MATLAB: Failure in initial objective function evaluation. FSOLVE cannot continue.

for loopfsolveMATLAB

I want to use fsolve in loop so that every time 'a' change, my X(1) value change and my other values change accordingly. Can anyone help with it And Also can you plot x1 and y1? Any help would be appreciated.
function F = Sample13(X,a)
x1=X(1);
x2=X(2);
y1=X(3);
y2=X(4);
p1sat=X(5);
p2sat=X(6);
p=X(7);
t=X(8);
f1 = p1sat-(exp(16.59158 -(3643.31/(t -33.424))));
f2 = p2sat-(exp(14.25326 -(2665.54/(t -53.424))));
f3 = p – 101.325;
f4 = x1 – a;
f5 = x1 + x2 – 1;
f6 = y1 + y2 – 1;
f7 = (y1*p)-(x1*p1sat);
f8 = (y2*p)-(x2*p2sat);
F=[f1;f2;f3;f4;f5;f6;f7;f8];
end
To Run Function M using this command:
fhandle=@Sample13;
for a=1:0.05:2
X0 = [0.5,0.5,0.5,0.5,200,200,101.325,333.9];
options = optimset('display','off');
X = fsolve(fhandle,X0,options);
disp(X)
end

Best Answer

Ahmed, use the following:
fhandle = @Sample13;
options = optimset('display','off','Algorithm','levenberg-marquardt');
a       = 1:0.05:2;
for ii = 1:numel(a)
    X0      = [0.5,0.5,0.5,0.5,200,200,101.325,333.9,a(ii)];   
    X       = fsolve(fhandle,X0,options);
    disp(X)
end
function F = Sample13(X)
x1=X(1);
x2=X(2);
y1=X(3);
y2=X(4);
p1sat=X(5);
p2sat=X(6);
p=X(7);
t=X(8);
a = X(9);
f1 = p1sat-(exp(16.59158 -(3643.31/(t -33.424))));
f2 = p2sat-(exp(14.25326 -(2665.54/(t -53.424))));
f3 = p - 101.325;
f4 = x1 - a;
f5 = x1 + x2 - 1;
f6 = y1 + y2 - 1;
f7 = (y1*p)-(x1*p1sat);
f8 = (y2*p)-(x2*p2sat);
F=[f1;f2;f3;f4;f5;f6;f7;f8];
end
Essentially, you treat a as another function input.
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