Passing arguments into fsolve without using globals

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Jesse
Jesse 2011-10-21
评论： MADAN MOHAN 2018-6-17
Hello,
How do I pass arguments, vectors, or constants into fsolve? A simple example:
REF=[x,y,z] <-- I want this to pass into 'myfun' during fsolve
[out,fval]=fsolve('myfun',y0)
...
function [Z]=myfun(y)
Z=[ REF(1)*y(1) + REF(2);
REF(3)*y(2) - REF(2)];
I am trying to avoid using globals.

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采纳的回答

Matt Tearle
Matt Tearle 2011-10-21
1) Rewrite myfun to take two inputs:
function Z = myfun(y,REF)
...
2) Use an anonymous function handle to make a function of one variable, with the second input to myfun (REF) embedded into it:
REF = [x,y,z];
f = @(y) myfun(y,REF); % function of dummy variable y
[out,fval]=fsolve(f,y0)
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Jesse
Jesse 2011-10-28
Good idea. I am familiar with structures in C-code. I think I should have no prob putting it into MATLAB format.
MADAN MOHAN
MADAN MOHAN 2018-6-17
Hello! I have been trying with reference to your example but i am getting certain errors: So in one script file "eqns.m", I have written the following lines of codes:
function F = eqns(x,k)
x1=x(1);
x2=x(2);
F(1) = x1.^2 + 2*x2.^2 - 5*x1 + 7*x2 - k;
F(2) = 3*x1.^2 - x2.^2 + 4*x1 +2*x2 - k;
end
And the other script file for the calling of the function into the fsolve is:
function f = solveit(x1, x2, k)
x0 = [x1; x2];
[z,fval] = fsolve(@(x)eqns(x,k),x0);
f = z;
end
And I call this function "solveit" in the commend window and I get the following error:
>> solveit(1,2,30)
Error using eqns
Too many input arguments.
Error in solveit>@(x)eqns(x,k) (line 7) [z,fval] = fsolve(@(x)eqns(x,k),x0);
Error in fsolve (line 217) fuser = feval(funfcn{3},x,varargin{:});
Error in solveit (line 7) [z,fval] = fsolve(@(x)eqns(x,k),x0);
Caused by: Failure in initial user-supplied objective function evaluation. FSOLVE cannot continue.

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