random() and random(2^31)

[Bill Allombert <allomber@math.u-bordeaux.fr>]

Hello PARI-dev,

random() documentation imply that random() is equivalent to random(2^31)
which is not true. In fact random(2^31) produce usually better results:

? #Set(vector(1024,i,sum(i=1,1024,random()%1024)))
%13 = 1
? #Set(vector(1024,i,sum(i=1,1024,random(2^31)%1024)))
%14 = 172

So either we fix the documentation or we change random() to be an alias
for random(2^31).

Of course there is a more general problem of improving the random number
generator of PARI. (The 172 above is bogus).

Cheers,
Bill.