BVP4C: The derivative function ODEFUN should return a column vector of length 10

Hello

I have to resolve an ODE with boundary conditions, so I had to use the function bvp4c.

xa=-c;

    xb=c;
    solinit=bvpinit(linspace(xa,xb,20),[1 1 1 1 1 1 1 1 1 1]);
    sol=bvp4c(@(x,g)bvp4ode_g(x,g,GAMMA,B,z,y1,y2,y3,y4,y5,y6,y7,y8,y9),@(ga,gb)bvp4bc_g(ga,gb,a,a1,a2,K,nu1,nu2),solinit);
    xint=linspace(xa,xb,100);
    Sxint=deval(sol,xint);

    function bc=bvp4bc_g(ga,gb,a,a1,a2,K,nu1,nu2)
    bc=[ga(9)-1 ga(3) ga(4)-(3*a/a1)*ga(10) ga(8)+ga(7)*sqrt(2)*(K(2,1))^(1/4)+ga(6)*(K(2,1))^(1/2)-(3*a/a2)*ga(10) ga(7)+ga(6)*sqrt(2)*(K(2,1))^(1/4)+ga(5)*(K(2,1))^(1/2)+(2*sqrt(3)*nu2*(1-(nu2)^2)^(-1/2))*a/a2 gb(9)+1 gb(7) gb(8)-(3*a/a2)*gb(10) gb(4)+gb(3)*sqrt(2)*(K(1,1))^(1/4)+gb(2)*(K(1,1))^(1/2)-(3*a/a1)*gb(10) gb(3)+gb(2)*sqrt(2)*(K(1,1))^(1/4)+gb(1)*(K(1,1))^(1/2)+(2*sqrt(3)*nu1*(1-(nu1)^2)^(-1/2))*a/a1];
    end

function dydx=bvp4ode_g(x,g,GAMMA,B,z,y1,y2,y3,y4,y5,y6,y7,y8,y9)
dydx=[g(2) g(3) g(4) (y1+y3*y9)*g(1)+(y3*B(1,1))*g(3)+GAMMA(1,2)*y3*y8*g(5)+(y3*B(2,1))*g(7)+(y2+y3*y7)*g(9)+y3*z-y2 g(6) g(7) g(8) (GAMMA(2,1)+y6*y9)*g(1)+(y6*B(1,1))*g(3)+(y4+y6*y8)*g(5)+(y6*B(2,1))*g(7)+(y5+y6*y7)*g(9)+y6*z+y5 g(10) y9*g(1)+B(1,1)*g(2)+y8*g(5)+B(2,1)*g(7)+y3*g(9)+z];
endfunction dydx=bvp4ode_g(x,g,GAMMA,B,z,y1,y2,y3,y4,y5,y6,y7,y8,y9)
dydx=[g(2) g(3) g(4) (y1+y3*y9)*g(1)+(y3*B(1,1))*g(3)+GAMMA(1,2)*y3*y8*g(5)+(y3*B(2,1))*g(7)+(y2+y3*y7)*g(9)+y3*z-y2 g(6) g(7) g(8) (GAMMA(2,1)+y6*y9)*g(1)+(y6*B(1,1))*g(3)+(y4+y6*y8)*g(5)+(y6*B(2,1))*g(7)+(y5+y6*y7)*g(9)+y6*z+y5 g(10) y9*g(1)+B(1,1)*g(2)+y8*g(5)+B(2,1)*g(7)+y3*g(9)+z];
end

But I get this errors:

Error using bvparguments (line 109)
Error in calling BVP4C(ODEFUN,BCFUN,SOLINIT):
  The derivative function ODEFUN should return a column vector of length 10.

Error in bvp4c (line 130)
[n,npar,nregions,atol,rtol,Nmax,xyVectorized,printstats] = ...

Error in LR (line 69)
sol=bvp4c(@(x,g)bvp4ode_g(x,g,GAMMA,B,z,y1,y2,y3,y4,y5,y6,y7,y8,y9),@(ga,gb)bvp4bc_g(ga,gb,a,a1,a2,K,nu1,nu2),solinit); 
>>

Thanks for your help.

[Torsten]

Your vector of initial conditions has length 10, but you supply derivatives only for 9 equations ...

And the vectors you supply should be column vectors, not row vectors ...

Best wishes

Torsten.

Answer 1

[Walter Roberson]

You appear to be returning row vectors instead of column vectors.

[Nouhayla EL GHANI]

So what do you advise me to do?

[Steven Lord]

Return column vectors. The easiest way to do so is to have the functions whose handles you pass into the BVP solver transpose the outputs immediately before they return.

[Walter Roberson]

For example,

function bc=bvp4bc_g(ga,gb,a,a1,a2,K,nu1,nu2)
  bc=[ga(9)-1 ga(3) ga(4)-(3*a/a1)*ga(10) ga(8)+ga(7)*sqrt(2)*(K(2,1))^(1/4)+ga(6)*(K(2,1))^(1/2)-(3*a/a2)*ga(10) ga(7)+ga(6)*sqrt(2)*(K(2,1))^(1/4)+ga(5)*(K(2,1))^(1/2)+(2*sqrt(3)*nu2*(1-(nu2)^2)^(-1/2))*a/a2 gb(9)+1 gb(7) gb(8)-(3*a/a2)*gb(10) gb(4)+gb(3)*sqrt(2)*(K(1,1))^(1/4)+gb(2)*(K(1,1))^(1/2)-(3*a/a1)*gb(10) gb(3)+gb(2)*sqrt(2)*(K(1,1))^(1/4)+gb(1)*(K(1,1))^(1/2)+(2*sqrt(3)*nu1*(1-(nu1)^2)^(-1/2))*a/a1];
  bc = bc(:);    %make it into column vector
  end

[Nouhayla EL GHANI]

Thank you :)