On Thu, 9 Dec 2004 [EMAIL PROTECTED] wrote:
This is nothing to do with integers: 1e18 and 11 are doubles here.
It is a result of rounding error: 1e18/11 is not representable accurately, and this should have been a warning to you that your calculations were unreasonable.
It was -- the poster originally asked about large integer representations and said he was planning to use other software for large integers.
At the time I said that the fact %% didn't give some sort of error or warning was a bug, and was planning to return either a warning or NA or NaN if
abs(x1)>1/.Machine$double.eps
-thomas
The C code is
double myfmod(double x1, double x2) { double q = x1 / x2; return x1 - floor(q) * x2; }
We can improve the answer, but what you are doing is fundamentally flawed and it is hard to detect whether rounding error has affected this. A warning rather than an error seems appropriate.
If you really want to do things like this, try the gmp package (which seems to give the wrong answer here) or a more appropriate calculator.
On Thu, 9 Dec 2004 [EMAIL PROTECTED] wrote:
R Developers,
1000000000000000000 %% 11 [1] -32
I now understand that integers cannot be larger than .Machine$integer.max, but because the above produces a result than is patently wrong instead of an error, I'm reporting this as a bug.
-- Brian D. Ripley, [EMAIL PROTECTED] Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595
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