random.h

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#ifndef RANDOM_H
#define RANDOM_H
#include <cstdlib>
#include <cassert>
 
namespace ModuleBase
{
 
class Random
{
    public:
    Random();
    ~Random();
 
    static void between0and1( double *v, const int &num )
    {
        assert( v!= NULL);
        assert( num > 1);
        for(int i=0; i<num; i++)
        {
            v[i] = static_cast<double>( std::rand() ) / RAND_MAX; 
        }
    }
 
    static double betweenMinus2and2(void)
    {
        return 2.0*betweenMinus1and1();
    }
 
    static double betweenMinus1and1(void)
    {
        const int a = std::rand() % 2;
        if(a==0) return between0and1();
        else if(a==1) return betweenMinus1and0();
        else throw(std::string(__FILE__)+" line "+std::to_string(__LINE__));    // Peize Lin add to fix warning 2019-05-01
    }
 
    static double between0and1(void)
    {
        return static_cast<double>( std::rand() )/RAND_MAX;
    }
 
    static double betweenMinus1and0(void)
    {
        return -static_cast<double>( std::rand() )/RAND_MAX;
    }
 
};
 
}
 
#endif