gt:         if (max < 1) {
context: /* This Source Code Form is subject to the terms of the Mozilla Public
   * License, v. 2.0. If a copy of the MPL was not distributed with this
   * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
  
  package etomica.util.random;
  
  /*
      A C-program for MT19937, with initialization improved 2002/1/26.
      Coded by Takuji Nishimura and Makoto Matsumoto.
      
      Before using, initialize the state by using init_genrand(seed)  
      or init_by_array(init_key, key_length).
      
      Copyright (C) 1997 - 2002, Makoto Matsumoto and Takuji Nishimura,
      All rights reserved.                          
      
      Redistribution and use in source and binary forms, with or without
      modification, are permitted provided that the following conditions
      are met:
      
        1. Redistributions of source code must retain the above copyright
           notice, this list of conditions and the following disclaimer.
      
        2. Redistributions in binary form must reproduce the above copyright
           notice, this list of conditions and the following disclaimer in the
           documentation and/or other materials provided with the distribution.
      
        3. The names of its contributors may not be used to endorse or promote 
           products derived from this software without specific prior written 
           permission.
      
      THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
      "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
      LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
      A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
      CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
      EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
      PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
      PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
      LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
      NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
      SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
      
      
      Any feedback is very welcome.
      http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html
      email: m-mat @ math.sci.hiroshima-u.ac.jp (remove space)
  */
  
  /**
   * Mersenne Twister RNG.  seed initialization and nextInt() methods written in
   * C by Takuji Nishimura and Makoto Matsumoto as described above, and
   * translated into Java.
   * <p>
   * Other methods added for the Java version.
   *
   * @author Takuji Nishimura
   * @author Makoto Matsumoto
   * @author Andrew Schultz
   */
  public class RandomMersenneTwister implements IRandom {
  
      /* Period parameters */
      static final protected int N = 624;
      static final protected int M = 397;
      static final protected int MATRIX_A = 0x9908b0df;   /* constant vector a */
      static final protected int UPPER_MASK = 0x80000000; /* most significant w-r bits */
      static final protected int LOWER_MASK = 0x7fffffff; /* least significant r bits */
      /* mag01[x] = x * MATRIX_A  for x=0,1 */
      static final int[] mag01 = new int[]{0x0, MATRIX_A};
      protected final int[] mt = new int[N]; /* the array for the state vector  */
      protected int mti = N + 1; /* mti==N+1 means mt[N] is not initialized */
  
      protected boolean hasNextGaussian = false;
      protected double nextGaussian;
      protected int[] savedSeedArray;
      protected int savedSeed;
  
      /**
       * Creates a Mersenne Twister with the given seed.
       */
      public RandomMersenneTwister(int s) {
          setSeed(s);
      }
  
      /**
       * Creates a Mersenne Twister with the given array of seeds.
       */
      public RandomMersenneTwister(int[] s) {
          this(5);
          setSeedArray(s);
      }
  
      public int getSeed() {
          if (savedSeedArray != null) throw new RuntimeException("it's a seed array");
          return savedSeed;
      }
  
      /**
       * Configures the RNG with the given seed.
       */
      public void setSeed(int s) {
          savedSeed = s;
          savedSeedArray = null;
          /* initializes mt[N] with a seed */
          mt[0] = s;
          for (mti = 1; mti < N; mti++) {
              mt[mti] =
                      (1812433253 * (mt[mti - 1] ^ (mt[mti - 1] >>> 30)) + mti);
              /* See Knuth TAOCP Vol2. 3rd Ed. P.106 for multiplier. */
              /* In the previous versions, MSBs of the seed affect   */
              /* only MSBs of the array mt[].                        */
              /* 2002/01/09 modified by Makoto Matsumoto             */
          }
          hasNextGaussian = false;
      }
  
      public int[] getSeedArray() {
          return savedSeedArray;
      }
  
      /**
       * Configures the RNG with an array of seeds
       */
      public void setSeedArray(int init_key[]) {
          /* initialize by an array with array-length */
          /* init_key is the array for initializing keys */
          /* slight change for C++, 2004/2/26 */
          int key_length = init_key.length;
          int i, j, k;
          setSeed(19650218);
          savedSeedArray = init_key.clone();
          i = 1;
          j = 0;
          k = (N > key_length ? N : key_length);
          for (; k > 0; k--) {
              mt[i] = (mt[i] ^ ((mt[i - 1] ^ (mt[i - 1] >>> 30)) * 1664525))
                      + init_key[j] + j; /* non linear */
              i++;
              j++;
              if (i >= N) {
                  mt[0] = mt[N - 1];
                  i = 1;
              }
              if (j >= key_length) j = 0;
          }
          for (k = N - 1; k > 0; k--) {
              mt[i] = (mt[i] ^ ((mt[i - 1] ^ (mt[i - 1] >>> 30)) * 1566083941))
                      - i; /* non linear */
              i++;
              if (i >= N) {
                  mt[0] = mt[N - 1];
                  i = 1;
              }
          }
  
          mt[0] = 0x80000000; /* MSB is 1; assuring non-zero initial array */
      }
  
      /* generates a random number on [0,0xffffffff]-interval */
      public int nextInt() {
          int y;
  
          if (mti >= N) { /* generate N words at one time */
              int kk;
  
              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++];
  
          /* Tempering */
          y ^= (y >>> 11);
          y ^= (y << 7) & 0x9d2c5680;
          y ^= (y << 15) & 0xefc60000;
          y ^= (y >>> 18);
  //        System.out.println("random number "+y);
  
          return y;
      }
  
      public long nextLong() {
          return (((long) nextInt()) << 32) | (nextInt() & ((1L << 32) - 1));
      }
  
      /**
       * Returns a random int ranging from 0 to max-1.
       */
      public int nextInt(int max) {
  