概率编程——Figaro的HelloWorld示例

概率编程——Figaro的HelloWorld示例

文章目录

• 概率编程——Figaro的HelloWorld示例
• • 0. 导包
  • 1. 定义概率模型
  • 2. 推测方法
  • 3. Main 预测

概率编程——Figaro的HelloWorld示例

0. 导包

a.figaro.algorithm.factored.VariableElimination
a.figaro.language.{Flip, Select}
a.figaro.librarypound.If

1. 定义概率模型

  // 今天天气的概率：晴天0.9，不是晴天0.1val sunnyToday = Flip(0.9)val greetToday = If(sunnyToday,// 如果今天是晴天：说Hello的概率是0.6，说Howdy的概率是0.4Select(0.6 -> "Hello World!", 0.4 -> "Howdy, universe!"),// 如果今天不是晴天：说Hello的概率是0.2，说Howdy的概率是0.8Select(0.2 -> "Hello World!", 0.8 -> "Howdy, universe!"))val sunnyTomorrow = If(sunnyToday,// 如果今天是晴天：明天是晴天的概率是0.8Flip(0.8),// 如果今天是晴天：明天是晴天的概率是0.05Flip(0.05))val greetingTomorrow = If(sunnyTomorrow,// 如果明天是晴天：说Hello的概率是0.6，说Howdy的概率是0.4Select(0.6 -> "Hello World!", 0.4 -> "Howdy, universe!"),// 如果明天是晴天：说Hello的概率是0.2，说Howdy的概率是0.8Select(0.2 -> "Hello World!", 0.8 -> "Howdy, universe!"))

2. 推测方法

• 预测今天的问候语

  def predict(): Unit = {val result = VariableElimination.probability(greetToday, "Hello World!")println(s"Today's greeting is 'Hello World' with probability $result.")}

• 根据今天问候语是Hello World这一事实，推断今天的天气

  def infer(): Unit = {greetToday.observe("Hello World!")val result = VariableElimination.probability(sunnyToday, true)println("If today's greeting is 'Hello World', " +s"today's weather is sunny with probability $result.")}

• 根据今天问候语是Hello World这一事实，预测明天的问候语

  def learnAndPredict(): Unit = {greetToday.observe("Hello World!")val result = VariableElimination.probability(greetingTomorrow, "Hello World!")println("If today's greeting is 'Hello World', " +s"tomorrow's greeting will be 'Hello World' with probability $result.")}

3. Main 预测

  def main(args: Array[String]): Unit = {predict()infer()learnAndPredict()}