// +======================================================================================
// | RANDOM NUMBER GENERATOR 
// +======================================================================================
/*
- initialize: srand(time(NULL));

- integer:  macro randint(MAX+1)
- uniform:  macro randuni()
- gaussian: function randnorm()

*/
#define randint(MAX) (random()%(MAX))
#define randuni() (random()/(RAND_MAX+1.))

double randnorm() {
    
    static int iset = 0;
    static double gset;
    
    double fac, rsq, v1, v2;
    if(iset==0) { 
        do { 
            v1=2.*randuni()-1.;
            v2=2.*randuni()-1.;
            rsq=v1*v1+v2*v2; 
        } while (rsq>=1.||rsq==0.);
            
        fac=sqrt(-2.0*log(rsq)/rsq);gset=v1*fac;iset=1;
        return v2*fac;
    } else { 
        iset = 0;
        return gset;
    } 
}