steppyngstounes 0.1.1

steppyngstounes / ˈstɛp ɪŋˌstoʊnz /

1. pl. n. [Middle English] Stones used as steps of a stairway; also, stones in a stream used for crossing. [1]

…while at Calais in 1474 we find 40 ‘steppyngstounes’ bought for the stairways of the town. [2]

2. n. [chiefly Pythonic] A package that provides iterators for advancing from start to stop, subject to algorithms that depend on user-defined value or error.

• Documentation: https://pages.nist.gov/steppyngstounes/en/latest

• Discussion: https://github.com/usnistgov/steppyngstounes/discussions

• Source code: https://github.com/usnistgov/steppyngstounes

• Bug reports: https://github.com/usnistgov/steppyngstounes/issues

A steppyngstounes control loop replaces an iteration loop like

for step in range(steps):
    do_something(step)

It can be as simple as

from steppyngstounes import FixedStepper

for step in FixedStepper(start=0., stop=totaltime, size=dt):
    do_something(step.size)

    _ = step.succeeded()

or a more elaborate combination of checkpoints and adaptive steps

from steppyngstounes import CheckpointStepper, SomeStepper

old = initial_condition
for checkpoint in CheckpointStepper(start=0.,
                                    stops=[1e-3, 1, 1e3, 1e6]):

    for step in SomeStepper(start=checkpoint.begin,
                            stop=checkpoint.end,
                            size=checkpoint.size):

        new = do_something_else(step.begin, step.end, step.size)

        err = (new - old) / scale

        if step.succeeded(error=err):
            old = new
            # do happy things
        else:
            # do sad things

    save_or_plot()

    _ = checkpoint.succeeded()

Steppyngstounes requires numpy, scipy, and pytest. Tests can be run with

pytest