Simulating 15C RAN # on 35s

[rprosperi]

(02-15-2015 03:45 PM)Tugdual Wrote:  This is what I understood:
If RND(n) = 0.aaaaabbbbb then \(10^5\)*RND(n) = aaaaa.bbbbb
So this becomes
(15743 + 0.52261) * (aaaaa + 0.bbbbb)
aaaaa*15743 has no fractional part so you can drop it

What Thomas didn't mention (but implied in his code) is that 0.52261 * 0.bbbbb < 1 so you don't need to FP this part but aaaaa * 0.52261 > 1 as well as 15743 * 0.bbbbb > 1 so you need to FP the sum of these two ones first otherwise you will end up with 10 digits in the mantissa of which 5 will be used for IP.

Thank you Tugdual, very clear now. As we've come to expect from Thomas, very insightful and clever. Thanks to both of you!