Not enough input arguments; fzero function

Dear All,

My follwoing code invoking fzero results in an error, 'Not enough input arguemnts'; I cannot quite figure out where the problem is. Any inputs are greately appreciated.

clc; clear all; close all;

global R mole_frac Cp T_Ref Avg_Cp_Bub_mix Avg_Cp_EG_mix T
R = 8.314; T_Ref = 298;
Cp_1 = [3.376; 0.557e-3; 0; -0.031e5; 0]; Cp_2 = [5.457; 1.045e-3; 0; -1.157e5; 0];
Cp_3 = [1.702; 9.081e-3; -2.164e-6; 0; 0]; Cp_4 = [3.249; 0.422e-3; 0; 0.083e5; 0];
Cp_5 = [3.47; 1.45e-3; 0; 0.121e5; 0]; Cp_6 = [3.28; 0.593e-3; 0; 0.04e5; 0];
Cp_7 = [3.931; 1.49e-3; 0; -0.232e5; 0]; Cp_8 = [3.639; 0.506e-3; 0; -0.227e5; 0];

Cp = [Cp_1 Cp_2 Cp_3 Cp_4 Cp_5 Cp_6 Cp_7 Cp_8];      

f_B = [1.0e-05;1.0e-05;1.0e-05;1.0e-05;128.4804;1.0e-05;1.0e-05;61.4471]
f_EG = [1.0e-05;1.0e-05;1.0e-05;1.0e-05;124.51957;1.0e-05;1.0e-05;59.5528]
T = [800;850];

f_Total = f_B + f_EG; 
mole_frac = (f_Total)/sum(f_Total);
B_mole_frac = f_B/sum(f_B); EG_mole_frac = f_EG/sum(f_EG);

% Estimate species specific average Cp values in the bubble phase (J/mol/K)
for i = 1:length(Cp)
Avg_Cp_Bub(i,1) = (R/(T(1)- T_Ref))*(Cp(1,i)*(T(1)- T_Ref)+(1/2)*Cp(2,i)*(T(1)^2- T_Ref^2)+(1/3)*Cp(3,i)*(T(1)^3- T_Ref^3)-Cp(4,i)*(1/T(1)-1/T_Ref)+(1/4)*Cp(5,i)*(T(1)^4- T_Ref^4));
end
Avg_Cp_Bub_mix = sum(B_mole_frac.*Avg_Cp_Bub)

% Estimate average Cp values (J/mol/K) of the species corresponding to prevailing emulsion gas temperature
for i = 1:length(Cp)
Avg_Cp_EG(i,1) = (R/(T(2)- T_Ref))*(Cp(1,i)*(T(2)- T_Ref)+(1/2)*Cp(2,i)*(T(2)^2- T_Ref^2)+(1/3)*Cp(3,i)*(T(2)^3- T_Ref^3)-Cp(4,i)*(1/T(2)-1/T_Ref)+(1/4)*Cp(5,i)*(T(2)^4- T_Ref^4));
end
Avg_Cp_EG_mix = sum(EG_mole_frac.*Avg_Cp_EG)

T_mix_0 = 810;

T_mix = fzero(fun,T_mix_0)
 
 
function F = fun(x)
                   
global R mole_frac Cp T_Ref Avg_Cp_Bub_mix Avg_Cp_EG_mix T f_B f_EG

Term1 = mole_frac(1,1)*(R./(x-T_Ref))*(Cp(1,1)*(x-T_Ref)+(1/2)*Cp(2,1)*(x^2-T_Ref^2)+(1/3)*Cp(3,1)*(x^3-T_Ref^3)-Cp(4,1)*(1/x-1/T_Ref)+(1/4)*Cp(5,1)*(x^4-T_Ref^4));
Term2 = mole_frac(2,1)*(R/(x-T_Ref))*(Cp(1,2)*(x-T_Ref)+(1/2)*Cp(2,2)*(x^2-T_Ref^2)+(1/3)*Cp(3,2)*(x^3-T_Ref^3)-Cp(4,2)*(1/x-1/T_Ref)+(1/4)*Cp(5,2)*(x^4-T_Ref^4));
Term3 = mole_frac(3,1)*(R/(x-T_Ref))*(Cp(1,3)*(x-T_Ref)+(1/2)*Cp(2,3)*(x^2-T_Ref^2)+(1/3)*Cp(3,3)*(x^3-T_Ref^3)-Cp(4,3)*(1/x-1/T_Ref)+(1/4)*Cp(5,3)*(x^4-T_Ref^4));
Term4 = mole_frac(4,1)*(R/(x-T_Ref))*(Cp(1,4)*(x-T_Ref)+(1/2)*Cp(2,4)*(x^2-T_Ref^2)+(1/3)*Cp(3,4)*(x^3-T_Ref^3)-Cp(4,4)*(1/x-1/T_Ref)+(1/4)*Cp(5,4)*(x^4-T_Ref^4));
Term5 = mole_frac(5,1)*(R/(x-T_Ref))*(Cp(1,5)*(x-T_Ref)+(1/2)*Cp(2,5)*(x^2-T_Ref^2)+(1/3)*Cp(3,5)*(x^3-T_Ref^3)-Cp(4,5)*(1/x-1/T_Ref)+(1/4)*Cp(5,5)*(x^4-T_Ref^4));
Term6 = mole_frac(6,1)*(R/(x-T_Ref))*(Cp(1,6)*(x-T_Ref)+(1/2)*Cp(2,6)*(x^2-T_Ref^2)+(1/3)*Cp(3,6)*(x^3-T_Ref^3)-Cp(4,6)*(1/x-1/T_Ref)+(1/4)*Cp(5,6)*(x^4-T_Ref^4));
Term7 = mole_frac(7,1)*(R/(x-T_Ref))*(Cp(1,7)*(x-T_Ref)+(1/2)*Cp(2,7)*(x^2-T_Ref^2)+(1/3)*Cp(3,7)*(x^3-T_Ref^3)-Cp(4,7)*(1/x-1/T_Ref)+(1/4)*Cp(5,7)*(x^4-T_Ref^4));
Term8 = mole_frac(8,1)*(R/(x-T_Ref))*(Cp(1,8)*(x-T_Ref)+(1/2)*Cp(2,8)*(x^2-T_Ref^2)+(1/3)*Cp(3,8)*(x^3-T_Ref^3)-Cp(4,8)*(1/x-1/T_Ref)+(1/4)*Cp(5,8)*(x^4-T_Ref^4));

Avg_Cp = (Term1 + Term2 + Term3 + Term4 + Term5 + Term6 + Term7 + Term8);
F = sum(f_B+f_EG)*(Avg_Cp)*(x - T_Ref) - (sum(f_B))*(Avg_Cp_Bub_mix)*(T(1)- T_Ref) - (sum(f_EG))*(Avg_Cp_EG_mix)*(T(2)- T_Ref);
end

Thanks in adavance!

Regards,

KD

[Dyuman Joshi]

You need to define your input function as an anonymous function.

You will also need to change the definition of other variables according.

Answer 1

[Alan Stevens]

Replace

T_mix = fzero(fun,T_mix_0);

by

T_mix = fzero(@fun,T_mix_0);

[Kareemulla Dudekula]

Thanks very much, Alan; this fixed the problem. I should have been more attetive to the prescribed syntax.