The circumference of Earth at the equator is about 40,000 km and the speed of light is about 300,000 km/s. The appropriate division results in about 0.13 s.
That seems to track. The vast majority of requests won’t go half way around the Earth, so maybe halving that time at 0.06 seems like a reasonable target.
It starts from the identifier. At every stage, it outputs a sub-expression which is the “mirrored use” and corresponds to the boxed representation below it. When it reaches the top of the expression, it prints the final type of the expression which is the lone specifier-qualifier list.
As per the screenshot, “arr” is an array of 4 elements. Consequently, “arr[0]” is an array of 8 elements. Then, “arr[0][0]” is a pointer. And so on, until we arrive at the specifier-qualifier list.
It’s a natural observation, but it doesn’t address the floating point problem. I think the author should have said “fast or would accumulate floating point error” instead of “fast and would accumulate floating point error”.
You could compute in the reverse direction, starting from 1/n instead of starting from 1, this would produce a stable floating point sum but this method is slow.
Edit: Of course, for very large n, 1/n becomes unrepresentable in floating point.
Three techniques I’ve used to handle floating point imprecision/error:
1. Use storage that handles the level of scale and precision you need.
2. Use long/integer (if it fits). This is how some systems store money, e.g. as micros, but even though it’s sensical, there is still a limit and a wild swing of inflation may lead you to migrate to different units, then another wild swing of deflation may have you up-in-arms with data loss. Also it sounds great but could be a pita for storing arbitrary scale and precision.
3. Use ranges when doing comparison to attempt to handle floating point error by fuzzy matching numbers. This isn’t applicable for everything, but I’ve used this before; it worked fine and was much faster than BigDecimal, which mattered at the time. Long integers are really the best for this sort of thing, though; they’re much faster to work with.
4. BigDecimal. The problem with this is memory and speed. Also, as far as we know yet, you couldn’t store pi fully in a BigDecimal, and doing calculations with pi as a BigDecimal would be so slow things would come to a halt; it’s probably the way aliens do encryption.
> Texas loses power one time for a week and the redditors will never let it go. Wild how this is still a cringe joke so many years later.
Texas had the most number of power outages between 2019 and 2023 [1].
It wasn't one time. And it's not a joke. Infrastructure weatherization is a very real overlooked (and expensive) investment that still has not taken place.
Those power outages are local, not the Texas grid.
It was one time. I have been in Texas for over 30 years. Besides a local transformer exploding or something and giving me a temporary outage, I've only had the ONE extended outage in that time.
You guys just really don't know what you're talking about.
> In 2011, Texas was hit by the Groundhog Day blizzard between February 1 and 5, resulting in rolling blackouts across more than 75% of the state… Following this disaster, the North American Electric Reliability Corporation made several recommendations for upgrading Texas's electrical infrastructure to prevent a similar event occurring in the future, but these recommendations were ignored due to the cost of winterizing the systems.
> Unlike other power interconnections, Texas does not require a reserve margin of power capacity beyond what is expected. A 2019 North American Electric Reliability Corporation report found that ERCOT had a low anticipated reserve margin of generation capacity and was the only part of the country without sufficient resources available to meet projected peak summer electricity demand.
If I hadn't been reading headlines I wouldn't have even known about the 2011 blackout, and I was definitely here for that. Things were pretty much normal for everyone around me and friends around the state (Houston, Austin, DFW, Lubbock, San Antonio, etc). The Superbowl even went ahead in AT&T stadium. It really wasn't as big of a deal as a lot of internet commenters seem to act like.
I lived in Texas and we never got rolling blackouts for this. We didn't hear about it from family and friends in every major Texas city. Maybe this means 75% of the state by area rather than population? We just didn't drive because much of Texas isn't set up to clear roads and, more importantly, few of our drivers know how to deal with snow and so most get very unsafe to drive around.
The report your wikipedia article cites for 75% says this: "In the case of ERCOT, where rolling blackouts affected the largest number
of customers (3.2 million), there were 3100 MW of responsive reserves available
on the first day of the event, compared to a minimum requirement of 2300 MW." So an eighth or so of Texas' ~25 million population in 2011.
You originally called someone a redditor making a cringe joke for highlighting a serious historical problem. It wasn't clear to me that it was a joke at all, but my impression is that it seemed clear to you that it was a joke.
What if that person has also lived in Texas for 30 years? And what if they had a family member that died during that power grid failure in 2021? I personally would find it quite difficult to communicate to them the nuance of a local problem and a state-wide problem when the end result is the same: no power.
In the future, you might consider approaching an interaction online with more balanced judgement.
Edit: Actually, looking back at the original comment, it's not even clear they're talking about the Texas power outage in 2021. All they said was "Hope they have ample backup power." Seems like a reasonable thing to hope for what might be critical infrastructure.
Woah, that is extremely cool. Very nice work, sir.
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