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classpath.addPath("../jsci-1.2.jar")
classpath.addPath("../figaro_2.11-4.1.0.0.jar")
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import com.cra.figaro.language._
import com.cra.figaro.library.compound._
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// 打印机模型
val printerPowerButtonOn = Flip(0.95)
val tonerLevel = Select(0.7 -> 'high, 0.2 -> 'low, 0.1 -> 'out)
val tonerLowIndicatorOn =
If(printerPowerButtonOn,
CPD(tonerLevel,
'high -> Flip(0.2),
'low -> Flip(0.6),
'out -> Flip(0.99)),
Constant(false))
val paperFlow = Select(0.6 -> 'smooth, 0.2 -> 'uneven, 0.2 -> 'jammed)
val paperJamIndicatorOn =
If(printerPowerButtonOn,
CPD(paperFlow,
'smooth -> Flip(0.1),
'uneven -> Flip(0.3),
'jammed -> Flip(0.99)),
Constant(false))
val printerState =
Apply(printerPowerButtonOn, tonerLevel, paperFlow,
(power: Boolean, toner: Symbol, paper: Symbol) => {
if(power) {
if(toner == 'high && paper == 'smooth) 'good
else if(toner == 'out || paper == 'jammed) 'out
else 'poor
} else 'out
})
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// 打印机故障模型
val softwareState =
Select(0.8 -> 'correct, 0.15 -> 'glitchy, 0.05 -> 'crashed)
val networkState =
Select(0.7 -> 'up, 0.2 -> 'intermittent, 0.1 -> 'down)
val userCommandCorrect = Flip(0.65)
val numPrintedPages =
RichCPD(userCommandCorrect, networkState,
softwareState, printerState,
(*, *, *, OneOf('out)) -> Constant('zero),
(*, *, OneOf('crashed), *) -> Constant('zero),
(*, OneOf('down), *, *) -> Constant('zero),
(OneOf(false), *, *, *) -> Select(0.3 -> 'zero, 0.6 -> 'some, 0.1 -> 'all),
(OneOf(true), *, *, *) -> Select(0.01 -> 'zero, 0.01 -> 'some, 0.98 -> 'all))
val printsQuickly =
Chain(networkState, softwareState,
(network: Symbol, software: Symbol) =>
if(network == 'down || software == 'crashed)
Constant(false)
else if(network == 'intermittent || software == 'glitchy)
Flip(0.5)
else Flip(0.9))
val goodPrintQuality =
CPD(printerState,
'good -> Flip(0.95),
'poor -> Flip(0.3),
'out -> Constant(false))
val printResultSummary =
Apply(numPrintedPages, printsQuickly, goodPrintQuality,
(pages: Symbol, quickly: Boolean, quality: Boolean) =>
if(pages == 'zero) 'none
else if(pages == 'some || !quickly == !quality) 'poor
else 'excellent)
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import com.cra.figaro.algorithm.factored.VariableElimination
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// 1. 没有数据时，打印机电源按钮开启的先验概率
val answerWithNoEvidence = VariableElimination.probability(printerPowerButtonOn, true)
println("Prior probability the printer power button is on = " + answerWithNoEvidence)
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// 2. 如果打印结果不佳，但是不是用户想要的结果
printResultSummary.observe('poor)
val answerIfPrintResultPoor = VariableElimination.probability(printerPowerButtonOn, true)
println("Probability the printer power button is on given a poor result = " + answerIfPrintResultPoor)
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// 3. 什么都没有打印进行查询
printResultSummary.observe('none)
val answerIfPrintResultNone = VariableElimination.probability(printerPowerButtonOn, true)
println("Probability the printer power button is on given empty result = " + answerIfPrintResultNone)
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// 4. printer power button on --> printer state --> print result summary路径上，如果观测到printer state时被阻塞
// 已知打印机状态为停机，得知打印结果为空并没有改变打印机电源按钮开启的概率。
// 因为在Printer State给定的情况下，Print Result Summary条件独立于Printer Power Button on
printResultSummary.unobserve()
printerState.observe('out)
val answerIfPrinterStateOut = VariableElimination.probability(printerPowerButtonOn, true)
println("Probability the printer power button is on given " + "out printer state = " + answerIfPrinterStateOut)
printResultSummary.observe('none)
val answerIfPrinterStateOutAndResultNone = VariableElimination.probability(printerPowerButtonOn, true)
println("Probability the printer power button is on given out printer state and empty result = " + answerIfPrinterStateOutAndResultNone)
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// 5. 如果观察到墨粉不足指示灯，打印机状态良好的概率下降
printResultSummary.unobserve()
printerState.unobserve()
val printerStateGoodPrior = VariableElimination.probability(printerState, 'good)
println("Prior probability the printer state is good = " + printerStateGoodPrior)
tonerLowIndicatorOn.observe(true)
val printerStateGoodGivenTonerLowIndicatorOn = VariableElimination.probability(printerState, 'good)
println("Probability printer state is good given low toner indicator = " + printerStateGoodGivenTonerLowIndicatorOn)
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// 6. 一般来说网络正常运行和软件状态相对独立
tonerLowIndicatorOn.unobserve()
val softwareStateCorrectPrior = VariableElimination.probability(softwareState, 'correct)
println("Prior probability the software state is correct = " + softwareStateCorrectPrior)
networkState.observe('up)
val softwareStateCorrectGivenNetworkUp = VariableElimination.probability(softwareState, 'correct)
println("Probability software state is correct given network up = " + softwareStateCorrectGivenNetworkUp)
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// 7. 如果打印机速度较慢，而得知网络正常连接，将显著降低软件状态正确的概率
// Software State和Network State是独立的，但是在Prints Quickly给定的情况下，导致了诱导依赖性，使得两者不再条件独立
networkState.unobserve()
printsQuickly.observe(false)
val softwareStateCorrectGivenPrintsSlowly = VariableElimination.probability(softwareState, 'correct)
println("Probability software state is correct given prints slowly = " + softwareStateCorrectGivenPrintsSlowly)
networkState.observe('up)
val softwareStateCorrectGivenPrintsSlowlyAndNetworkUp = VariableElimination.probability(softwareState, 'correct)
println("Probability software state is correct given prints slowly and network up = " + softwareStateCorrectGivenPrintsSlowlyAndNetworkUp)
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