Class: Metriks::Snapshot

Inherits:
Object
  • Object
show all
Defined in:
lib/metriks/snapshot.rb

Constant Summary collapse

MEDIAN_Q = 
0.5
P75_Q = 
0.75
P95_Q = 
0.95
P98_Q = 
0.98
P99_Q = 
0.99
P999_Q = 
0.999

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(values) ⇒ Snapshot

Returns a new instance of Snapshot.



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# File 'lib/metriks/snapshot.rb', line 12

def initialize(values)
  @values = values.sort
end

Instance Attribute Details

#values ⇒ Object (readonly)

Returns the value of attribute values.



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# File 'lib/metriks/snapshot.rb', line 10

def values
  @values
end

Instance Method Details

#get_75th_percentile ⇒ Object 



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# File 'lib/metriks/snapshot.rb', line 39

def get_75th_percentile
  value(P75_Q)
end

#get_95th_percentile ⇒ Object 



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# File 'lib/metriks/snapshot.rb', line 43

def get_95th_percentile
  value(P95_Q)
end

#get_98th_percentile ⇒ Object 



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# File 'lib/metriks/snapshot.rb', line 47

def get_98th_percentile
  value(P98_Q)
end

#get_999th_percentile ⇒ Object 



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# File 'lib/metriks/snapshot.rb', line 55

def get_999th_percentile
  value(P999_Q)
end

#get_99th_percentile ⇒ Object 



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# File 'lib/metriks/snapshot.rb', line 51

def get_99th_percentile
  value(P99_Q)
end

#median ⇒ Object 



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# File 'lib/metriks/snapshot.rb', line 35

def median
  value(MEDIAN_Q)
end

#size ⇒ Object 



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# File 'lib/metriks/snapshot.rb', line 31

def size
  @values.length
end

#value(quantile) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/metriks/snapshot.rb', line 16

def value(quantile)
  raise ArgumentError, "quantile must be between 0.0 and 1.0" if quantile < 0.0 || quantile > 1.0

  return 0.0 if @values.empty?

  pos = quantile * (@values.length + 1)

  return @values.first if pos < 1
  return @values.last if pos >= @values.length

  lower = @values[pos.to_i - 1]
  upper = @values[pos.to_i]
  lower + (pos - pos.floor) * (upper - lower)
end