Class: Vangrail::RiskScenario

Inherits:
Object
  • Object
show all
Defined in:
lib/vangrail/risk_scenario.rb

Overview

Deployment assumptions changed only by externally adjudicated outcomes.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(prevalence:, threats:) ⇒ RiskScenario

Returns a new instance of RiskScenario.



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# File 'lib/vangrail/risk_scenario.rb', line 121

def initialize(prevalence:, threats:)
  unless prevalence.is_a?(BetaBinomialPrior) && threats.is_a?(DirichletThreatPrior)
    raise ArgumentError, 'scenario needs beta-binomial prevalence and Dirichlet threats'
  end

  @prevalence = prevalence
  @threats = threats
  freeze
end

Instance Attribute Details

#prevalence ⇒ Object (readonly)

Returns the value of attribute prevalence.



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# File 'lib/vangrail/risk_scenario.rb', line 119

def prevalence
  @prevalence
end

#threats ⇒ Object (readonly)

Returns the value of attribute threats.



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# File 'lib/vangrail/risk_scenario.rb', line 119

def threats
  @threats
end

Instance Method Details

#adjudicate(label:, family: nil) ⇒ Object 



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# File 'lib/vangrail/risk_scenario.rb', line 139

def adjudicate(label:, family: nil)
  case label.to_sym
  when :attack
    raise ArgumentError, 'an adjudicated attack needs a threat family' if family.nil?

    self.class.new(prevalence: prevalence.adjudicate(:attack), threats: threats.adjudicate(family))
  when :benign
    raise ArgumentError, 'a benign adjudication cannot name a threat family' unless family.nil?

    self.class.new(prevalence: prevalence.adjudicate(:benign), threats: threats)
  else
    raise ArgumentError, "unknown adjudicated label #{label.inspect}"
  end
end

#prior ⇒ Object 



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# File 'lib/vangrail/risk_scenario.rb', line 131

def prior
  prevalence.mean
end

#threat_mixture ⇒ Object 



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# File 'lib/vangrail/risk_scenario.rb', line 135

def threat_mixture
  threats.mean
end

#to_h ⇒ Object 



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# File 'lib/vangrail/risk_scenario.rb', line 154

def to_h
  { 'prevalence' => prevalence.to_h, 'threats' => threats.to_h }.freeze
end