`scipy.optimize._dcsrch:DCSRCH._iterate`

source: build-install/usr/lib/python3.14/site-packages/scipy/optimize/_dcsrch.py:269

Signature

def _iterate(self, stp, f, g, task)

Parameters

stp : float: The current estimate of a satisfactory step. On initial entry, a positive initial estimate must be provided.
f : float: On first call f is the value of the function at 0. On subsequent entries f should be the value of the function at stp.
g : float: On initial entry g is the derivative of the function at 0. On subsequent entries g is the derivative of the function at stp.
task : bytes: On initial entry task must be set to 'START'.
On exit with convergence, a warning or an error, the: variable task contains additional information.

Returns

: stp, f, g, task: tuple

stp: the current estimate of a satisfactory step if task = 'FG'. If task = 'CONV' then stp satisfies the sufficient decrease and curvature condition.
f: the value of the function at stp.
g: the derivative of the function at stp.
task: On exit task indicates the required action:

If task(1:2) == b'FG' then evaluate the function and derivative at stp and call dcsrch again.
If task(1:4) == b'CONV' then the search is successful.
If task(1:4) == b'WARN' then the subroutine is not able to satisfy the convergence conditions. The exit value of stp contains the best point found during the search.

If task(1:5) == b'ERROR' then there is an error in the input arguments.

Aliases

scipy.optimize._dcsrch.DCSRCH._iterate