K1. Least squares approximation

Functions
void	_lmdif1 (void(*fcn)(int, int, double *, double *, int *), int m, int n, double x[], double fvec[], double tol, double work[], int lwork, int iwork[], int *info)
	Nonlinear least squares approximation (Levenberg-Marquardt method) (Jacobian not required) (simple driver)
void	_lmdif1_r (int m, int n, double x[], double fvec[], double tol, double work[], int lwork, int iwork[], int *info, double xx[], double yy[], int *irev)
	Nonlinear least squares approximation (Levenberg-Marquardt method) (Jacobian not required) (simple driver) (reverse communication version)

Detailed Description

This is the group of K1. Least squares approximation.