Error in fsolve: "Not enough input arguments"

Hi all,

I hope you might be able to help me out. I get an error message saying "Not enough input arguments" in my code using fsolve below.

First I run some codes giving me the parameter called rho, c, count, alpha, s_UI, lambda, s_SA, q, and k.

Then I run the following:

fun = @(x) flow_eq;

x0 = zeros(2*c*count);

x = fsolve(fun,x0)

Where flow_eq is:

function [F] = flow_eq(x, rho, c, count, alpha, s_UI, lambda, s_SA, q, k)

F(1)=(1-rho)*x(c*count+1)-(1-alpha*s_UI)*lambda*x(2);%(1-rho)*e_SA(c*count-1)-(1-alpha*s_UI)*lambda*u_UI;

F(2)=sum(x(1:2*c*count))-1;

for i=1:c*count-1

F(i+2)=alpha*s_SA(q(i))*x(c*count+1+q(i))-x(2+i);

F(c*count+1+i)=rho*x(2+k(i))-alpha*s_SA(i)*x(c*count+1+i);

end

end

Any ideas? - Thanks!

Answer 1

[Star Strider]

Your ‘fun’ is not collecting the rest of the input arguments to ‘flow_eq’.

See if changing it to this helps:

fun = @(x) flow_eq(x, rho, c, count, alpha, s_UI, lambda, s_SA, q, k);

Be sure all the other variables are present in your workspace before you define ‘fun’.

[Christian E]

It doesn't. But the error message has now changed to:

In an assignment A(I) = B, the number of elements in B and I must be the same.

Error in flow_eq (line 8) F(1)=(1-rho)*x(c*count+1)-(1-alpha*s_UI)*lambda*x(2);%(1-rho)*e_SA(c*count-1)-(1-alpha*s_UI)*lambda*u_UI;

Error in @(x)flow_eq(x,rho,c,count,alpha,s_UI,lambda,s_SA,q,k)

Error in fsolve (line 241) fuser = feval(funfcn{3},x,varargin{:});

Error in flow_main (line 4) x = fsolve(fun,x0) Caused by: Failure in initial user-supplied objective function evaluation. FSOLVE cannot continue.

[Christian E]

Update: I seems all variables wasn't specified correctly. It might be running now. Thanks!

[Star Strider]

My pleasure!

(Away for a few minutes here.)

See if completely vectorising this line (I’ve done it here) will solve the problem:

F(1)=(1-rho).*x(c*count+1)-(1-alpha.*s_UI).*lambda.*x(2);       %(1-rho)*e_SA(c*count-1)-(1-alpha*s_UI)*lambda*u_UI;

See Array vs. Matrix Operations for details. Beyond that I have no idea, because I don’t know the dimensions of your variables. To be assigned to a scalar array element such as ‘F(1)’, the operation must produce a scalar value.