Solving a system of nonlinear equations with unorganized unknowns?
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Ideally when using fsolve, my entire solution vector will be unknown. However my unknowns are broken down into 2 vectors x and r such that some values of my x vector are always fixed as they are boundary conditions but the summation of the length of x which are unknown, and r gives me the total number of unknowns. Is there a way I can use fsolve to pick the indices I would like it to solve leaving the boundary conditions the way they are?.
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Matt J
on 4 Oct 2019
Edited: Matt J
on 4 Oct 2019
If you use lsqnonlin instead of fsolve, you can set a vector of upper and lower bounds ub and lb on the solution. Just set ub(i)=lb(i) for those x(i) elements you want constrained to something known, e.g.,
p0=[x0(:);r0(:)]; %Initial guess
N=numel(p0);
[lb,ub]=deal(-inf(N,1), +inf(N,1));
ub(1:3)=10; lb(1:3)=10; %constrain x(1:3) to equal 10
p=lsqnonlin(@yourFunction,p0,lb,ub)
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