Class: CitizenBudgetModel::Simulator

Inherits:
ActiveRecord::Base
  • Object
show all
Defined in:
app/models/citizen_budget_model/simulator.rb

Instance Method Summary collapse

Instance Method Details

#activate! ⇒ Object

Sets the simulator as active and all others as inactive.



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# File 'app/models/citizen_budget_model/simulator.rb', line 16

def activate!
  self.class.where(active: true).each do |simulator|
    simulator.update!(active: false)
  end
  update!(active: true)
end

#default_equation ⇒ String

Returns a default equation, where the difference between the chosen value and the default value is multiplied by the unit value for each variable.

Returns:

  • (String) —

    a default equation



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# File 'app/models/citizen_budget_model/simulator.rb', line 38

def default_equation
  equation = []
  sections.each do |section|
    section.questions.each do |question|
      equation << question.working_equation
    end
  end
  equation.reject(&:empty?).join(' + ')
end

#solve(variables) ⇒ Float

Solves the equation with the given variables’ values.

Parameters:

  • variables (Hash{Symbol,String=>Float,String}) —

    variables

Returns:

  • (Float) —

    a solution



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# File 'app/models/citizen_budget_model/simulator.rb', line 52

def solve(variables)
  keys = []
  values = []

  variables.each do |key,value|
    keys << key.to_sym
    values << Float(value)
  end

  # Struct will raise a NameError, whereas OpenStruct will not.
  eval(working_equation, Struct.new(*keys).new(*values).instance_eval{binding})
end

#working_equation ⇒ String

Returns the equation or a default equation if not set.

Returns:

  • (String) —

    an equation



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# File 'app/models/citizen_budget_model/simulator.rb', line 26

def working_equation
  if equation?
    equation
  else
    default_equation
  end
end