too many input arguments error

I keep getting this error but I do not see what is wrong. I need to plot concentrations of species a through g over a time tau

This is my code:

        c0 = [2 2 0 0 0 0 0]; %feed concentrations
        v = [-2 -1 1 1 0 0 0;
              0 0 -2 0 1 1 0;
              0 -1 0 0 0 -1 1]; %stoichiometric matrix
        k = [0.100 0.05 0.037 2.5 .6]; %rate constants
        options = []; %options use by fsolve

% loop over tau2's
for tau2vec=[0:0.5:30];

      [c2,fval,exitflag] = fsolve(@mysolv,c0,options);
      if exitflag<=0, warning('fsolve did not converge'),end

end
plot(tau2vec,ca2,'-r',tau2vec,cb2,'-b', tau2vec,cc2,'.-g',tau2vec,cd2,'-',tau2vec,ce2,'oy',tau2vec,cf2,'-',tau2vec,cg2,'+b');
xlabel('time (min)')
legend('c_A','c_B','c_C','c_D','c_E','c_F','c_G',0)
ylabel('concentration (M)')
title('Concentration Profiles Part B')

% function definition, fsolve will iterate on c2 until mysolv(c2) is zero
    function y = mysolv(c2)
        ca2 = c2(1);
        cb2 = c2(2);
        cc2 = c2(3);
        cd2 = c2(4);
        ce2 = c2(5);
        cf2 = c2(6);
        cg2 = c2(7);
        r2 = [k(1)*ca2^2*cb2 - k(2)*cc2*cd2;
            k(3)*cc2^2;
            k(4)*cb2*cf2-k(5)*cg2];
        R2 = v'*r2;
        y = c0 - c2 + R2*tau2vec; % tau2 and c0 are defined outside the function
    end

end

[Walter Roberson]

Which line is reporting too many input arguments?

Answer 1

[Brian B]

Where do you define ca2, cb2, ...? Do you need to get those from the value of c2 at each iteration of your loop?

[Anna Dorfi]

Yes. I need to output each species concentration from the c2 value that is being solved. The initial species concentrations are in the c0 vector.

[Brian B]

Currently you're overwriting the value of c2 at every iteration. You should do something like

TAU2VEC = [0:0.5:30];
C2 = zeros(length(c0), length(TAU2VEC)
for k=1:length(TAU2VEC)
      tau2vec =TAU2VEC(k);  
      [c2,fval,exitflag] = fsolve(@mysolv,c0,options);
      if exitflag<=0, warning('fsolve did not converge'),end
      C2(:,k) = c2;
end

Then you'll plot with C2 and TAU2VEC.