[R] 64 bit R double precision

[Peter Dalgaard]

Paul Emberson wrote:
> Hi,
> 
> If R is compiled for a 64 bit platform, does the double data type make 
> use of the additional precision or is it set at a fixed length?

No. Double is double, 64 bits, although sometimes 80 bits when things 
are kept in registers. However, even though the FPU is identical between 
64 and 32 bit machines, you do not in general get the same results, due 
to tricks played by optimizing compilers.

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