Commit c64503fb authored by Alexandre Duret-Lutz's avatar Alexandre Duret-Lutz
Browse files

c++11: Simplify random generation code using C++11.

* src/misc/random.cc, src/misc/random.hh (srand, drand, mrand, rrand,
barand): Simplify using <random> from C++11.
(nrand, bmrand, prand): Remove these unused functions.
* src/tgbaalgos/randomgraph.cc: Adjust the use of barand.
* configure.ac: Do not check for srand48 and drand48.
parent 74804707
......@@ -110,7 +110,7 @@ AX_CHECK_BUDDY
AX_CHECK_GSPNLIB
AC_CHECK_HEADERS([sys/times.h])
AC_CHECK_FUNCS([times srand48 drand48 kill alarm])
AC_CHECK_FUNCS([times kill alarm])
LT_CONFIG_LTDL_DIR([ltdl])
LT_INIT([win32-dll])
......
......@@ -21,121 +21,43 @@
// along with this program. If not, see <http://www.gnu.org/licenses/>.
#include "config.h"
#include "_config.h"
#include "random.hh"
#include <cstdlib>
namespace spot
{
std::mt19937 gen;
void
srand(unsigned int seed)
{
#if SPOT_HAVE_SRAND48 && SPOT_HAVE_DRAND48
::srand48(seed);
#else
::srand(seed);
#endif
gen.seed(seed);
}
double
drand()
{
#if SPOT_HAVE_SRAND48 && SPOT_HAVE_DRAND48
return ::drand48();
#else
double r = ::rand();
return r / (1.0 + RAND_MAX);
#endif
return
std::generate_canonical<double,
std::numeric_limits<double>::digits>(gen);
}
int
mrand(int max)
{
return static_cast<int>(max * drand());
std::uniform_int_distribution<> dis(0, max - 1);
return dis(gen);
}
int
rrand(int min, int max)
{
return min + static_cast<int>((max - min + 1) * drand());
}
double
nrand()
{
const double r = drand();
const double lim = 1.e-20;
if (r < lim)
return -1./lim;
if (r > 1.0 - lim)
return 1./lim;
double t;
if (r < 0.5)
t = sqrt(-2.0 * log(r));
else
t = sqrt(-2.0 * log(1.0 - r));
const double p0 = 0.322232431088;
const double p1 = 1.0;
const double p2 = 0.342242088547;
const double p3 = 0.204231210245e-1;
const double p4 = 0.453642210148e-4;
const double q0 = 0.099348462606;
const double q1 = 0.588581570495;
const double q2 = 0.531103462366;
const double q3 = 0.103537752850;
const double q4 = 0.385607006340e-2;
const double p = p0 + t * (p1 + t * (p2 + t * (p3 + t * p4)));
const double q = q0 + t * (q1 + t * (q2 + t * (q3 + t * q4)));
if (r < 0.5)
return (p / q) - t;
else
return t - (p / q);
}
double
bmrand()
{
static double next;
static bool has_next = false;
if (has_next)
{
has_next = false;
return next;
}
double x;
double y;
double r;
do
{
x = 2.0 * drand() - 1.0;
y = 2.0 * drand() - 1.0;
r = x * x + y * y;
}
while (r >= 1.0 || r == 0.0);
r = sqrt(-2 * log(r) / r);
next = y * r;
has_next = true;
return x * r;
std::uniform_int_distribution<> dis(min, max);
return dis(gen);
}
int
prand(double p)
barand::rand()
{
double s = 0.0;
long x = 0;
while (s < p)
{
s -= log(1.0 - drand());
++x;
}
return x - 1;
return (*this)(gen);
}
}
......@@ -24,7 +24,7 @@
# define SPOT_MISC_RANDOM_HH
# include "common.hh"
# include <cmath>
# include <random>
namespace spot
{
......@@ -55,69 +55,18 @@ namespace spot
/// \see mrand, rrand, srand
SPOT_API double drand();
/// \brief Compute a pseudo-random double value
/// following a standard normal distribution. (Odeh & Evans)
///
/// This uses a polynomial approximation of the inverse cumulated
/// density function from Odeh & Evans, Journal of Applied
/// Statistics, 1974, vol 23, pp 96-97.
SPOT_API double nrand();
/// \brief Compute a pseudo-random double value
/// following a standard normal distribution. (Box-Muller)
///
/// This uses the polar form of the Box-Muller transform
/// to generate random values.
SPOT_API double bmrand();
/// \brief Compute pseudo-random integer value between 0
/// and \a n included, following a binomial distribution
/// for probability \a p.
///
/// \a gen must be a random function computing a pseudo-random
/// double value following a standard normal distribution.
/// Use nrand() or bmrand().
///
/// Usually approximating a binomial distribution using a normal
/// distribution and is accurate only if <code>n*p</code> and
/// <code>n*(1-p)</code> are greater than 5.
template<double (*gen)()>
class barand
class SPOT_API barand : protected std::binomial_distribution<>
{
public:
barand(int n, double p)
: n_(n), m_(n * p), s_(sqrt(n * p * (1 - p)))
barand(int n, double p) : binomial_distribution(n, p)
{
}
int
rand() const
{
int res;
for (;;)
{
double x = gen() * s_ + m_;
if (x < 0.0)
continue;
res = static_cast<int> (x);
if (res <= n_)
break;
}
return res;
}
protected:
const int n_;
const double m_;
const double s_;
int rand();
};
/// \brief Return a pseudo-random positive integer value
/// following a Poisson distribution with parameter \a p.
///
/// \pre <code>p > 0</code>
SPOT_API int prand(double p);
/// @}
}
#endif // SPOT_MISC_RANDOM_HH
......@@ -149,7 +149,7 @@ namespace spot
// We want to connect each node to a number of successors between
// 1 and n. If the probability to connect to each successor is d,
// the number of connected successors follows a binomial distribution.
barand<nrand> bin(n - 1, d);
barand bin(n - 1, d);
while (!nodes_to_process.empty())
{
......
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