亂數函數 (random-number function)

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亂數函數 (Random-Number Function). Rung-Shiang Cheng Department of Computer and Communication, Kun Shan University [email protected]. Outline. 介紹亂數函數的使用方法 相關範例. 產生亂數 和 模擬生活中的隨機資料. 何時會用到亂數函數呢 ? 統計實驗 … 網路模擬 … ANSI C . 產生 10 個亂數,同時印出 RAND_MAX 的值 (1/2). Example. 把時間當成亂數的種子. - PowerPoint PPT Presentation

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  • (Random-Number Function)Rung-Shiang ChengDepartment of Computer and Communication, Kun Shan [email protected]

  • Outline

  • ? ANSI C

  • 10RAND_MAX(1/2)Example

  • 10RAND_MAX (2/2)

  • ("0")

    1. 2. n

  • 1016Example: .

  • 1016

  • 0 ~ 1Example

  • 0 ~ 1

  • m nExample: m + (rand() % (n m + 1) )

  • m n

  • mn

  • mn

  • m nm + (rand() / RAND_MAX) (n m)

  • m nCase 1: random (20, 60)

  • m nCase 2: random (0, 1)

  • NS-2NS-2?Network Simulator, version 2C++, OTCLRouter, Link, End point, TCP/IP protocolsEthernet, WiFi, Sensor Networks

  • (seed) (distribution) E.g. ParetoConstantUniformExponentialHyperExponentail

    *

  • Uniform Distribution : min_: max_

    *

    NS-22(0 )

  • FTP

  • Error Model (Uniform Distribution)(1/2)TCL Scriptnode0node1( SimpleLink object)error rate : Specify error rateunit : Specify the unit of error (time, pkt, bits)Default: packetranvar : Specify the random variable for generating errors

  • Error Model (Uniform Distribution)(1/2)goodput

  • Error rate (1/2)AWK(sent_drop.awk)

  • Error rate (1/2)&: 5

  • ? (Report)http://teachers.ksu.edu.tw/rscheng/illus/report.htm