Script Definitions: don't use `arange`

[Tom-Willemsen]

Issue Description

https://github.com/search?q=repo%3AISISComputingGroup%2FScriptDefinitions%20arange&type=code

replace usage of np.arange with another suitable function

Note that this will either need:

• Users to specify start, stop, num rather than start, stop, step and use np.linspace
• Calculate num based on step as a bound, so the actual step may be less than the specified step size.
• Use arange-like behaviour but include stop if it's within 1% of adding step to start N times, measure it separately otherwise (this is roughly what diamond do for example)
• Some other option (discuss with scientists)

Acceptance Criteria

• np.linspace or another suitable function used in preference to np.arange

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[FreddieAkeroyd]

We could provide the scientists with our own generator that takes both (start, stop, step) or (start, stop, num) and "does the right thing" and they then use this and not worry about linspace / arange?

[Tom-Willemsen]

For reference, diamond have logic that looks something like "if end point would be within 1% of adding step to start N times, include it, otherwise don't". We may wish to implement something similar.

Have a look in other general/numeric python packages for similar functionality before implementing this ourselves.