In this case, you just need either one of the values converted to a BigInt, and big(2)^32 is marginally more efficient than 2^big(32), since it allocates one less BigInt.
Also, wouldn't typemax(Int)/typemax(Uint) be what you want here? On 12 January 2014 14:29, Ivar Nesje <[email protected]> wrote: > I really agree that this is a mistake that is easily made. There is a FAQ > answer that explains why we use integer arithmetic with silent overflow. > > I think Julia would benefit from a simpler way to express numerical > constants with type than to first create a Float64 / Int32/64 and then send > to constructor, but I have not (yet) found a syntax to suggest that would > get approval. > > One idea might be to implement a @big macro that would allow you to write > @big(2^32) > and it would be automatically translated to > big(2)^big(32) > > The problem is that it will not work (in a sensible way) for floating point, > because the macro will not be able to see the string representation, but the > closest Float64 version. This means that 0.1 will be > 1.000000000000000055511151231257827021181583404541015625e-01 instead of > 1.000000000000000000000000000000000000000000000000000000000000000000000000000002e-01 > > kl. 17:02:25 UTC+1 søndag 12. januar 2014 skrev Földes László følgende: >> >> This little piece of code tricked me: >> >> if value < big(2^32) >> println("Finished!") >> break >> end >> >> The println was never executed and couldn't find the problem for about 3 >> minutes when I tried it on a 64 bit OS, where it worked. >> The problem is that on 32-bit OS 2^32 equals to zero. I'm just getting >> used to Julia internals and it is not really a problem if it is apparent, >> but I clearly need more time with the language to spot these kind of error. >> >> if value < big(2)^big(32) >> println("Finished!") >> break >> end >> solve this. But this is ugly and it looks like something that can be >> automated. >> >> is there any coding style that can prevent this error? I would better >> receive an overflow error (if it is turned on with a flag to the Julia >> executable maybe) than a silent, never running piece of code.
