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Fix multiple definition error in random_lcg.h

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This commit is contained in:
Sterling Harper 2017-12-12 17:57:53 -05:00
parent ed5ff626f4
commit ec302b52d6
2 changed files with 30 additions and 20 deletions
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38
src/random_lcg.C
View file

@ -2,16 +2,26 @@
#include <cmath>
// Constants
extern "C" const int N_STREAMS {5};
extern "C" const int STREAM_TRACKING {0};
extern "C" const int STREAM_TALLIES {1};
extern "C" const int STREAM_SOURCE {2};
extern "C" const int STREAM_URR_PTABLE {3};
extern "C" const int STREAM_VOLUME {4};
// Starting seed
int64_t seed = 1;
int64_t seed {1};
// LCG parameters
const uint64_t prn_mult = 2806196910506780709LL; // multiplication factor, g
const uint64_t prn_add = 1; // additive factor, c
const uint64_t prn_mod = 0x8000000000000000; // 2^63
const uint64_t prn_mask = 0x7fffffffffffffff; // 2^63 - 1
const uint64_t prn_stride = 152917LL; // stride between particles
const double prn_norm = pow(2, -63); // 2^-63
constexpr uint64_t prn_mult {2806196910506780709LL}; // multiplication
// factor, g
constexpr uint64_t prn_add {1}; // additive factor, c
constexpr uint64_t prn_mod {0x8000000000000000}; // 2^63
constexpr uint64_t prn_mask {0x7fffffffffffffff}; // 2^63 - 1
constexpr uint64_t prn_stride {152917LL}; // stride between
// particles
constexpr double prn_norm {pow(2, -63)}; // 2^-63
// Current PRNG state
uint64_t prn_seed[N_STREAMS]; // current seed
@ -84,19 +94,19 @@ future_seed(uint64_t n, uint64_t seed)
// and C which can then be used to find x_N = G*x_0 + C mod 2^M.
// Initialize constants
uint64_t g = prn_mult;
uint64_t c = prn_add;
uint64_t g_new = 1;
uint64_t c_new = 0;
uint64_t g {prn_mult};
uint64_t c {prn_add};
uint64_t g_new {1};
uint64_t c_new {0};
while (n > 0) {
// Check if the least significant bit is 1.
if (n & 1) {
g_new = g_new * g;
g_new *= g;
c_new = c_new * g + c;
}
c = (g + 1) * c;
g = g * g;
c *= (g + 1);
g *= g;
// Move bits right, dropping least significant bit.
n >>= 1;

12
src/random_lcg.h
View file

@ -7,12 +7,12 @@
// Module constants.
//==============================================================================
extern "C" const int N_STREAMS = 5;
extern "C" const int STREAM_TRACKING = 0;
extern "C" const int STREAM_TALLIES = 1;
extern "C" const int STREAM_SOURCE = 2;
extern "C" const int STREAM_URR_PTABLE = 3;
extern "C" const int STREAM_VOLUME = 4;
extern "C" const int N_STREAMS;
extern "C" const int STREAM_TRACKING;
extern "C" const int STREAM_TALLIES;
extern "C" const int STREAM_SOURCE;
extern "C" const int STREAM_URR_PTABLE;
extern "C" const int STREAM_VOLUME;
//==============================================================================
// PRN generates a pseudo-random number using a linear congruential generator.