|| || || || || || || ||

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Random.h

Go to the documentation of this file.

#ifndef Impala_Util_Random_h
#define Impala_Util_Random_h

#include "Basis/ILog.h"
#include <ctime>
#include <cstdlib>

namespace Impala
{
namespace Util
{

static void
SetRandomSeed(int seed)
{
    std::srand(seed);
}
    
static void
RandomiseSeed()
{
    SetRandomSeed(time(0));
}
    
int
RandomInt(int upperBound)
{
    ILOG_VAR(Impala.Util.Random.RandomInt);
    if(upperBound > RAND_MAX)
        ILOG_WARNING(upperBound <<" upperBound > RAND_MAX "<< RAND_MAX);
    return (int) (((double) std::rand() / ((double) RAND_MAX + 1.0)) *
                  upperBound);
}

int
RandomInt()
{
    return RandomInt(RAND_MAX);
}
    
double
RandomDouble(double upperBound)
{
    ILOG_VAR(Impala.Util.Random.RandomDouble);
    if(upperBound > RAND_MAX)
        ILOG_WARNING(upperBound <<" upperBound > RAND_MAX");
    return (double) (((double) std::rand() / ((double) RAND_MAX + 1.0)) *
                     upperBound);
}

double
RandomDouble()
{
    return RandomDouble(1.);
}

std::set<int>
RandomUniqueNumbers(int count, int upperBound)
{
    ILOG_VAR(Impala.Util.Random.RandomUniqueNumbers);
    std::set<int> set;
    if(count > upperBound)
    {
        ILOG_ERROR("count > upperBound:"<< count <<" "<< upperBound);
        return set;
    }
    if(count > RAND_MAX)
    {
        ILOG_ERROR("count > RAND_MAX:"<< count <<" "<< RAND_MAX);
        return set;
    }
    while(set.size() < count)
    {
        int draw = RandomInt(upperBound);
        if(set.find(draw) == set.end())
            set.insert(draw);
    }
    return set;
}

void
DumpRandomSequence(int seed, int length, int maxint)
{
    std::ofstream ofs("randomdump.txt");
    if(!ofs.is_open())
        return;
    ofs << length <<" random numbers below "<< maxint << ", seed == "<< seed <<"\n";
    Util::SetRandomSeed(seed);
    for(int i=0 ; i<length ; ++i)
        ofs << Util::RandomInt(maxint) << ((i%20==19)?"\n":" ");
}
    
} // namespace Util
} // namespace Impala

#endif

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