On Thursday, December 7, 2017 at 1:10:25 AM UTC+1, AK wrote:
> Użytkownik "slawek" <f...@f...com> napisał:
> >> rand() & 0xFF // ;)
> >
> > Lepiej (rand() >> 4) & 0xff
> >
> > Najniższe bity wywalić.
>
> To prawda, ale oni chcieli "szybciej", a nie "lepiej" :)
> PS: Oczywiscie generalnie to byl zart (no nie tak znow w 100%:)
>
> AK

Generator Fibonacciego też można napisać w 10 minut na
kolanie i, jak na razie, przeszedł kilkanaście początkowych
diehardera nawet na m=30. Generowanie liczb jest ekstremalnie
szybkie, nie zawiera nawet ifa. Niestety nie wiadomo czy dla
innych zarodków też zachowa się tak samo dobrze :/ I drugie
niestety: poniższa implementacja wymaga ponad 16k bajtów ram.

Kod:
class FibRnd {
private:
unsigned int a,b,c;
unsigned int *x;
unsigned int max;

public:
FibRnd(unsigned int seed) {
max = 1<<12;
a = 0;
b = 16;
c = max-1;
x = new unsigned int[max];
for( unsigned int i=0 ; i<max * 4 ; i++ ) {
x[i%max] <<= 4;
x[i%max] ^= seed = ((seed * 359ull + 3733ull) % 1057767ull);
}
}
~FibRnd() {
delete[] x;
}
unsigned int operator ()() {
a = (a+1)&(max-1);
b = (b+1)&(max-1);
c = (c+1)&(max-1);
return x[c] = x[a] + x[b];
}

};

int main( int argc, char *argv[] ) {
FibRnd rnd((unsigned int)time(NULL));
while( true ) {
unsigned char x[N];
for( int i=0 ; i<N ; i++ )
x[i] = (unsigned char)rnd();
fwrite( x , 1 , N , stdout );
}
return 0;
}

Test:
time ./frnd | dieharder -a -m 30 -g 200
#===================================================
==========================#
# dieharder version 3.31.1 Copyright 2003 Robert G. Brown #
#===================================================
==========================#
rng_name |rands/second| Seed |
stdin_input_raw| 3.00e+07 |2482448351|
#===================================================
==========================#
test_name |ntup| tsamples |psamples| p-value |Assessment
#===================================================
==========================#
diehard_birthdays| 0| 100| 3000|0.29234458| PASSED
diehard_operm5| 0| 1000000| 3000|0.51398474| PASSED
diehard_rank_32x32| 0| 40000| 3000|0.36767415| PASSED
diehard_rank_6x8| 0| 100000| 3000|0.69227346| PASSED
diehard_bitstream| 0| 2097152| 3000|0.30960016| PASSED
diehard_opso| 0| 2097152| 3000|0.85888419| PASSED
diehard_oqso| 0| 2097152| 3000|0.67207083| PASSED
diehard_dna| 0| 2097152| 3000|0.00012554| WEAK
diehard_count_1s_str| 0| 256000| 3000|0.51597335| PASSED
diehard_count_1s_byt| 0| 256000| 3000|0.26197695| PASSED
diehard_parking_lot| 0| 12000| 3000|0.17469806| PASSED
diehard_2dsphere| 2| 8000| 3000|0.54418532| PASSED
diehard_3dsphere| 3| 4000| 3000|0.87789531| PASSED
diehard_squeeze| 0| 100000| 3000|0.26815462| PASSED
diehard_sums| 0| 100| 3000|0.00000000| FAILED
diehard_runs| 0| 100000| 3000|0.01445376| PASSED
diehard_runs| 0| 100000| 3000|0.00537657| PASSED
diehard_craps| 0| 200000| 3000|0.93729302| PASSED
diehard_craps| 0| 200000| 3000|0.34274658| PASSED



Pozdrawiam

P.S.
Nie patrzcie na diehard_sums, bo ten test zawiera błędy.