Least squares
= Least squares
{title2=$\min_x\frac12\sum_jR_j(x)^2$}
{wiki}
The <least squares> approach chooses parameters by minimizing the sum of squared residuals. A <linear least-squares problem> has affine residuals, whereas <nonlinear least squares> permits nonlinear dependence on the parameters. The <Euclidean norm> makes the objective $\tfrac12\|R(x)\|_2^2$; the factor one-half simplifies its derivatives without changing its minimizers.