/* C# Version Copyright (C) 2001 Akihilo Kramot (Takel).       */
/* C# porting from a C-program for MT19937, originaly coded by */
/* Takuji Nishimura, considering the suggestions by            */
/* Topher Cooper and Marc Rieffel in July-Aug. 1997.           */
/* This library is free software under the Artistic license:   */
/*                                                             */
/* You can find the original C-program at                      */
/*     http://www.math.keio.ac.jp/~matumoto/mt.html            */
/*                                                             */

using System;

public class mt19937
{
    /* Period parameters */
    private const int N = 624;
    private const int M = 397;
    private const uint MATRIX_A   = 0x9908b0df; /* constant vector a */
    private const uint UPPER_MASK = 0x80000000; /* most significant w-r bits */
    private const uint LOWER_MASK = 0x7fffffff; /* least significant r bits */
    
    /* Tempering parameters */
    private const uint TEMPERING_MASK_B = 0x9d2c5680;
    private const uint TEMPERING_MASK_C = 0xefc60000;
    
    private static uint TEMPERING_SHIFT_U (uint y) { return (y >> 11); }
    private static uint TEMPERING_SHIFT_S (uint y) { return (y <<  7); }
    private static uint TEMPERING_SHIFT_T (uint y) { return (y << 15); }
    private static uint TEMPERING_SHIFT_L (uint y) { return (y >> 18); }
    
    //static unsigned long mt[N]; /* the array for the state vector  */
    private static uint[] mt = new uint[N];
    
    // static int mti=N+1; /* mti==N+1 means mt[N] is not initialized */
    private static short mti=N+1; /* mti==N+1 means mt[N] is not initialized */
    
    /* initializing the array with a NONZERO seed */
    private static void sgenrand( uint seed)
    {
        /* setting initial seeds to mt[N] using         */
        /* the generator Line 25 of Table 1 in          */
        /* [KNUTH 1981, The Art of Computer Programming */
        /*    Vol. 2 (2nd Ed.), pp102]                  */
        
        mt[0]= seed & 0xffffffffU;
        for (mti=1; mti<N; mti++)
        {
            mt[mti] = (69069 * mt[mti-1]) & 0xffffffffU;
        }
    }
    
    private static uint[/* 2 */] mag01 = {0x0, MATRIX_A};
    /* generating reals */
    /* unsigned long */
    /* for integer generation */
    private static double genrand()
    {
        uint y;
        
        /* mag01[x] = x * MATRIX_A  for x=0,1 */
        if (mti >= N) /* generate N words at one time */
        {
            short kk;
            
            if (mti == N+1) /* if sgenrand() has not been called, */
            {
                sgenrand(4357); /* a default initial seed is used   */
            }
            
            for (kk=0;kk<N-M;kk++)
            {
                y = (mt[kk]&UPPER_MASK)|(mt[kk+1]&LOWER_MASK);
                mt[kk] = mt[kk+M] ^ (y >> 1) ^ mag01[y & 0x1];
            }
            
            for (;kk<N-1;kk++)
            {
                y = (mt[kk]&UPPER_MASK)|(mt[kk+1]&LOWER_MASK);
                mt[kk] = mt[kk+(M-N)] ^ (y >> 1) ^ mag01[y & 0x1];
            }
            
            y = (mt[N-1]&UPPER_MASK)|(mt[0]&LOWER_MASK);
            mt[N-1] = mt[M-1] ^ (y >> 1) ^ mag01[y & 0x1];
            
            mti = 0;
        }
        
        y = mt[mti++];
        y ^= TEMPERING_SHIFT_U(y);
        y ^= TEMPERING_SHIFT_S(y) & TEMPERING_MASK_B;
        y ^= TEMPERING_SHIFT_T(y) & TEMPERING_MASK_C;
        y ^= TEMPERING_SHIFT_L(y);
        
        return ( (double)y / 0xffffffffU ); /* reals */
        /* return y; */ /* for integer generation */
    }

    /* this main() outputs first 1000 generated numbers  */
    public static void Main()
    {
        short j;
        
        sgenrand(4357); /* any nonzero integer can be used as a seed */
        for (j=0; j<1000; j++)
        {
            Console.Write ("{0:f8} ", genrand());
            if (j%8==7)
            {
                Console.Write ("\n");
            }
        }
        Console.Write ("\n");
    }
}