Bug fix release.
line_search = "backtracking"
with a specified step_down
parameter, an incorrectly large number of gradient calculations was being
reported.step_down
argument with line_search = "backtracking"
, interpolation using function
and gradient evaluations is carried out. To get a typical Armijo-style
backtracking line search, specify a value for step_down
(e.g.
step_down = 0.5
to halve the step size), and only function evaluations are
used.A patch release to fix an incompatibility with R-devel.
class
was being checked directly and a scalar value was
assumed. The correct behavior is to use methods::is
.A patch release for a bug fix.
ls_max_fn
parameter), a
'bracket_step' not found
error could result. Thank you to reporter Charles
Driver.A patch release to fix an incompatibility with R-devel.
method = "TN"
). Can be controlled using the
tn_init
and tn_exit
options.method = "SR1"
), falling back to the BFGS direction if a
descent direction is not found.preconditioner
, which applies to the conjugate gradient and
truncated newton methods. The only value currently available is preconditioner = "L-BFGS"
which uses L-BFGS to estimate the inverse Hessian for
preconditioning. The number of updates to store for this preconditioner is
controlled by the memory
parameter, just as if you were using method = "L-BFGS"
.fg
list, supply a function hi
, that takes
the par
vector as input. The function can return a matrix (obviously not a
great idea for memory use), or a vector, the latter of which is assumed to be
the diagonal of the matrix.ls_max_alpha
(for line_search = "More-Thuente"
only): sets maximum value
of alpha that can be attained during line search.ls_max_alpha_mult
(for Wolfe-type line search only): sets maximum value that
can be attained by the ratio of the initial guess for alpha for the current line
search, to the final value of alpha of the previous line search. Used to stop
line searches diverging due to very large initial guesses.ls_safe_cubic
(for line_search = "More-Thuente"
only): if TRUE
,
use the safe-guarded cubic modification suggested by Xie and Schlick.cg_update = "prfr"
, the "PR-FR" (Polak-Ribiere/Fletcher-Reeves) conjugate
gradient update suggested by Gilbert and Nocedal.cg_udpate = "hs"
), Conjugate Descent (cg_udpate = "cd"
),
Dai-Yuan (cg_udpate = "dy"
) and Liu-Storey (cg_udpate = "ls"
).Initial release.