LAE

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Originally posted by: ejones

I need to be able to keep values in variables alive between records. I understand that usually I do not, but sometimes it is necessary.

The Agg node does this internally. And it assumes that the only operations that can be used are sum(), count(), and groupString(). Maybe I missed some of these functions but the point is that I need to be able to write my own grouping functions.

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Originally posted by: tczotter

In Brainscript this is pretty easy.

By the way, those macros work in filters, too. The only difference between Filter and Agg is that they only get initialized once in a Filter, whereas in Agg they get initialized once per group.

Of course, an Agg with a Group By that is a constant (such as true) behaves like a filter.

I'm attaching a demo graph.

If there's a specific situation that isn't obvious, come back.
Attachments:
DemoCustomAgg.brg

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Originally posted by: ejones

Thank you very much for this answer. The example is very detailed and has everything I needed. It is much easier than I expected it to be.