Minimize a function to a desired value

Hello everyone, i need your help :)

I have a function that returns a vector D and a vector of variables L. i want to minimise D starting from an initial vectror L0.

I am using "lsqnonlin". L=lsqnonlin(fun,L0,lb,ub).

it works perfectly, however i want D to be minimised to a certain value that i define. The bounds of the solver are set for L not D.

So my question is: how do i define the value of D to be minimised to?

i hope i was clear enough. i cant give the code since it is a very big one.

Thanks in advance :)

Answer 1

[Steven Lord]

"D to be minimised to a certain value" -- so you don't actually want to minimize your function but instead want to find a solution to the system of equations fun(x) = certain_value [or to write it another way, fun(x) - certain_value = 0? In that case, take a look at fsolve instead of lsqnonlin.

[Asma SEDDAOUI]

it doesn't work because i also need bounds on L. i thought maybe in the options of the solver. is it a good approach?

[Asma SEDDAOUI]

oh i found it. it was very easy. still use lsqnonlin but the returned value is D=fun(x)-d0. d0 is the "certain value".

thank you very much