Not Enough Input Arguments

Hi, I am trying to solve this ODE problem, but I kept getting the "not enough input arguments" for the FT line. What is the mistake that I made?Here's my code:

function dFdV = etOH_prod(V,F)
dFdV = zeros(4,1);
% A = C2H4  
% B = H2O 
% C = C2H5OH  
% D = (C2H5)2O  
% F(1) = FA;
% F(2) = FB;
% F(3) = FC;
% F(4) = FD;
CTO = 0.9570;
kf1 = 4981.8737; % forward rate_1
kr1 = 1623976.823; % reverse rate_1
k2 = 3792.6052; % forward rate_2
FT = F(1) + F(2) + F(3) + F(4);
CA = CTO*( F(1)/FT );
CB = CTO*( F(2)/FT );
CC = CTO*( F(3)/FT );
r1A = -kf1*CA*CB + kr1*CC;
r2C = -k2*CC;
r1B = r1A;
r1C = -r1A;
r2B = (-1/2)*r2C;
r2D = (-1/2)*r2C;
rA = r1A;
rB = r1B + r2B;
rC = r1C + r2C;
rD = r2D;
dFdV(1,:) = rA;
dFdV(2,:) = rB;
dFdV(3,:) = rC;
dFdV(4,:) = rD;
end

Answer 1

[Walter Roberson]

You tried to run the function by pressing the green Run button. Pressing the Run button has the effect of running the code without any input parameters.

MATLAB never searches the environment looking for variables with the same name as named parameters for a function. If you do not pass in values in positions corresponding to named parameters, then MATLAB always treats the named parameters as missing.

Answer 2

[Sam Chak]

Hi @Sue Xin,

There is no error in my simulation below:

[V, F]  = ode45(@etOH_prod, [0 10], ones(4, 1));
plot(V, F), grid on, xlabel('V'), ylabel('F')

function dFdV = etOH_prod(V,F)
    dFdV = zeros(4,1);
    % A = C2H4  
    % B = H2O 
    % C = C2H5OH  
    % D = (C2H5)2O  
    % F(1) = FA;
    % F(2) = FB;
    % F(3) = FC;
    % F(4) = FD;
    CTO = 0.9570;
    kf1 = 4981.8737; % forward rate_1
    kr1 = 1623976.823; % reverse rate_1
    k2 = 3792.6052; % forward rate_2
    FT = F(1) + F(2) + F(3) + F(4);
    CA = CTO*( F(1)/FT );
    CB = CTO*( F(2)/FT );
    CC = CTO*( F(3)/FT );
    r1A = -kf1*CA*CB + kr1*CC;
    r2C = -k2*CC;
    r1B = r1A;
    r1C = -r1A;
    r2B = (-1/2)*r2C;
    r2D = (-1/2)*r2C;
    rA = r1A;
    rB = r1B + r2B;
    rC = r1C + r2C;
    rD = r2D;
    dFdV(1,:) = rA;
    dFdV(2,:) = rB;
    dFdV(3,:) = rC;
    dFdV(4,:) = rD;
end