thiemowmde added a comment.
I'm sorry, but I do not understand that example at all. Where does a 0.4 come
from in your example? 1.4+-1 is internally stored as { amount: 1.4, before:
0.4, after: 2.4 }. This is, when displayed via the formatter, displayed and
later parsed as 1.4+-1. You can say
thiemowmde added a comment.
In https://phabricator.wikimedia.org/T95425#1353657, @daniel wrote:
24+/-10 can be written as 20 (because we don't care about the 4)
This is simply wrong. These are two completely distinct values. But I'm already
repeating myself.
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daniel added a comment.
@thiemowmde: i think this becomes a lot clearer when you think about your
original value being in meter, and you are trying to display it in feet. The we
must apply rounding based on the uncertainty, otherwise we would be introducing
false precision. And if we do this
thiemowmde added a comment.
15+/-1 feet becomes 5+/-1 meter which becomes 16+/-1 feet.
The before and after values are not there to mark irrelevant digits.
There is no such thing as an irrelevant digit in Quantity values. We do have
this in Time, but not in Quantity.
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thiemowmde added a comment.
The rounding is wrong no matter what. 24+/-10 becomes 20+/-10 with the current
formatting. This is not even remotely the same value.
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daniel added a comment.
What rounding would be correct then, and would also work with unit conversion?
I agree that the current output is a bit odd when the uncertainty interval is
included.
24+/-10 can be written as 20 (because we don't care about the 4), but I agree
that writing it as 20+/-10
thiemowmde added a comment.
Separate? How? I don't understand. A formatter that silently manipulates 1.5+-1
to 2+-1 does change the actual value by 66%. You can't argue that such a major
data loss is insignificant.
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thiemowmde added a comment.
Sorry, I have to disagree. There may be a sweep spot where such a formatting
for display is ok, but rounding 1.9+-1 to 2+-1 is clearly **wrong**, at
least in my opinion. These two strings describe two completely different values.
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daniel added a comment.
They are two different intervals, sure. If you however consider the +/- as an
uncertainty, they are nearly the same in the sense that the difference is
insignificant. An uncertainty interval of +/-1 is the explicit statement that
any difference 1 is insignificant.
If
