Should uniform(-real.max, real.max) be inf?

[Ali Çehreli]

On 03/01/2012 02:52 AM, Magnus Lie Hetland wrote:
 > What's the preferred way of generating a random floating-point number in
 > the range of a given floating-point type? We have uniform!T() for
 > integral types, but nothing similar for floats? And uniform(-real.max,
 > real.max) (possibly tweaking the limits) seems to only return inf, which
 > isn't terribly helpful.
 >
 > What's the standard thing to do here? I could just use
 >
 > uniform(cast(T) -1, cast(T) 1)*T.max
 >
 > I guess (for some floating-point type T). Seems to work fine, at least.
 >
 > Am I missing the obvious way to do it?
 >

I recommend reading this page:

   http://dlang.org/d-floating-point.html

Especially the ASCII graph there is very interesting. The number of 
distinct values between T.min_normal and 1 are equal to the distinct 
values between 1 and T.max.

Since there are also sub-normal values between 0 and T.min_normal, it 
may make sense to use the range [T.min_normal, 1) and scale the result 
from there. But I haven't tested whether the distinct values in that 
range are equally distributed.

Ali