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Remove fast division test because it is no longer needed and the latest version is actually buggy (thanks to primedigger for spotting this).

master
Mikael Hirki 2013-08-15 22:16:57 +03:00
parent 56072a11c0
commit ee44fbe650
1 changed files with 2 additions and 58 deletions
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60
src/prime.cpp
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@ -514,9 +514,6 @@ unsigned int EstimateWorkTransition(unsigned int nPrevWorkTransition, unsigned i
/* PRIMECOIN MINING */
/********************/
// Number of primes to test with fast divisibility testing
static const unsigned int nFastDivPrimes = 60;
class CPrimalityTestParams
{
public:
@ -530,11 +527,6 @@ public:
mpz_class mpzOriginPlusOne;
mpz_class N;
// Big divisors for fast div test
std::vector<unsigned long> vFastDivisors;
std::vector<unsigned int> vFastDivSeq;
unsigned int nFastDivisorsSize;
// Values specific to a round
unsigned int nBits;
unsigned int nPrimorialSeq;
@ -564,31 +556,12 @@ public:
// Check Fermat probable primality test (2-PRP): 2 ** (n-1) = 1 (mod n)
// true: n is probable prime
// false: n is composite; set fractional length in the nLength output
static bool FermatProbablePrimalityTestFast(const mpz_class& n, unsigned int& nLength, CPrimalityTestParams& testParams, bool fFastDiv = false, bool fFastFail = false)
static bool FermatProbablePrimalityTestFast(const mpz_class& n, unsigned int& nLength, CPrimalityTestParams& testParams, bool fFastFail = false)
{
// Faster GMP version
mpz_t& mpzE = testParams.mpzE;
mpz_t& mpzR = testParams.mpzR;
if (fFastDiv)
{
// Fast divisibility tests
// Divide n by a large divisor
// Use the remainder to test divisibility by small primes
const unsigned int nDivSize = testParams.nFastDivisorsSize;
for (unsigned int i = 0; i < nDivSize; i++)
{
unsigned long lRemainder = mpz_tdiv_ui(n.get_mpz_t(), testParams.vFastDivisors[i]);
unsigned int nPrimeSeq = testParams.vFastDivSeq[i];
const unsigned int nPrimeSeqEnd = testParams.vFastDivSeq[i + 1];
for (; nPrimeSeq < nPrimeSeqEnd; nPrimeSeq++)
{
if (lRemainder % vPrimes[nPrimeSeq] == 0)
return false; // returning here skips the fractional length calculation!
}
}
}
mpz_sub_ui(mpzE, n.get_mpz_t(), 1);
mpz_powm(mpzR, mpzTwo.get_mpz_t(), mpzE, n.get_mpz_t());
if (mpz_cmp_ui(mpzR, 1) == 0)
@ -674,7 +647,7 @@ static bool ProbableCunninghamChainTestFast(const mpz_class& n, bool fSophieGerm
nProbableChainLength = 0;
// Fermat test for n first
if (!FermatProbablePrimalityTestFast(n, nProbableChainLength, testParams, true, true))
if (!FermatProbablePrimalityTestFast(n, nProbableChainLength, testParams, true))
return false;
// Euler-Lagrange-Lifchitz test for the following numbers in chain
@ -791,35 +764,6 @@ bool MineProbablePrimeChain(CBlock& block, mpz_class& mpzFixedMultiplier, bool&
// Allocate GMP variables for primality tests
CPrimalityTestParams testParams(nBits, nPrimorialSeq);
// Compute parameters for fast div test
{
unsigned long lDivisor = 1;
unsigned int i;
testParams.vFastDivSeq.push_back(nPrimorialSeq);
for (i = 1; i <= nFastDivPrimes; i++)
{
// Multiply primes together until the result won't fit an unsigned long
if (lDivisor < ULONG_MAX / vPrimes[nPrimorialSeq + i])
lDivisor *= vPrimes[nPrimorialSeq + i];
else
{
testParams.vFastDivisors.push_back(lDivisor);
testParams.vFastDivSeq.push_back(nPrimorialSeq + i);
lDivisor = 1;
}
}
// Finish off by multiplying as many primes as possible
while (lDivisor < ULONG_MAX / vPrimes[nPrimorialSeq + i])
{
lDivisor *= vPrimes[nPrimorialSeq + i];
i++;
}
testParams.vFastDivisors.push_back(lDivisor);
testParams.vFastDivSeq.push_back(nPrimorialSeq + i);
testParams.nFastDivisorsSize = testParams.vFastDivisors.size();
}
nStart = GetTimeMicros();
// References to test parameters