FAQ
Hi, all.

I am one of translator of Python document.
But I am not good at English well.

I can't understand one sentence in:
http://docs.python.org/library/difflib.html#difflib.SequenceMatcher.quick_ratio
This isn?t defined beyond that it is an upper bound on ratio(), and is faster to compute.
I see that quick_ratio() calculates upper bound of ratio().
But I can't get what "this isn't defined beyond that" means.
May someone explain this in easy sentence for me?

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•  at May 6, 2010 at 3:00 pm ⇧

INADA Naoki <songofacandy at gmail.com> writes:

I am one of translator of Python document. But I am not good at
English well. I can't understand one sentence ...
This isn?t defined beyond that it is an upper bound on ratio(), and
is faster to compute.
The word "bound" works like this: a "bound" or "boundary" means a limit
or edge, so often it gets used in math like this:

"I am not sure what the exact value of 'pi' is, but I have done some
work and established a lower bound of 3.0 and an upper bound of 3.2
for its true value."

This means, more simply, that 'pi' lies "between 3.0 and 3.2", but math
people have the specific names "lower bound" and "upper bound" for the
limits that they work out for the value of an unknown or difficult-to-
compute number.

So when 'quick_ratio()' claims to return an "upper bound on ratio()", it
means that it returns a number that 'ratio()' is guaranteed to be "less
than"; it sets, in other words, an upper limit on what the actual value
of 'ratio()' might be.

So if 'quick_ratio()' returns 0.8, it means that 'ratio()' itself might
be 0.8, or 0.6, or 0.003, or 0.00062, or even 0; that is, it might be
any permissible ratio value (they run from 0 to 1) that is not more than
0.8 because 'quick_ratio()' has done some checking and is sure that the
actual 'ratio()' is less than or equal to 0.8.

So did my English make the docs any clearer? Or am I just as confusing? :-)

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Brandon Craig Rhodes brandon at rhodesmill.org http://rhodesmill.org/brandon
•  at May 6, 2010 at 3:06 pm ⇧

On May 6, 2010, at 10:48 AM, INADA Naoki wrote:

Hi, all.

I am one of translator of Python document.
But I am not good at English well.

I can't understand one sentence in:
http://docs.python.org/library/difflib.html#difflib.SequenceMatcher.quick_ratio
This isn?t defined beyond that it is an upper bound on ratio(), and
is faster to compute.
I see that quick_ratio() calculates upper bound of ratio().
But I can't get what "this isn't defined beyond that" means.
May someone explain this in easy sentence for me?
I think it means that the implementation of quick_ratio() is not
defined in a lot of detail, except to say that the function will
return a value that is an upper bound of the value returned by
ratio(). So the value returned by ratio() will always be less than or
equal to the value returned by quick_ratio(), and quick_ratio() is
faster than ratio(). real_quick_ratio() has a similar relationship to
quick_ratio().

Doug
•  at May 6, 2010 at 3:27 pm ⇧
Thank you, Branodn and Doug for quick reply!

The word "upper bound" is also used in Japan with mathematics.
I think it means that the implementation of quick_ratio() is not defined in
a lot of detail, except to say that the function will return a value that is
an upper bound of the value returned by ratio().

I've got "This isn't defined beyond that" means
"This method is not defined in detail more than".

I've misread that "beyond" means "over the upper bound".
Maybe, "more" is easier than "beyond" for non-native English

Thank you very well.
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•  at May 9, 2010 at 2:19 pm ⇧

On May 6, 2010, at 11:27 AM, INADA Naoki wrote:

Thank you, Branodn and Doug for quick reply!

The word "upper bound" is also used in Japan with mathematics.
I think it means that the implementation of quick_ratio() is not
defined in
a lot of detail, except to say that the function will return a
value that is
an upper bound of the value returned by ratio().

I've got "This isn't defined beyond that" means
"This method is not defined in detail more than".

I've misread that "beyond" means "over the upper bound".
Maybe, "more" is easier than "beyond" for non-native English
I agree that the current English phrasing is confusing to non-native
speakers. You should open a ticket in the tracker and ask for that
text to be clarified.

Doug
Thank you very well.
--
_______________________________________________
Doc-SIG maillist - Doc-SIG at python.org
http://mail.python.org/mailman/listinfo/doc-sig
•  at May 11, 2010 at 11:01 am ⇧

Doug Hellmann wrote:
I've got "This isn't defined beyond that" means
"This method is not defined in detail more than".

I've misread that "beyond" means "over the upper bound".
Maybe, "more" is easier than "beyond" for non-native English
I agree that the current English phrasing is confusing to non-native
speakers. You should open a ticket in the tracker and ask for that text
to be clarified.
Or, as Georg pointed out recently, email docs at python.org mentioning the
problem (tracker is best, but an email to the docs address is better
than not reporting it directly at all).

Cheers,
Nick.

--
Nick Coghlan | ncoghlan at gmail.com | Brisbane, Australia
---------------------------------------------------------------
•  at May 11, 2010 at 11:14 am ⇧
I've posted it as a bug 8686.
http://bugs.python.org/issue8686#

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