File structure¶

The package consists of only two modules: spacq.iteration.sweep which contains SweepController, and spacq.iteration.variables which defines input, condition and output variables. Together, these modules can be used to provide iteration over a set of variables.

Sweeping¶

spacq.iteration.sweep.SweepController goes through a process of several stages, as crudely drawn in its docstring:

                                                        conditional_dwell
                                                           v       ^
init -> next -> transition -> write -> dwell -> pulse -> read -> condition -> ramp_down -> end
^       ^                                  |_____________^           |             |
|       |____________________________________________________________|             |
|__________________________________________________________________________________|

The ordering is approximately linear, but with some loops and skips:

• If no pulse program is defined, the pulse stage is skipped.
• If at least one of the changed order’s condition variables evaluate to false, condition heads to conditional_dwell. Otherwise, if more items remain to be iterated over, condition heads to next.
• If the sweep is continuous, ramp_down restarts it instead of finishing it.

Those steps which deal with accessing resources (transition, write, read, ramp_down) do so in parallel, using as many concurrent threading.Thread objects as necessary.

The sweeping process can be interrupted at any time for many reasons; some of these include: user error, device error, and the user pressing the “Cancel” button. In the case that it is interrupted, the sweep simply proceeds to either the ramp_down or the end stage, depending on whether the interruption is fatal. In the case of a fatal interruption, the ramp_down stage cannot be expected to succeed (for example, if writing to a resource failed), so it is skipped.