Allow the user to set some characteristics
Levenberg-Marquardt nonlinear least squares algorithm implemented
in nls.lm.
nls.lm.control(ftol = sqrt(.Machine$double.eps),
ptol = sqrt(.Machine$double.eps), gtol = 0, diag = list(), epsfcn = 0,
factor = 100, maxfev = integer(), maxiter = 50, nprint = 0)A list with exactly nine components:
with meanings as explained under ‘Arguments’.
non-negative numeric. Termination occurs when
both the actual and predicted relative reductions in the sum of
squares are at most ftol. Therefore, ftol measures
the relative error desired in the sum of squares.
non-negative numeric. Termination occurs when
the relative error between two consecutive iterates is at most
ptol. Therefore, ptol measures the relative error
desired in the approximate solution.
non-negative numeric. Termination occurs when
the cosine of the angle between result of fn evaluation
\(fvec\) and any column of the Jacobian is at most gtol
in absolute value. Therefore, gtol measures the
orthogonality desired between the function vector and the
columns of the Jacobian.
a list or numeric vector containing positive
entries that serve as multiplicative scale factors for the
parameters. Length of diag should be equal to that of
par. If not, user-provided diag is ignored and
diag is internally set.
(used if jac is not provided) is a
numeric used in determining a suitable step for the
forward-difference approximation. This approximation assumes
that the relative errors in the functions are of the order of
epsfcn. If epsfcn is less than the machine
precision, it is assumed that the relative errors in the
functions are of the order of the machine precision.
positive numeric, used in determining the
initial step bound. This bound is set to the product of
factor and the \(|\code{diag}*\code{par}|\) if nonzero,
or else to factor itself. In most cases factor
should lie in the interval (0.1,100). 100 is a generally
recommended value.
integer; termination occurs
when the number of calls to fn has reached maxfev.
Note that nls.lm sets the value of maxfev to
100*(length(par) + 1) if
maxfev = integer(), where par is the list or
vector of parameters to be optimized.
positive integer. Termination occurs
when the number of iterations reaches maxiter.
is an integer; set nprint to be positive
to enable printing of iterates
J.J. Moré, "The Levenberg-Marquardt algorithm: implementation and theory," in Lecture Notes in Mathematics 630: Numerical Analysis, G.A. Watson (Ed.), Springer-Verlag: Berlin, 1978, pp. 105-116.
nls.lm