unsigned long Primer::calculatePrime(unsigned long num)
{
if (num > MAX_PRIME_NUM)
{
std::cout << "Number to big, max is " << MAX_PRIME_NUM << std::endl;
return 0;
}
if (num >= foundPrimes.size())
{
std::cout << "Prime #" << std::setw(10) << num + 1 << " not known. Calculating from #" << std::setw(10) << foundPrimes.size() << std::endl;
try
{
if (num >= MAX_PRIME_NUM / 2)
{
foundPrimes.reserve(MAX_PRIME_NUM);
}
else
{
foundPrimes.reserve(num + 1);
}
}
catch (std::bad_alloc& ex)
{
fprintf(stderr, "Failed to allocate more memory: %s\n", ex.what());
return 0;
}
startTime = std::chrono::high_resolution_clock::now();
try
{
for (unsigned long i = foundPrimes.size(); i <= num; i++)
{
calculateNextPrime(i);
}
}
catch (std::exception& ex)
{
fprintf(stderr, "Failed to calculate prime: %s\n", ex.what());
return 0;
}
}
return foundPrimes[num];
}
/* factorized a number into prime numbers and registers the result in the arrays */
void primeFactorization (int number, int primes[MAX_PRIMES], int instancesCount[MAX_PRIMES], int primesUsed[MAX_PRIMES], int *maxPrimeDefined, int *primesUsedCount) {
int currentPrimeIndex = 0;
#ifdef debug_on
printf("primeFactorization(%d)\n",number);
#endif
while (number > 1) {
if (currentPrimeIndex > *maxPrimeDefined) {
primes[currentPrimeIndex] = calculateNextPrime(primes[currentPrimeIndex-1]);
*maxPrimeDefined = *maxPrimeDefined;
}
while (number % primes[currentPrimeIndex] == 0) {
number = number / primes[currentPrimeIndex];
if (instancesCount[currentPrimeIndex] == 0) {
primesUsed[*primesUsedCount] = currentPrimeIndex;
*primesUsedCount = *primesUsedCount + 1;
}
instancesCount[currentPrimeIndex] = instancesCount[currentPrimeIndex] + 1;
#ifdef debug_on
printf("%d\n",primes[currentPrimeIndex]);
#endif
}
currentPrimeIndex++;
}
}
