scala版本的梅森旋转随机数算法

来源：互联网发布：知进退呼为神编辑：程序博客网时间：2024/05/17 03:53
package xzxzimport scala.annotation.tailrecclass MersenneTwister(seed: Int) {  private val SIZE: Int = 624  private val PERIOD: Int = 397  private val DIFF: Int = SIZE - PERIOD  private def isOdd(n: Int): Int = n & 1  private def m32(n: Int): Int = 0x80000000 & n  private def l31(n: Int): Int = 0x7FFFFFFF & n  private val mersenneTwister = new Array[Int](SIZE)  private var index: Int = 0  resetSeed(seed)  private def generateNumbers(): Unit = {    @tailrec    def rollMersennerTwister(i: Int): Unit = {      if (i < DIFF) {        val y = m32(mersenneTwister(i)) | l31(mersenneTwister(i + 1))        mersenneTwister(i) = mersenneTwister(i + PERIOD) ^ (y >>> 1) ^ (isOdd(y) * 0x9908b0df)        rollMersennerTwister(i + 1)      }    }    rollMersennerTwister(0)    def unroll(i: Int): Unit = {      val y = m32(mersenneTwister(i)) | l31(mersenneTwister(i + 1))      mersenneTwister(i) = mersenneTwister(i - DIFF) ^ (y >>> 1) ^ (isOdd(y) * 0x9908b0df)    }    @tailrec    def startUnroll(i: Int): Unit = {      if (i < SIZE - 1) {        @tailrec        def doUnroll(j: Int): Unit = {          if (j < 11) {            unroll(i)            doUnroll(j + 1)          }        }        startUnroll(i + 1)      }    }    startUnroll(DIFF + 1)    val y = m32(mersenneTwister(SIZE - 1)) | l31(mersenneTwister(SIZE - 1));    mersenneTwister(SIZE - 1) = mersenneTwister(PERIOD - 1) ^ (y >>> 1) ^ (isOdd(y) * 0x9908b0df);  }  final def resetSeed(seed: Int): Unit = {    mersenneTwister(0) = seed    index = 0;    @tailrec    def getmersenneTwister(i: Int): Unit = {      if (i < SIZE) {        mersenneTwister(i) = 0x6c078965 * (mersenneTwister(i - 1) ^ mersenneTwister(i - 1) >>> 30) + i;        getmersenneTwister(i + 1)      }    }    getmersenneTwister(1)  }  /**   * 生成 [0.0, 1.0) 范围内的随机数   */  final def nextFloat(): Double = (nextInt() + 2147483648.0) / 4294967296.0  final def nextInt(): Int = {    if (index == 0)      generateNumbers()    var res: Int = mersenneTwister(index)    res ^= res >>> 11    res ^= res << 7 & 0x9d2c5680    res ^= res << 15 & 0xefc60000    res ^= res >>> 18    index = index + 1    if (index == SIZE)      index = 0    res  }}
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