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Comment by AEVL | Hacker News Reader

Not an off-by-one error—at least not in spirit. Interesting nonetheless.

I expected the article to eventually answer this puzzle:

> The competition started and got through a number of rounds. There were some comments about how the climber on the left always won.

Near the end:

> The kicker is that the out of place hold hasn’t been used in a long time. The climbers have optimised their route such that it is skipped. The same happens to the fourth hold from the bottom. So either being in the wrong place is immaterial to the climbers’ technique as long as they don’t get in the way.

So it seems like the error discovered by the article author should not have conferred any advantage to the climber on the left.

Anyone who can shine light on this matter?

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People are misunderstanding the meaning of an off-by-one error. Suppose the plan states that hold A and hold B need to be 11 holes apart. In the true spirit of the off-by-one error, this can be interpreted in 3 ways:

- either as 11 empty holes between the holds; - as 11 holes, start counting 1 just above hold A; - or as 11 holes, start counting with hold A as number 1.

Another real-life example, is a plumber who tells the construction worker that the distance between the holes for hot and cold water needs to be 15 cm. This was meant to be measured center to center, but the constructor worker interpreted it as the distance from the right side of the first hole to the left side of the second. The result can still be admired in our house, 10 years later.

I might be splitting hairs now. Is not ambiguity the problem in your examples, and not any off-by-one error? If the respective ambiguities were resolved then there should be no off-by-one errors.

Of course use of expressions may vary. My in-spirit-meaning of ‘off-bye-one error’ may differ from yours, and that is fine. (Had it really mattered in a discussion then we would simply agree to find a suitable definition of the expression.)

The climbers had complained about an issue with the belay ropes on the right side that they also fixed.

> A few of the climbers had said that the automatic belay ropes on the right hand lane did not feel right, so the cherry picker was replacing those and not the hold that I had noticed being out of place. The climbers had noticed something wasn’t quite right, but hadn’t said anything about the out of place hold.

It was probably just two separate problems.

>Not an off-by-one error—at least not in spirit. Interesting nonetheless.

Literally it was an off-by-one error. Literally, literal meaning.

I think the poster meant off-by-one doesn’t simply mean a plus or minus one error, like mispricing a $5.99 as $6.99, but instead must be born out of confusion as to whether an origin point is marked as a 1 or as a 0.

> must be born

There are other reasons as well. I think the more common causes are inclusive vs exclusive comparison errors and fencepost.

> must be born

The spelling is off by one. It's "borne"

>The spelling is off by one. It's [not "born" it's] "borne"

the spelling was actually off by e , so you're stilll off by 1.71828...

Off-by-one is not born from the base of the index. It is a general problem a lot of people run into in a lot of different contexts.

It’s for example called “the fencepost problem”: https://betterexplained.com/articles/learning-how-to-count-a...

I agree subtracting or adding one to any number is not the problem. It has to do with counting.

>I agree subtracting or adding one to any number is not the problem. It has to do with counting.

if you are sprint climbing and you put your hand out to grab and you add or subtract the number 1 from where your hand needs to be, it is a problem or contributes to a speed difference.

Perhaps the pieces are placed by counting a number of holes from piece A to piece B? That's a perfect recipe for an off-by-one: at which point relative to piece A do you start counting.

> So it seems like the error discovered by the article author should not have conferred any advantage to the climber on the left.

They might not use the hold by physically touching it, but they might still use it as a visual indicator of where the other holds are in relation. These competitors are used to the same layout for many years. If there is a slight misrepresentation it can surely put them off.

It's true that modern competitive speed climbers don't use that hold. The collective optimization of the route is hilariously serious (it's an olympic sport after all) and the different optimizations have names, like 'The Tomoa Skip'.

But I think it's possible that 'extra' holds are potentially like 'junk' DNA. People fall into the trap of thinking that DNA is useless if it's never transcribed, but we know that's not actually the case. Non-expressed DNA can do things like alter binding affinity for neighboring sequences, affecting how often those neighboring sequences are expressed. I think it's possible that climbers are taking in a lot of information subconsciously as they sprint through this route in order to mike very small adjustments. The position of surrounding holds, even ones they never touch, could very well be a part of that information stream. They're fighting over hundredths of a second, so even a very small effect could be meaningful.

It may not be a fencepost error, but I think it's still off by one.

Even if the out of place hold were used, would you then conclude it to be causal? I still wouldn't rule out coincidence. Many discoveries happen as a result of investigating spurious patterns.

Also the author rules out psychology, but I wouldn't, especially since there were multiple confirmed errors in the route preparation, which I expect could reduce one's trust in the fairness of the competition. In the moment, I might start to wonder, "If one hold was out of place, why not more? Is anyone even checking this?" even if untrue / unlikely.

I’ve never been a competitive speed climber, but I do understand that part of the process of precision is having cues for e.g. body position. So the fact that it’s never actually touched is not necessarily the red herring it seems to be. Racecar drivers cue off of trackside landmarks to get their brake timing right, for instance.

Certainly, the rope feel is a much more significant factor, since the feel of the rope tugging on your harness is a non visual part of your body position feedback (maybe “I know that I’m going fast enough/pulling hard enough if I’m outracing the rope retraction rate”).

They run the whole 15 meter up in about 5-10 seconds (quite amazing to watch: https://m.youtube.com/watch?v=8O4g8JmWn9E ). At that speed, a small disturbance from the path they internalized means that they need to switch back to thinking which will take them out of their flow.

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