Re: [boost] boost interval arithmetic

Subject: Re: [boost] boost interval arithmetic
From: Павел Кудан (coodan_at_[hidden])
Date: 2015-01-15 09:01:41

>I fail to see how that is relevant to the discussion of how interval division 
>should be handled.

That is why I did not explain another misconception of same basic / operator of boost interval class.

But hope you are agree that [-inf, inf], which contains all possible numbers from -infinity to +infinity, cannot be empty, at least, at float :)

Now let's see again the official definition of / and /= operators.

>>The operators  / and  /= will try to produce an empty interval if the denominator is exactly zero. If the denominator contains zero (but not only zero), the result will be the smallest interval containing the set of division results; so one of its bound will be infinite, but >>it may not be the whole interval.

Let's see first statement: "The operators  / and  /= will try to produce an empty interval if the denominator is exactly zero."

And let's know what does it mean...

To exclude possible language barrier, let's see the definition of word 'denominator': the expression written below the line in a  common fraction that indicates the number of  parts into which one whole is  divided.

So, in expression A / B, denominator is B.

What is exactly zero interval? It is [0,0]. What is [0,0]? It is single float value, zero.

Is it right?

Now see:

[-1.0, 1.0] / .0

What is the correct result? Of course, [-inf, inf]

What is an official result of interval boost class for this situation.

Empty interval, as we just saw.

So I would like to ask everyone if no misconception with boost interval class exists, how interval, including all possible numbers, [-inf, inf], may be EMPTY?!?