.05;

M_T=2*m_p*(A_d/A_p)^2+(L+l_d+l_s)*rho*((A_d)^2/A_p)+(2*M_tr*L_tr^2/a^2)+z^2*MA^2*m*(A_d/A_p)^2;

c0=(1-2*x)*A_p*P/(A_d*M_T);

c1=(rho*g*(h_s*A_s+h_d*A_d+L*A_p)+z(1)*m*g*MA)/M_T;

c2=(2*rho*g*A_p)/M_T;

c3=(2*uf*b+25.12*up*L*h)*A_d/(h*M_T*A_p);

c4=(0.124*rho^0.75*up^0.25*[l_d*D_d^0.25+l_s*D_s^0.25]*(A_d/A_s)^1.75)/M_T;

c5=rho*[((A_d)^2/A_s)*[0.5+0.5+0.2+0.4+0.5]+0.5*((A_d)^2/A_p)+A_d*(0.5+0.4+0.2+1)+0.5*((A_d)^2/A_p)]/(2*M_T);

c6=uk*R_pin*[((2*M_tr*L_tr*A_d^2)/(a^2*A_p^2))+((m*MA*z^2*A_d^2)/(a*A_p^2))];

% dstate evaluates r.h.s. of the ode

[y,v] = ode45( @dstate ,y ,v0);

disp([y,v])

function dvdy = dstate(y,v)

v = ([c0]/v^2)-([c1]/v)-([c2]*y/v)-[c3]-[c4].*v^0.75-[c5]*v-([c6]*v/(sqrt(a^2-(y-0.047)^2)));% This is ODE

end

end

end

end

end

end

end

end

end

%%

I have used combination of different parameters using for loops. But differential equation is not getting solved. How should I tackle with this?

Answer 1

[Stephen23]

Once the code is aligned properly then the problem is clear:

for ...
    for ...
        for ...
            for ...
                for ...
                    for ...
                        for ...
                            ...
                            function dvdy = dstate(y,v)
                            v = ([c0]/v^2)-([c1]/v)-([c2]*y/v)-[c3]-[c4].*v^0.75-[c5]*v-([c6]*v/(sqrt(a^2-(y-0.047)^2)));% This is ODE
                            end
                        end
                    end
                end
            end
        end
    end
end

Functions cannot be defined inside of loops or of any other code constructs. They can be defined at file level only.

You will need to replace that invalid function definition with an anonymous function:

https://www.mathworks.com/help/matlab/matlab_prog/anonymous-functions.html

Note that your code contains many syntax warnings that I strongly suggest that you fix.

[SUSHANT CHAVAN]

Thank you for suggestion.