How to use infinities with BC Math in php?

Asked Jun 13 '12 at 14:04

Active Jun 13 '12 at 14:11

Viewed 206 times

I cannot find how to use infinities with BC Math. Let's take something like:

$result = echo bcdiv("1", $divider);

It goes all well until $divider is 0. So you make an exception:

if (!bccomp($divider, "0")) {
    $result = echo bcdiv("1", $divider);
}
else {
    $result = INF;
}

The problem is that $result gets computed as "0" in future calculations. I can set $result as an arbitrary large number, but that destroys the concept of exact calculations. Also, it will get much slower if I put a too large number in order to get accurate calculations.

Is there a way to overcome this?

edited Jun 13 '12 at 14:11

asked Jun 13 '12 at 14:04

Maxime Michel

1

[The result of `1/0` is not infinity.](http://en.wikipedia.org/wiki/Division_by_zero) – Polynomial Jun 13 '12 at 14:08
It is indeterminate, but the right limit of 1/x at x=0 is infinity and it can often be used for calculations. – Maxime Michel Jun 13 '12 at 14:12
If that doesn't convince you, just forget the division and assume you want to assign infinity to $result. How would you do that in BC Math. – Maxime Michel Jun 13 '12 at 14:14
BC Math doesn't support infinity cases. It simply returns null when an operation would result in infinity or IEEE NaN. – Polynomial Jun 13 '12 at 14:17
1

So no other way than $result = "999999999*snip*9999999"? – Maxime Michel Jun 13 '12 at 14:23
1

Or just `str_repeat('9', 1000);` – Polynomial Jun 13 '12 at 14:35

How to use infinities with BC Math in php?

0 Answers0