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Hi,
I'm trying to read in a number containing 1billion digits.
The number is stored in a simple txt file (~950mb) and since it's the only value, which needs to be read in I pipe it using ./bla <number.txt.
However, the prog quits while it's still reading it in.
The code of the program itself is fine.
Any suggestions on what to do?
Maybe there is no type that have limit up to 1 billion digits?
what are you needing to do with this number... cause if u just need to read it into your program you could split it up into a vector of strings, each element holding the max characters a string can hold?
Hope this helps
I'm using GMP and the variable is of type mpf_class.
Even if it was too big, shouldn't it assign 0 to it and then exit the prog(since the number has to be bigger than 1),
as it does if you cin 22222222222222 for example for an int?
I'd like to calculate its primefactors.
Post your "reading it in" code. cin's probably freaking out. 1 billion digits. Sheesh...
mpf_class n;
cin >> n;
that's all.
Perhaps, read up to a certain point. Store that in a temp container, read some more, then append , repeat until the end. It might work...:eek:
probably there is some buffer overflow in the mpf_class's operator>>
try to wrap the >> in the try/catch block and see it...
well, mpf_class needs a parameter for the precision you want, have you done that?
You'd need to set it to over 3.3 billion bits of precision to represent it exactly.
Of course, you could just always read in the first 20 digits, discard the rest, and declare it accurate enough ;)
I've tried setting the precision to 3.3billion as suggested, but then it just segfaults, so I tried it with 3.3million.
I've also wrapped >> in a try/catch, but it still just quits, doesn't print an error.
> simple txt file (~950mb)
You do have got well over 1GB of RAM on you computer, right?
If you can factor a number that large, these guys will probably pay you quite handsomely.
2GB DDR2 and 2GB swap.Quote:
Originally Posted by joni
If that's not enough for the calculations itself, that's fine, but it should be enough to read it in.
Out of curiosity, how did you create a text file with so many numbers? Did you use an infinite loop then write that? Or did you copy and paste in notepad or something?
I generated the first digit randomly from 1-9 and for the rest a loop generating random numbers from 0-9,
cout'ed every single one and tee'd it into number.txt. Not very efficient but simple.