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? :-)