"Premature optimization is the root of all evil."

Your proposal sounds complicated and incompatible with the existing daily
summaries. You would have to replicate a lot of what it already does.

Make it work first, then worry about making it fast. You don't know yet
whether the calculation will take a long time.



On Wed, Jan 19, 2022 at 9:38 AM Seth Ratner <[email protected]> wrote:

> Your Phenology extension is actually what got me thinking about how to
> implement the chilling hours in a more generic way, such that more than one
> metric (or one set of temperature thresholds) can be used.
>
> The "simplest" way that came to mind was using some sort of modified Daily
> Summary table in the database. I haven't yet figured out how WeeWX
> populates those tables, but if the columns and calculation methods are
> customizable, then the daily (or nightly) data could be compiled at the end
> of the day and loaded into the table. That way every time you want to
> display the information, it's just a straight query from that summary
> table, rather than running the calculations every time for every archive
> entry. This also allows for multiple calculation methods, all stored in the
> summary table.
>
> So as an example, at the end of the day, whenever WeeWX normally populates
> the summary tables, this new extension could run multiple algorithms (one
> for basic chill hours, one for the Utah Model, one for the phenology table
> on your website, etc) and store the resultant value in the respective
> column (one for Utah, one for basic, one for phenology, etc) in the new
> daily summary row for this extension. No new specific types are required in
> the loop or archive packets, so the processing power is only required once
> per day. When the data is viewed, it is only pulling values from a table
> rather than doing the calculations each time.
>
> But I'm not sure such customizations to the daily-table-creation-process
> is possible.
>
> Thoughts?
>
>
>
>
>
>
> On Wednesday, January 19, 2022 at 9:20:30 AM UTC-6 [email protected]
> wrote:
>
>> -----BEGIN PGP SIGNED MESSAGE-----
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>> On Tue, 18 Jan 2022 17:05:33 -0800
>> Tom Deffer <[email protected]> wrote:
>>
>> > Upon reflection, the biggest difference seems to be that
>> > cooling-degree days are weighted by the temperature difference from
>> > the baseline. You just want the total number of hours.
>>
>> > This is best done as an XTypes extension
>> > <HTTP://git hub.com/weewx/weewx/wiki/WeeWX-V4-user-defined-types>.
>>
>> I've fooled around with XTypes for my Phenology extension.
>>
>> * [weewx-phenology](HTTP://LacusVeris.com/Phenology) — Growing
>> Degree-Days development models for various insect pests, showing
>> when to apply control strategies to minimize crop damage.
>>
>> The Growing Degree-Days calculation(s) are compute-intensive relative
>> to the Cooling Degree-Days calculation. XTypes exposes three entry
>> points that return values: scalar, series, and aggregate. I implement
>> only the "series" entry point, and I keep a running tally of
>> cumulative Degree-Days. It seems that, if I had implemented
>> "aggregate," each cumulative step would have meant recalculating
>> previous steps at factorial cost, but that's just me.
>>
>> I agree the Chilling Hours calculations seem relatively simple, but
>> never let it be said that researchers in the Life Sciences can leave
>> any particularly elegant concept uncluttered. Here is a more or less
>> grammatical overview of various kinds of Chilling Hours calculations.
>> You may overlook the Climate Change hysteria at the end. The Utah
>> method obviously requires quite a few machine cycles, but matching the
>> Queensland method's curve might require quite a few more.
>>
>> * [Chill Hours and Fruit
>> Trees](https://practicalprimate.com/chill-hours/) — Many deciduous
>> fruit trees will not give you the fruit yields you want unless your
>> property receives adequate chill hours. But what are chill hours and
>> why are they so important?
>>
>> ... so both Chill Hours and Growing Degree-Days potentially challenge
>> WeeWX's data collection, calculation, reporting, and image generation
>> capabilities. I developed a kludge to handle Growing Degree-Days
>> because treating orchard insects and disease is a season-to-season
>> battle and many treatments depend on such calculations. I am not so
>> interested in Chill Hours because that has more to do with orchard
>> siting and choice of cultivars, which tend to be one-off decisions.
>> However, Chill Hours (in whatever manifestation) does keep coming up
>> here and on the other discussion group I frequent. Perhaps this is
>> due to ongoing Climate-Change concerns.
>>
>> * [Growing Fruit](https://growingfruit.org/search?q=chill%20hours)
>>
>> I wonder whether I have gone down the right chute with the Phenology
>> Extension's Growing Degree-Days calculation and imaging capacity.
>> Does adding Chill Hours call for a more general approach?
>>
>> I sadly fear the appetite for reporting Chill Hours does not
>> necessarily imply the desire or ability to configure WeeWX to do the
>> appropriate calculations or interpret the results. These are not
>> straightforward things.
>>
>> - --
>> .. Be Seeing You,
>> .. Chuck Rhode, Sheboygan, WI, USA
>> .. Weather: http://LacusVeris.com/WX
>> .. 15° — Wind WNW 22 mph — Sky mostly clear.
>>
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>> UuoSAJ4kvvWrCWqDkEZ8tl2yDzAPXU3LnQCeO5z01CamBSnFAr677iJNzwgf15U=
>> =aptL
>> -----END PGP SIGNATURE-----
>>
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