[DISCUSS] Control window width along a summed axis

[FabianHofmann]

What can be improved?

Currently, rolling sums only take a single value for controlling the window.

For a fine-grained control, we need to specify the size of the window summed over per entity. Then, sum_back(x, over=d, within=n) takes a number or an integer parameter, so a window may be a different length. The value likely stays static along dimension d ie. in pypsa terms we don't have different windows sizes per component and snaphot, only per component.

Version

v0.0.0-alpha.13

[FBumann]

Yes, we need that.

[brynpickering]

Agree. Something I found a limitation in the calliope spec already.

[FBumann]

Is this needed in pypsa @FabianHofmann ? If so, add it to the milestine please.

[FBumann]

Prompt: "close the 4 where the feature shipped"

Note

The following content was generated by AI.

Shipped. sum_back(x, over=d, within=p) takes an integer parameter as well as a number, so each entity gets its own window length — operators reference, row sum_back(array, over=dim, within=p).

The two rules this issue asked for are enforced at load, in _check_named_amount (src/math_spec/dimensions.py), and #61 is where they were held to:

• p is refused unless it is dtype: int, because a count of positions is integral.
• p is refused where it is declared over d itself. The message is "a named width that varies along the axis it walks is … declare it over dims 'd' is not one of", which is this issue's "the value likely stays static along dimension d".

A third rule arrived with it: p may not vary over a dim the coordinate does not carry, unless a by= lookup groups into it.

Checked by reading origin/main at 78b0ce1. The suite was not run for this close.

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Generated by Claude Code