T shanks_factor(const T n) {
  static_assert(std::is_signed<T>::value, "Must be signed");
  auto find_factor = [n](const T k) -> T {
    const T sqrt_kn = isqrt(k * n);
    T p = sqrt_kn, old_p;
    T q = (k * n - p * p), old_q = 1;
    if (q == 0)
      return k == 1 ? sqrt_kn : 1;
    auto iterate = [&] {
      old_p = p;
      T b = (sqrt_kn + old_p) / q, tmp;
      p = b * q - old_p;
      tmp = q, q = old_q + b * (old_p - p), old_q = tmp;
    };
    for (size_t i = 1; i % 2 || !is_square(q); ++i)
      iterate();
    const T sqrt_q = isqrt(q);
    const T b = (sqrt_kn - p) / sqrt_q;
    p = b * sqrt_q + p;
    old_q = sqrt_q, q = (k * n - p * p) / old_q;
    do
      iterate();
    while (p != old_p);
    return gcd(n, p);
  };
  const T max_k = std::numeric_limits<T>::max() / n;
  for (T k = 1; k <= max_k; ++k) {
    const T f = find_factor(k);
    if (f != 1 && f != n)
      return f;
  }
  throw std::overflow_error("Can't use a larger multiplier.");
}
Exemple #2
0
/// P3(x, a) counts the numbers <= x that have exactly 3
/// prime factors each exceeding the a-th prime.
/// Space complexity: O(pi(sqrt(x))).
///
int64_t P3(int64_t x, int64_t a, int threads)
{
  print("");
  print("=== P3(x, a) ===");
  print("Computation of the 3rd partial sieve function");

  double time = get_wtime();
  vector<int32_t> primes = generate_primes(isqrt(x));

  int64_t y = iroot<3>(x);
  int64_t pi_y = pi_bsearch(primes, y);
  int64_t sum = 0;

  threads = ideal_num_threads(threads, pi_y, 100);

  #pragma omp parallel for num_threads(threads) schedule(dynamic) reduction(+: sum)
  for (int64_t i = a + 1; i <= pi_y; i++)
  {
    int64_t xi = x / primes[i];
    int64_t bi = pi_bsearch(primes, isqrt(xi));

    for (int64_t j = i; j <= bi; j++)
      sum += pi_bsearch(primes, xi / primes[j]) - (j - 1);
  }

  print("P3", sum, time);
  return sum;
}
Exemple #3
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void eu064(char *ans) {
  int oddcount = 0;

  for (int n = 1; n <= 10000; n++) {
    int a0 = isqrt(n);
    if (a0*a0 == n) continue;
    int a = a0;
    int m = 0;
    int d = 1;
    int i;

    for (i = 0; a != 2 * a0; i++) {
      int m1 = d * a - m;
      int d1 = (n - m1*m1) / d;
      int a1 = (a0 + m1) / d1;

      a = a1;
      m = m1;
      d = d1;
    }

    if (i % 2 == 1) {
      oddcount++;
    }
  }

  sprintf(ans, "%d", oddcount);
}
int64_t S2_hard_mpi(int64_t x,
                    int64_t y,
                    int64_t z,
                    int64_t c,
                    int64_t s2_hard_approx,
                    int threads)
{
  print("");
  print("=== S2_hard_mpi(x, y) ===");
  print("Computation of the hard special leaves");
  print(x, y, c, threads);

  int64_t s2_hard = 0;
  double time = get_time();

  if (is_mpi_master_proc())
    s2_hard = S2_hard_mpi_master(x, y, z, s2_hard_approx);
  else
  {
    FactorTable<uint16_t> factor(y, threads);
    int64_t max_prime = min(y, z / isqrt(y));
    auto primes = generate_primes<int32_t>(max_prime);

    S2_hard_slave((intfast64_t) x, y, z, c, primes, factor, threads);
  }

  print("S2_hard", s2_hard, time);
  return s2_hard;
}
Exemple #5
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void DFT()   //Discrete Fourier Transform  //Äèñêðåòíîå ïðåîáðàçîâàíèå ôóðüå
{            //X(k) = SUMM from n=0 to N-1 (x(n) * exp(-2*pi*i*k*n/N))
    for (K = 1; K<= 15; K++)
    {        //ðàñêëàäûâàåì íà:
        Rex_t = 0;            //Re äåéñòâèòåëüíóþ (cos(x) = sin(x + pi/2)) è
        Imx_t = 0;            //Im ìíèìóþ ÷àñòè (sin(x))

        for (I = 0; I<=31; I++)
        {
            Beta = I * K;
            Beta = Beta & 31;  //Beta < 32
            Tmp_s = Sinus[Beta] * Data[I];      //im = sin(ki)*x(i)  //2pi = 32  =>  2pi/32 = 1
            Tmp_c = Sinus[Beta + 7] * Data[I];  //+pi/2  =  cos
                         
            Tmp_s = Tmp_s >> 8;  //äëÿ íîðìèðîâêè [-255; 255] ý sin(x)
            
            Tmp_c = Tmp_c >> 8;
      
            Rex_t = Rex_t + Tmp_c; //SUMM
            Imx_t = Imx_t - Tmp_s;
       }
                    
       Rex_t = Rex_t >> 3;

       Imx_t = Imx_t >> 3;            

       Tmp_c = Rex_t * Rex_t;      //Re^2
       Tmp_s = Imx_t * Imx_t;      //Im^2

       Tmp_c = Tmp_c + Tmp_s;      //z^2 = Re^2 + Im^2
       Rex[K] = isqrt(Tmp_c);      //z
    }
}
Exemple #6
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//@ ensures \result == 4;
int main () {
  int r;
  r = isqrt(17);
  //@ assert r < 4 ==> \false;
  //@ assert r > 4 ==> \false;
  return r;
}
Exemple #7
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YINLINE YOPTIMIZE_SPEED
int
EnergySobel(unsigned char *inp, int bpp, int pitch,
            int x, int y, int width, int height)
{
  int dx0, dx1, dx2;
  int dy0, dy1, dy2;
  int dx = 0;
  int dy = 0;
  int s2 = 0;

  if (1) {
    dx0 = gradientXCheck(inp, bpp, pitch, x, y, width, height);
    dx1 = gradientXCheck(inp + 1, bpp, pitch, x, y, width, height);
    dx2 = gradientXCheck(inp + 2, bpp, pitch, x, y, width, height);
    dx = (dx0 + 2 * dx1 + dx2) / 4;
    s2 += dx * dx;
  }
  if (1) {
    dy0 = gradientYCheck(inp, bpp, pitch, x, y, width, height);
    dy1 = gradientYCheck(inp + 1, bpp, pitch, x, y, width, height);
    dy2 = gradientYCheck(inp + 2, bpp, pitch, x, y, width, height);
    dy = (dy0 + 2 * dy1 + dy2) / 4;
    s2 += dy * dy;
  }

  return CLIP_TO_8(isqrt(s2));
}
/// @param start      Sieve primes >= start.
/// @param stop       Sieve primes <= stop.
/// @param sieveSize  A sieve size in kilobytes.
/// @pre   start      >= 7
/// @pre   stop       <= 2^64 - 2^32 * 10
/// @pre   sieveSize  >= 1 && <= 2048
///
SieveOfEratosthenes::SieveOfEratosthenes(uint64_t start,
                                         uint64_t stop,
                                         uint_t sieveSize) :
  start_(start),
  stop_(stop),
  sieve_(NULL),
  preSieve_(NULL),
  eratSmall_(NULL),
  eratMedium_(NULL),
  eratBig_(NULL)
{
  if (start_ < 7)
    throw primesieve_error("SieveOfEratosthenes: start must be >= 7");
  if (start_ > stop_)
    throw primesieve_error("SieveOfEratosthenes: start must be <= stop");
  // choose the fastest pre-sieve limit
  limitPreSieve_ = config::PRESIEVE;
  if ((stop_ - start_) < config::PRESIEVE_THRESHOLD)
    limitPreSieve_ = 13;
  sqrtStop_ = static_cast<uint_t>(isqrt(stop_));
  // sieveSize_ must be a power of 2
  sieveSize_ = getInBetween(1u, floorPowerOf2(sieveSize), 2048u);
  sieveSize_ *= 1024; // convert to bytes
  segmentLow_ = start_ - getByteRemainder(start_);
  segmentHigh_ = segmentLow_ + sieveSize_ * NUMBERS_PER_BYTE + 1;
  // allocate the sieve of Eratosthenes array
  sieve_ = new byte_t[sieveSize_];
  init();
}
Exemple #9
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int64_t S2_hard(int64_t x,
                int64_t y,
                int64_t z,
                int64_t c,
                int64_t s2_hard_approx,
                int threads)
{
#ifdef HAVE_MPI
  if (mpi_num_procs() > 1)
    return S2_hard_mpi(x, y, z, c, s2_hard_approx, threads);
#endif

  print("");
  print("=== S2_hard(x, y) ===");
  print("Computation of the hard special leaves");
  print(x, y, c, threads);

  double time = get_wtime();
  FactorTable<uint16_t> factors(y, threads);
  int64_t max_prime = z / isqrt(y);
  vector<int32_t> primes = generate_primes(max_prime);

  int64_t s2_hard = S2_hard_OpenMP_master((intfast64_t) x, y, z, c, (intfast64_t) s2_hard_approx, primes, factors, threads);

  print("S2_hard", s2_hard, time);
  return s2_hard;
}
Exemple #10
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YINLINE YOPTIMIZE_SPEED
int
EnergySobelFast(unsigned char *inp, int bpp, int pitch)
{
  int dx0, dx1, dx2;
  int dy0, dy1, dy2;
  int dx = 0;
  int dy = 0;
  int s2 = 0;

  if (1) {
    dx0 = gradientX(inp, bpp, pitch);
    dx1 = gradientX(inp + 1, bpp, pitch);
    dx2 = gradientX(inp + 2, bpp, pitch);
    dx = (dx0 + 2 * dx1 + dx2) / 4;
    s2 += dx * dx;
  }
  if (1) {
    dy0 = gradientY(inp, bpp, pitch);
    dy1 = gradientY(inp + 1, bpp, pitch);
    dy2 = gradientY(inp + 2, bpp, pitch);
    dy = (dy0 + 2 * dy1 + dy2) / 4;
    s2 += dy * dy;
  }

  return CLIP_TO_8(isqrt(s2));
}
Exemple #11
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int
setblock( void )
{
    if (trans.left < 4)                           /* the real easy part */
    {
        trans.start = trans.next;
        return 0;
    }

    if (trans.left == rows*columns)               /* the fairly easy part */
    {
        trans.count = trans.left;
        trans.left = 0;
        trans.start = trans.next;
        trans.row = rows;
        trans.column = columns;
        return 1;
    }

    /* OK, we got here because there was not enough data to fill the
       rows * columns array.  For the rest of the data in the file
       we have to break it up into smaller parts. The tricky part. */

    trans.row = isqrt((unsigned) trans.left);      /* guaranteed minimum of 4 bytes */
    trans.column = trans.row;
    trans.start = trans.next;
    trans.count = trans.column*trans.row;
    trans.left -= trans.count;
    trans.next += trans.count;
    return 1;
}
Exemple #12
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void Sector::GetCustomSystems(Random& rng)
{
	PROFILE_SCOPED()
	const std::vector<CustomSystem*> &systems = CustomSystem::GetCustomSystemsForSector(sx, sy, sz);
	if (systems.size() == 0) return;

	Uint32 sysIdx = 0;
	for (std::vector<CustomSystem*>::const_iterator it = systems.begin(); it != systems.end(); it++, sysIdx++) {
		const CustomSystem *cs = *it;
		System s(sx, sy, sz, sysIdx);
		s.p = SIZE*cs->pos;
		s.name = cs->name;
		for (s.numStars=0; s.numStars<cs->numStars; s.numStars++) {
			if (cs->primaryType[s.numStars] == 0) break;
			s.starType[s.numStars] = cs->primaryType[s.numStars];
		}
		s.customSys = cs;
		s.seed = cs->seed;
		if (cs->want_rand_explored) {
			/*
			 * 0 - ~500ly from sol: explored
			 * ~500ly - ~700ly (65-90 sectors): gradual
			 * ~700ly+: unexplored
			 */
			int dist = isqrt(1 + sx*sx + sy*sy + sz*sz);
			s.explored = ((dist <= 90) && ( dist <= 65 || rng.Int32(dist) <= 40)) || Faction::IsHomeSystem(SystemPath(sx, sy, sz, sysIdx));
		} else {
			s.explored = cs->explored;
		}
		m_systems.push_back(s);
	}
}
Exemple #13
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  /// Factor numbers <= y
  FactorTable(int64_t y, int threads)
  {
    if (y > max())
      throw primesum_error("y must be <= FactorTable::max()");

    y = std::max<int64_t>(8, y);
    T T_MAX = std::numeric_limits<T>::max();
    factor_.resize(get_index(y) + 1, T_MAX);

    int64_t sqrty = isqrt(y);
    int64_t thread_threshold = ipow(10, 7);
    threads = ideal_num_threads(threads, y, thread_threshold);
    int64_t thread_distance = ceil_div(y, threads);

    #pragma omp parallel for num_threads(threads)
    for (int t = 0; t < threads; t++)
    {
      int64_t low = 1;
      low += thread_distance * t;
      int64_t high = std::min(low + thread_distance, y);
      primesieve::iterator it(get_number(1) - 1);

      while (true)
      {
        int64_t i = 1;
        int64_t prime = it.next_prime();
        int64_t multiple = next_multiple(prime, low, &i);
        int64_t min_m = prime * get_number(1);

        if (min_m > high)
          break;

        for (; multiple <= high; multiple = prime * get_number(i++))
        {
          int64_t mi = get_index(multiple);
          // prime is smallest factor of multiple
          if (factor_[mi] == T_MAX)
            factor_[mi] = (T) prime;
          // the least significant bit indicates
          // whether multiple has an even (0) or odd (1)
          // number of prime factors
          else if (factor_[mi] != 0)
            factor_[mi] ^= 1;
        }

        if (prime <= sqrty)
        {
          int64_t j = 0;
          int64_t square = prime * prime;
          multiple = next_multiple(square, low, &j);

          // moebius(n) = 0
          for (; multiple <= high; multiple = square * get_number(j++))
            factor_[get_index(multiple)] = 0;
        }
      }
    }
  }
void BlockFormation::setStrength(size_t strength_)
{
  strength = strength_;

  n_files = isqrt(strength);
  file_middle = (n_files - 1) * spacing * 0.5f;
  n_ranks = strength / n_files;
  rank_middle = (n_ranks - 1) * spacing * 0.5f;
  incomplete_rank = strength - (n_files * n_ranks);
}
Exemple #15
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void ImgCodeBook::GenerateDistanceTables(void)
{
DualDist	*pDist;
long		i, Count;

	Count = VectList.Count();
	if(Count == 0)
		return;

	SortCodes();

	DistList.Resize(Count);
	pDist = DistList.Addr(0);
	for(i=0; i<Count; i++)
	{
		pDist[i].Origin = isqrt(VectList[i].Mag());
		pDist[i].AntiOrigin = isqrt(VectList[i].InvMag());
	}
}
static int math_sqrt (lua_State *L) {
#ifdef LUA_NUMBER_INTEGRAL
  lua_Number x = luaL_checknumber(L, 1);
  luaL_argcheck(L, 0<=x, 1, "negative");
  lua_pushnumber(L, isqrt(x));
#else
  lua_pushnumber(L, sqrt(luaL_checknumber(L, 1)));
#endif
  return 1;
}
Exemple #17
0
  static uint128 sigma1_sum(const uint64 n) {
    uint32 v = isqrt(n);
    uint128 ret = 0;

    for (uint32 i = 1; i <= v; ++i) {
      uint64 t = n / i;
      ret += uint128(t) * (uint64(2) * i + t + 1);
    }
    ret -= uint128(v) * v * (v + 1);
    return ret >> 1;
  }
Exemple #18
0
/* Sort resulting SRV records */
void sortSrvRecords(kms_server_dns_ptr* serverlist, const int answers)
{
	int i;

	for (i = 0; i < answers; i++)
	{
		serverlist[i]->random_weight = (rand32() % 256) * isqrt(serverlist[i]->weight * 1000);
	}

	qsort(serverlist, answers, sizeof(kms_server_dns_ptr), kmsServerListCompareFunc1);
}
uint64_t PrimeSieve::nthPrime(int64_t n, uint64_t start)
{
  setStart(start);
  double t1 = getWallTime();

  if (n == 0)
    n = 1; // Like Mathematica
  else if (n > 0)
    start = add_overflow_safe(start, 1);
  else if (n < 0)
    start = sub_underflow_safe(start, 1);

  uint64_t stop = start;
  uint64_t dist = nthPrimeDist(n, 0, start);
  uint64_t nthPrimeGuess = add_overflow_safe(start, dist);

  int64_t count = 0;
  int64_t tinyN = 10000;
  tinyN = max(tinyN, pix(isqrt(nthPrimeGuess)));

  while ((n - count) > tinyN ||
         sieveBackwards(n, count, stop))
  {
    if (count < n)
    {
      checkLimit(start);
      dist = nthPrimeDist(n, count, start);
      stop = add_overflow_safe(start, dist);
      count += countPrimes(start, stop);
      start = add_overflow_safe(stop, 1);
    }
    if (sieveBackwards(n, count, stop))
    {
      checkLowerLimit(stop);
      dist = nthPrimeDist(n, count, stop);
      start = sub_underflow_safe(start, dist);
      count -= countPrimes(start, stop);
      stop = sub_underflow_safe(start, 1);
    }
  }

  if (n < 0)
    count -= 1;

  checkLimit(start);
  uint64_t overValue = 3;
  dist = nthPrimeDist(n, count, start) * overValue;
  stop = add_overflow_safe(start, dist);
  NthPrime np;
  np.findNthPrime(n - count, start, stop);
  seconds_ = getWallTime() - t1;

  return np.getNthPrime();
}
Exemple #20
0
int128_t S2_hard(int128_t x,
                 int64_t y,
                 int64_t z,
                 int64_t c,
                 int128_t s2_hard_approx,
                 int threads)
{
#ifdef HAVE_MPI
  if (mpi_num_procs() > 1)
    return S2_hard_mpi(x, y, z, c, s2_hard_approx, threads);
#endif

  print("");
  print("=== S2_hard(x, y) ===");
  print("Computation of the hard special leaves");
  print(x, y, c, threads);

  double time = get_time();
  int128_t s2_hard;

  // uses less memory
  if (y <= FactorTable<uint16_t>::max())
  {
    FactorTable<uint16_t> factor(y, threads);
    int64_t max_prime = min(y, z / isqrt(y));
    auto primes = generate_primes<uint32_t>(max_prime);

    s2_hard = S2_hard_OpenMP((intfast128_t) x, y, z, c, (intfast128_t) s2_hard_approx, primes, factor, threads);
  }
  else
  {
    FactorTable<uint32_t> factor(y, threads);
    int64_t max_prime = min(y, z / isqrt(y));
    auto primes = generate_primes<int64_t>(max_prime);

    s2_hard = S2_hard_OpenMP((intfast128_t) x, y, z, c, (intfast128_t) s2_hard_approx, primes, factor, threads);
  }

  print("S2_hard", s2_hard, time);
  return s2_hard;
}
Exemple #21
0
/*{{{  m_fcircleto*/
void m_fcircleto(int bitmap, int cx, int cy, int rx, int ry)
{
  int x,y,asp,ry2=ry*ry;

  asp=(rx*100)/ry;
  for (y=0; y<=ry; y++)
  {
    x=(isqrt(ry2-y*y)*asp)/100;
    m_lineto(bitmap,cx-x,cy+y,cx+x,cy+y);
    m_lineto(bitmap,cx-x,cy-y,cx+x,cy-y);
  }
}
Exemple #22
0
static uint32_t calc_SSE_H(int16_t *DCT_A, int16_t *DCT_B, uint8_t *IMG_A, uint8_t *IMG_B, int stride)
{
	DECLARE_ALIGNED_MATRIX(sums, 1, 8, uint16_t, CACHE_LINE);
	DECLARE_ALIGNED_MATRIX(squares, 1, 8, uint32_t, CACHE_LINE);
	uint32_t i, Global_A, Global_B, Sum_A = 0, Sum_B = 0;
	uint32_t local[8], MASK_A, MASK_B, Mult1 = 64, Mult2 = 64;

	/* Step 1: Calculate CSF weighted energy of DCT coefficients */
	
	Sum_A = coeff8_energy(DCT_A);
	Sum_B = coeff8_energy(DCT_B);

	/* Step 2: Determine local variances compared to entire block variance */
	
	Global_A = blocksum8(IMG_A, stride, sums, squares);
	Global_B = blocksum8(IMG_B, stride, &sums[4], &squares[4]);

	for (i = 0; i < 8; i++)
		local[i] = (squares[i]<<4) - (sums[i]*sums[i]); /* 16*Var(Di) */

	squares[0] += (squares[1] + squares[2] + squares[3]);
	squares[4] += (squares[5] + squares[6] + squares[7]);

	Global_A = (squares[0]<<6) - Global_A*Global_A; /* 64*Var(D) */
	Global_B = (squares[4]<<6) - Global_B*Global_B; /* 64*Var(D) */

	/* Step 3: Calculate contrast masking threshold */
	
	if (Global_A) 
		Mult1 = ((local[0]+local[1]+local[2]+local[3])<<8) / Global_A;

	if (Global_B)
		Mult2 = ((local[4]+local[5]+local[6]+local[7])<<8) / Global_B;

	MASK_A = isqrt(2*Sum_A*Mult1) + 16;
	MASK_B = isqrt(2*Sum_B*Mult2) + 16;

	if (MASK_B > MASK_A)  /* MAX(MASK_A, MASK_B) */
		MASK_A = ((MASK_B + 32) >> 6);
	else
Exemple #23
0
void test (unsigned x)
{
    unsigned y = isqrt (x);

    printf ("sqrt (%10u) = %10u    %10u <= %10u < %10llu\n",
        x, y, y * y, x, (unsigned long long) (y + 1) * (y + 1));

    if ((unsigned long long) y * y > x)
        printf ("Error! y * y > x\n");

    if (x >= (unsigned long long) (y + 1) * (y + 1))
        printf ("Error! x >= (y + 1) * (y + 1)\n");
}
Exemple #24
0
int perfect(long long a, long long *s)
{
    long long r;

    if (a < 0)
        return 0;

    r = isqrt(a);
    if ((r * r) != a)
        return 0;

    (*s) = r;
    return 1;
}
Exemple #25
0
bool SectorCustomSystemsGenerator::Apply(Random& rng, RefCountedPtr<Galaxy> galaxy, RefCountedPtr<Sector> sector, GalaxyGenerator::SectorConfig* config)
{
	PROFILE_SCOPED()

	const int sx = sector->sx;
	const int sy = sector->sy;
	const int sz = sector->sz;

	if ((sx >= -m_customOnlyRadius) && (sx <= m_customOnlyRadius-1) &&
		(sy >= -m_customOnlyRadius) && (sy <= m_customOnlyRadius-1) &&
		(sz >= -m_customOnlyRadius) && (sz <= m_customOnlyRadius-1))
		config->isCustomOnly = true;

	const std::vector<const CustomSystem*> &systems = galaxy->GetCustomSystems()->GetCustomSystemsForSector(sx, sy, sz);
	if (systems.size() == 0) return true;

	Uint32 sysIdx = 0;
	for (std::vector<const CustomSystem*>::const_iterator it = systems.begin(); it != systems.end(); ++it, ++sysIdx) {
		const CustomSystem *cs = *it;
		Sector::System s(sector.Get(), sx, sy, sz, sysIdx);
		s.m_pos = Sector::SIZE*cs->pos;
		s.m_name = cs->name;
		for (s.m_numStars=0; s.m_numStars<cs->numStars; s.m_numStars++) {
			if (cs->primaryType[s.m_numStars] == 0) break;
			s.m_starType[s.m_numStars] = cs->primaryType[s.m_numStars];
		}
		s.m_customSys = cs;
		s.m_seed = cs->seed;
		if (cs->want_rand_explored) {
			/*
			 * 0 - ~500ly from sol: explored
			 * ~500ly - ~700ly (65-90 sectors): gradual
			 * ~700ly+: unexplored
			 */
			int dist = isqrt(1 + sx*sx + sy*sy + sz*sz);
			if (((dist <= 90) && ( dist <= 65 || rng.Int32(dist) <= 40)) || galaxy->GetFactions()->IsHomeSystem(SystemPath(sx, sy, sz, sysIdx)))
				s.m_explored = StarSystem::eEXPLORED_AT_START;
			else
				s.m_explored = StarSystem::eUNEXPLORED;
		} else {
			if (cs->explored)
				s.m_explored = StarSystem::eEXPLORED_AT_START;
			else
				s.m_explored = StarSystem::eUNEXPLORED;
		}
		sector->m_systems.push_back(s);
	}
	return true;
}
Exemple #26
0
/// Partial sieve function (a.k.a. Legendre-sum).
/// phi(x, a) counts the numbers <= x that are not divisible
/// by any of the first a primes.
///
int64_t phi(int64_t x, int64_t a, int threads)
{
  if (x < 1) return 0;
  if (a > x) return 1;
  if (a < 1) return x;

  print("");
  print("=== phi(x, a) ===");
  print("Count the numbers <= x coprime to the first a primes");

  double time = get_wtime();
  int64_t sum = 0;

  if (is_phi_tiny(a))
    sum = phi_tiny(x, a);
  else
  {
    vector<int32_t> primes = generate_n_primes(a);

    if (primes.at(a) >= x)
      sum = 1;
    else
    {
      // use a large pi(x) lookup table for speed
      int64_t sqrtx = isqrt(x);
      PiTable pi(max(sqrtx, primes[a]));
      PhiCache cache(primes, pi);

      int64_t pi_sqrtx = min(pi[sqrtx], a); 
      sum = x - a + pi_sqrtx;

      int64_t p14 = ipow((int64_t) 10, 14);
      int64_t thread_threshold = p14 / primes[a];
      threads = ideal_num_threads(threads, x, thread_threshold);

      // this loop scales only up to about 8 CPU cores
      threads = min(8, threads);

      #pragma omp parallel for schedule(dynamic, 16) \
          num_threads(threads) firstprivate(cache) reduction(+: sum)
      for (int64_t a2 = 0; a2 < pi_sqrtx; a2++)
        sum += cache.phi<-1>(x / primes[a2 + 1], a2);
    }
  }

  print("phi", sum, time);
  return sum;
}
Exemple #27
0
/* false means donÕt fire this (itÕs in a floor or ceiling or outside of the map), otherwise
	the monster that was intersected first (or NONE) is returned in target_index */
bool preflight_projectile(
	world_point3d *origin,
	short origin_polygon_index,
	world_point3d *destination,
	angle delta_theta,
	short type,
	short owner,
	short owner_type,
	short *obstruction_index)
{
	bool legal_projectile= false;
	struct projectile_definition *definition= get_projectile_definition(type);
	
	(void) (delta_theta);
	
	/* will be used when we truly preflight projectiles */
	(void) (owner_type);
	
	if (origin_polygon_index!=NONE)
	{
		world_distance dx= destination->x-origin->x, dy= destination->y-origin->y;
		angle elevation= arctangent(isqrt(dx*dx + dy*dy), destination->z-origin->z);
		
		if (elevation<MAXIMUM_PROJECTILE_ELEVATION || elevation>FULL_CIRCLE-MAXIMUM_PROJECTILE_ELEVATION)
		{
			struct polygon_data *origin_polygon= get_polygon_data(origin_polygon_index);
			
			// LP note: "penetrates media boundary" means "hit media surface and continue";
			// it will act like "penetrates_media" here
			// Added idiot-proofing to media data
			media_data *media = get_media_data(origin_polygon->media_index);
			if (origin->z>origin_polygon->floor_height && origin->z<origin_polygon->ceiling_height &&
				(origin_polygon->media_index==NONE || definition->flags&(_penetrates_media) || (media ? origin->z>media->height : true)))
			{
				/* make sure it hits something */
				uint16 flags= translate_projectile(type, origin, origin_polygon_index, destination, (short *) NULL, owner, obstruction_index, 0, true, NONE);
				
				*obstruction_index= (flags&_projectile_hit_monster) ? get_object_data(*obstruction_index)->permutation : NONE;
				legal_projectile= true;
			}
		}
	}
	
	return legal_projectile;
}
Exemple #28
0
/* determine next available prime number */
static int next_prime(const int num)
{
    int nprime, factor, root;

    /* nprime has to be larger than num and odd */
    nprime = num + (num & 1) + 1;
    /* there is always a prime between n and 2n */
    while (nprime < 2*num) {
        /* brute force division test on odd factors up to sqrt(nprime) */
        root = isqrt(nprime)+1;
        for (factor = 3; factor < root; factor +=2) {
            if (nprime % factor == 0) break;
        }
        /* if the loop didn't exit early, we have found a prime */
        if (factor >= root) return nprime;
        nprime += 2;
    }
    return nprime;
}
  static int IsOddPrime( unsigned int x )
  {
    register unsigned int root;
    register unsigned int i;

    root = isqrt(x);
    for( i=2; i<MAXPRIMES-1; i++ )
      {
        if( (x%primes[i]) == 0 )
          return False;
        if( (unsigned int) primes[i] >= root )
          return True;
      }

    for( i=primes[MAXPRIMES-1]; i<=root; i+=2 )
      if( (x%i) == 0 )
        return False;
    return True;
  }
int _tmain(int argc, _TCHAR* argv[])
{
	//input
	unsigned long long maxPrime = 500000000;
	unsigned long long maxSearch = isqrt(maxPrime);

	//creating a bit string the length of maxSearch

	bool * bitString;

	bitString = (bool *)malloc((sizeof(bool)*maxPrime) + 1);

	//initialise bit string to true's

	for(unsigned long long i = 0; i < maxPrime; i++)
		bitString[i] = false;

	//sieve

	//let [1] = 1
	unsigned long long counter;
	unsigned long long j;
	for(counter = 2; counter < maxSearch; counter++) 
		//small optimisation starting from square of number
		for(j = counter * counter; j < maxPrime; j += counter) 
		(bitString[j] ? 0 : bitString[j] = true );

	//once bitString is completed print it to file:

	FILE *file;

if (file = fopen("dataOutput.txt", "w"))
{
	for(unsigned long long i = 2; i < maxPrime; i++)
		if(!bitString[i])
		fprintf(file, "%d\n", i);
} else{
	printf("Output file failed to open");
}

	return 0;
}