Not enough input arguments

Can you please help me in this error:

Not enough input arguments.

Error in eqs>eqs1 (line 46)
fcns(1) = F1- (r1*f1^2 + f1*(1-f1))/(r1*f1^2 + 2*f1*(1-f1) + r2*(1-f1)^2);

Error in fsolve (line 242)
            fuser = feval(funfcn{3},x,varargin{:});

Error in eqs (line 41)
result = fsolve(@eqs1,guess)

Caused by:
    Failure in initial objective function evaluation. FSOLVE cannot continue.

Program:

%global V F1in F2in Mw1 Mw2 Rho1 Rho2 Io f k11 r1 k22 r2 kt kd k12 k21 Vout TotalFin Pdot Residencetime
clc;
close all;

V = input('Please enter the vol of reactor (m3)');

F1in  = input('Please enter the molar flow rate of Monomer_1 (mol/s)');
F2in  = input(' Enter the molar flow rate of Monomer_2 (mol/s)');

 Mw1 = input('Enter the molar mass of Monomer_1 (g/gmol)');
Mw2 = input(' Enter the molar mass of Monomer_2 (g/gmol)');

Rho1 = input('Enter the density of Monomer_1 (g/cm3)');
Rho2 = input('Enter the density of Monomer_2 (g/cm3)');

Io = input(' Enter the initial concentration of initiator (mol/m3)');
 f = input(' Enter the initiator efficency');

k11 = input(' Enter the value of k11');
r1 = input('Enter the value of r1');

k22= input('Enter the value of k22');
r2 = input('Enter the value of r2');

kt= input('Enter the value of kt');

kd= input('Enter the value of kd');

k12 = k11/r1;
k21= k22/r2;

Vout = ( (F1in*Mw1)/Rho1 ) + ( (F2in*Mw2)/Rho2 );

TotalFin = F1in + F2in ;

Pdot = ( (f*kd*Io)/kt )^0.5;

Residencetime = V/Vout;

guess = [0.1 0.02];
result = fsolve(@eqs1,guess)

function fcns = eqs1(z,r1,r2,TotalFin,Residencetime,Pdot,k11,k22,k12,k21)
F1 = z(1);
f1 = z(2);  
fcns(1) = F1- (r1*f1^2 + f1*(1-f1))/(r1*f1^2 + 2*f1*(1-f1) + r2*(1-f1)^2);
fcns(2) = TotalFin/(TotalFin - 31.71/(104-51*F1)) - ((Residencetime*Pdot)*(k11*k22*f1^2 + 2*k21*k12*f1 - 2*k21*k12*f1^2 + k22*k12 + k22*k12*f1^2 - 2*k22*k12*f1))/(k12*(1-f1) + k21*f1) -1 ;
end

Answer 1

[Star Strider]

You need to pass all the arguments to ‘eqs1’ in your fsolve call.

Try this instead:

result = fsolve(@(z)eqs1(z,r1,r2,TotalFin,Residencetime,Pdot,k11,k22,k12,k21),guess)

[Aman tiwari]

Thanks strider.

But now its saying too many arguments.

rror using eqs>eqs1

Too many input arguments.

Error in eqs>@(z)eqs1(z,r1,r2,TotalFin,Residencetime,Pdot,k11,k22,k12,k21)

Error in fsolve (line 242)

fuser = feval(funfcn{3},x,varargin{:});

Error in eqs (line 42)

result = fsolve(@(z)eqs1(z,r1,r2,TotalFin,Residencetime,Pdot,k11,k22,k12,k21),guess)

Caused by:

Failure in initial objective function evaluation. FSOLVE cannot continue.

.

[Star Strider]

I cannot determine what the problem is.

When I tested your code with random constants (before I posted my Answer), it ran without error:

V = 100;                                                                % Create Constant
q = num2cell(rand(14,1));                                               % Create Random Constants
[F1in,F2in, Mw1,Mw2,Rho1,Rho2,Io,f,k11,r1,k22,r2,kt,kd] = q{:};         % Assign Random Constants

k12 = k11/r1;
k21= k22/r2;
Vout = ( (F1in*Mw1)/Rho1 ) + ( (F2in*Mw2)/Rho2 );
TotalFin = F1in + F2in ;
Pdot = ( (f*kd*Io)/kt )^0.5;
Residencetime = V/Vout;
guess = [0.1 0.02];
result = fsolve(@(z)eqs1(z,r1,r2,TotalFin,Residencetime,Pdot,k11,k22,k12,k21),guess)
function fcns = eqs1(z,r1,r2,TotalFin,Residencetime,Pdot,k11,k22,k12,k21)
F1 = z(1);
f1 = z(2);  
fcns(1) = F1- (r1*f1^2 + f1*(1-f1))/(r1*f1^2 + 2*f1*(1-f1) + r2*(1-f1)^2);
fcns(2) = TotalFin/(TotalFin - 31.71/(104-51*F1)) - ((Residencetime*Pdot)*(k11*k22*f1^2 + 2*k21*k12*f1 - 2*k21*k12*f1^2 + k22*k12 + k22*k12*f1^2 - 2*k22*k12*f1))/(k12*(1-f1) + k21*f1) -1 ;
end

Check to be sure that your definition of ‘eqs1’ and your call to it are the same as in my code. (The result you get with the correct constants will be different from what I get with my code.)

[Aman tiwari]

Yes it worked.

Amazing.

.1769,0.1047,0.4843,53,104,.811,.903,20,.59,.176,.41---- values of input

But there is one issue my answer is F1 =0.2801 f1=0.0244

but i am getting

Solver stopped prematurely.

fsolve stopped because it exceeded the function evaluation limit,

options.MaxFunctionEvaluations = 200 (the default value).

result =

-28.2120 -0.0201

[Star Strider]

I cannot use your ‘values of input’ because those are only 11 and 15 are required. Your ‘eqns1’ function only takes 9 parameters, so those lengths are also incompatible.

This should help with the 'MaxFunctionEvaluations' problem:

options = optimoptions('fsolve', 'MaxFunctionEvaluations',1000, 'MaxIterations',1000);
guess = [0.1 0.02];
result = fsolve(@(z)eqs1(z,r1,r2,TotalFin,Residencetime,Pdot,k11,k22,k12,k21),guess,options)

See the documentation on optimoptions (link) for details.

Answer 2

[Stephen23]

You need to parameterize the objective function supplied to fsolve:

https://www.mathworks.com/help/matlab/math/parameterizing-functions.html

For example:

fun = @(z) eqs1(z,r1,r2,TotalFin,Residencetime,Pdot,k11,k22,k12,k21);
result = fsolve(fun,guess)

or use a nested function.

[Aman tiwari]

Thank you Stephen

But now saying too many arguments.

rror using eqs>eqs1

Too many input arguments.

Error in eqs>@(z)eqs1(z,r1,r2,TotalFin,Residencetime,Pdot,k11,k22,k12,k21)

Error in fsolve (line 242)

fuser = feval(funfcn{3},x,varargin{:});

Error in eqs (line 44)

result = fsolve(fun,guess)

Caused by:

Failure in initial objective function evaluation. FSOLVE cannot continue.