Given:
- a function y^*(x, {\bf p}) of the argument x and set of model parameters {\bf p} = \{ p_m\}_{m = 1..M} = \{p_1, p_2, ... p_M\}
- a discrete finite training dataset: \{ (x_k, y_k)\}_{k = 1..N} = \{ (x_0, y_0), (x_1, y_1), ..., (x_N, y_N) \} representing the available knowledge about the system the model is trying to describe
then matching procedure assumes searching for the specific set of model parameters {\bf p}_{\rm bestfit} to minimize the goal function:
G({\bf p}) = \sum_{k=1}^N \, \Psi \left( y^*(x_k) - y_k \right) \rightarrow \textrm{min} \ \Longleftrightarrow \ {\bf p} = {\bf p}_{\rm bestfit} |
where \Psi(z) is the discrepancy distance function.
The most popular choices are \Psi(z) = z^2 and \Psi(z) = |z|.
See also
Human / Science / Formal Science / System Science / System Model