Number Bug

[Andy01]

Could someone please check this for me - It could be the LiveCode version I'm using

put (10000000000000000 + 1) = 10000000000000000 ? -- incorrect
put (10000000000000000 + 2) = 10000000000000002 -- correct

No wonder the numberFormat function doesn't work properly There's heaps more

put 100000000000000000000000 * 1 = 99999999999999991611392 ? -- incorrect

[jmburnod]

Hi Andy,
I get same results (LC 9.6.5)
Best regards
Jean-Marc

[Andy01]

Hi Andy,
I get same results (LC 9.6.5)
Best regards
Jean-Marc

Thanks Jean-Marc, wow it looks like the LiveCode programmers need to go back to the drawing board and also learn math at the same time Their engine is running on 3 cylinders

[jmburnod]

Ok this is strange but we maybe forget something.
First time i work with a so large number

[SparkOut]

There are definitely limits in the way computers handle floating point integers with high numbers of digits. This cropped up a while back, and there was some discussion here about it. I believe it is the same implementation in LiveCode as many other high level languages, and is a factor of hooking into the underlying systems, rather than a shortcoming of the LiveCode programmers. There is a big number maths library coded by Geoff Canyon
viewtopic.php?f=9&t=31793

[Andy01]

Maybe you guys are right and I'm wrong. But I don't see what the problem is because it should only be a memory problem not a math problem. When you add two numbers together all your doing is just adding units and then carrying over if needed.

[richmond62]

I had a go with those examples in LC 9.6.3 on MacOS 12.2 and
the results were exactly as per the OP.

I cannot get over-excited about that as I rarely count beyond 1114109 ( Hex 10FFFD) as that's
about as far as I have to go with Unicode fonts.

Oddly enough: HyperCard got the first one right:
-

-
Mind you, I am rather fond of the Hex number EFFED0FF

[SparkOut]

The problem isn't to do with memory, it's that numbers are handled in the engine with a limitation on the number of bits so you lose precision with very large numbers.

https://quality.livecode.com/show_bug.cgi?id=15775

It is discussed in detail in this thread viewtopic.php?f=7&t=25132

[dunbarx]

This is an inherent limitation, and has nothing to do with LC. You cannot do arithmetic operations with more than about 17 decimal digits. There is lot of discussion on the forum about this running for a decade.

I made a function, "longAdd", that added numbers of any length when I first started playing with LC. Never needed to, just because. But Hermann made functions for all four operations, and they are in the forum somewhere.

I miss him.

Craig

[FourthWorld]

While it's true that this is more of a computer science thing than a LiveCode thing, if we can account for it in script why can't that script be included in the engine?

A bug report becomes a feature request.

[dunbarx]

All true, that 17 digits ought not to be anyone's limit, But know that such a value is the equivalent of measuring the diameter of our galaxy to a precision of about a mile, or the diameter of the solar system to a tenth of a millimeter.

Craig

[richmond62]

You cannot do arithmetic operations with more than about 17 decimal digits.

Then how did HyperCard manage that?

[dunbarx]

Richmond.

I don't recall that it did. HC also was in thrall to internal limits. Should I recheck?

Craig

[richmond62]

Pictures rarely lie.

[dunbarx]

Richmond.

You are the man when it comes to pictures.

But HC has the same limitation that LC does. Any calculation that runs past 16 or 17 digits fails. I recall that Apple used "SANE", a protocol that may or may not still be used today, and that is where the , limitation lies.

Craig