Quote from: BloodyRookie on January 15, 2014, 06:20:04 AM

Quote from: gimre on January 14, 2014, 09:49:45 PM

My code is finally working uff, took me a lot to figure out how to do that is_negative crap in my representation.

So what's the logic behind is_negative?

I've actually partially* answered to that in code flaws thread:

Quote from: gimre on January 14, 2014, 01:35:05 PM

Quote from: BloodyRookie on January 13, 2014, 06:12:23 PM

Can you please ask that guy what the reasoning behind the strange is_negative(long10 x) function is? It's kind of hard to understand.

I'm also interested in this.
a) why there is is_overflow at all... (I thought it'd be simpler to have element of long10 have always reduced mod q....)
b) the second part is magic, as there shouldn't be something like "negative", so I assume job of that xor is to split values into two groups... (why?)

(edit: added is_negative, snippet)

Code:

/* checks if x is "negative", requires reduced input */
private static final int is_negative(long10 x) {
return (int)(((is_overflow(x) || (x._9 < 0))?1:0) ^ (x._0 & 1));
}

I might shed some more light upon that, but probably not today (UTC)

edit:
Oh, P.S.

I'm getting quite terrible results from node.js - last time I checked they were 10 times worse than ones from the browser...
I would appreciate if anyone would share his (her?) results from within the browser