classpath.addPath("../figaro_2.11-4.1.0.0.jar")

import com.cra.figaro.language.{Flip, Select}
import com.cra.figaro.library.compound.If
import com.cra.figaro.algorithm.factored.VariableElimination // 变量消除算法

// 定义模型
val sunnyToday = Flip(0.2)
val greetingToday = If(sunnyToday,
                    Select(0.6 -> "Hello, world!", 0.4 -> "Howdy, universe!"),
                    Select(0.2 -> "Hello, world!", 0.8 -> "Oh no, not again"))
val sunnyTomorrow = If(sunnyToday, Flip(0.8), Flip(0.05))
val greetingTomorrow = If(sunnyTomorrow,
                    Select(0.6 -> "Hello, world!", 0.4 -> "Howdy, universe!"),
                    Select(0.2 -> "Hello, world!", 0.8 -> "Oh no, not again"))

// 用推测算法预测今天的问候语
def predict() {
    val result = VariableElimination.probability(greetingToday, "Hello, world!")
    println("Today's greeting is \"Hello, world!\" " +
           "with probability " + result + ".")
}

// 根据今天的问候语是hello world，使用推理算法推理今天的天气
def infer() {
    greetingToday.observe("Hello, world!")
    val result = VariableElimination.probability(sunnyToday, true)
    println("If today's greeting is \"Hello, world!\", today's " +
           "weather is sunny with probability " + result + ".")
}

// 从今天的问候语是hello world这一观测中学习，用推理算法预测明天的问候语
def learnAndPredict() {
    greetingToday.observe("Hello, world!")
    val result = VariableElimination.probability(greetingTomorrow, "Hello, world!")
    println("If today's greeting is \"Hello, world!\", " +
           "tomorrow's greeting will be \"Hello, world!\" " +
           "with probability " + result + ".")
}

// 执行所有任务
predict()
infer()
learnAndPredict()