K‮ly‬e @khird@qoto.org

Is there a well-known name for the multiplicative equivalent to the absolute value function?

The absolute value function f(x), for real x, is the identity operation f(x) = x for x greater than the additive identity (zero), but it's the additive inverse f(x) = -x for x less than the additive identity.

I'm interested in the function g(x) over the positive reals that is the identity operation for x greater than the *multiplicative* identity (one), but the *multiplicative* inverse x⁻¹ for x less than the multiplicative identity.

I don't need g to take on any particular value for negative x, much less complex x, but I think the most natural extension would be that the function's rotationally symmetrical about the origin (an odd function, so g(-x) = -g(x)).

@mitch I'm of the opposite opinion. It's an entire continent's worth of cultures - it's a daunting task and *should* be hard to learn. We've made it artificially easy by speaking of "the Great Spirit", as if we could talk about "the thunder god" while mashing together stories of Thor, Zeus, and Jupiter to say anything intelligent about pre-Christian European religion.

@mitch Good luck! I made the Ubuntu -> Debian change a while back, but I found being that far behind the bleeding edge to be difficult in its own way - it was hard to find documentation and support for such old versions of the software. Couldn't make it stick.

@Clementulus good insight, thanks! To my mind, it's actually *fewer* moving parts to worry about, on account of the fridge not needing a compressor/refrigeration circuit, plus you'd get the benefits of having the heat pump on your water heater without adding another set of moving parts. That cuts most of the complexity out of the fridge, which I'd think would partly offset the costs of installation.

Taking the current fad for heat pumps one step further, is there a reason we couldn't have other appliances hooked into circuits of cold/hot/return pipes carrying a refrigerant or coolant throughout the house? For example, your refrigerator or water heater would be just a passive heat exchanger with a thermostat to open and close a valve when necessary.

In the case of a refrigerator, this would mean that in summer, the heat gets pumped to the water heater or directly outdoors, rather than getting pumped into your kitchen by the refrigerator and then pumped outdoors by the A/C. And in winter, the waste heat gets pumped into your HVAC to heat the whole house and not just the kitchen.

In the case of the water heater, this would mean that in summer, you're scavenging heat into your water that would be dumped outdoors by a traditional A/C. In winter, you'd be sucking heat in from the outdoors and from your fridge, and only having to run a heating element to make up the difference when necessary.

Diagrams to illustrate are mine. Yes I know the heat exchangers would be counter-current, but I tried to draw them as simply as possible.

@mitch good luck man

@mitch been getting worse as I get older honestly. I feel like the hot head of a teenager is supposed to cool off and leave you more cerebral as you age, but I think I experienced the reverse.

@pemensik thanks, that seems to have the options I need. I'll have to plan this out to minimise the risk of knocking myself off the internet and the disruption/downtime of the change and possible outage.

Anyone know if it's possible to generate #DNS64 entries locally on #OpenWRT? The service I use (at 2606:4700:4700::64) seems to be misbehaving, but DNS is reported to be fully functional on the Cloudflare status page. It seems like #dnsmasq ought to have all the information it needs to generate an AAAA record corresponding to the A record, so I could just use standard #DNS upstream, but I can't figure out how to do it.

@mitch huh. I thought I knew about the Web of Trust, but the thing I remembered was completely different and mostly related to PGP keys.

@mitch Here's an ACK from qoto.org at 2111 UTC. At time of writing it says the post was 35 minutes old. I voted a couple minutes ago.

@mitch I remember "dancing" to this at maybe five years old - essentially just flailing around as fast as I could to keep up with the extremely rapid pace of the syllables.

@mitch NASA does lots of stuff that isn't STEM, though. They have their own logistics guys (super guppy), their own detectives and auditors (inspector general's dep't), enough management/HR staff to sink a battleship, ...

@dgar There used to be a huge statue of Jesus nearby, made of some kind of foam moulded onto a steel frame. Its appearance led to the moniker "Big Butter Jesus" as well as [a song of the same name](https://www.youtube.com/watch?v=XWF8_rZnwLA). But it's "used to be" because it turns out that flammable foam on a sixty-foot piece of metal doesn't play well with thunderstorms.

The insurance company classified its demise as an "act of God."

@mitch pretty much every other genre has humans as the first/only sapient species (or at best in fantasy they share the role with short-humans, or pointy-eared-humans, etc. that's a totally different race honest we swear). Let sci-fi go against the grain! ;)

@freemo in cooking, oils are generally triglycerides - we aren't really adapted to consume raw hydrocarbons. And even a low molecular weight species like triformin already has a boiling point over 250C.

@freemo If you're not set on a paint, you might try a wood dye. It sits in the sweet spot between fully opaque paints and natural-tone stains, in that it soaks into the wood and leaves the grain visible but comes in vivid colours. The wear resistance comes from the fact that in penetrates the wood to a certain depth, so you'd have to physically abrade the wood down by a millimetre or so before you start seeing the undyed part.

See rockler.com/transtint-dyes for an idea of the kind of colours you could get. Reminds me of shopping for fountain pen ink!

@freemo a bridge? I'm not sure I understand the description correctly but I'm picturing a bunch of "pilings" placed side by side and a "deck" that lies across the top of all of them.