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module Stella
# Based on Mongrel::Stats, Copyright (c) 2005 Zed A. Shaw
class Stats < Array
attr_reader :sum, :sumsq, :n, :min, :max
def initialize
reset
end
def +(obj)
puts obj.class
end
# Resets the internal counters so you can start sampling again.
def reset
self.clear
@n, @sum, @sumsq = 0.0, 0.0, 0.0
@last_time = 0.0
@min, @max = 0.0, 0.0
end
# Adds a sampling to the calculations.
def sample(s)
self << s
update s
end
def update(s)
@sum += s
@sumsq += s * s
if @n == 0
@min = @max = s
else
@min = s if @min > s
@max = s if @max < s
end
@n+=1
end
# Dump this Stats object with an optional additional message.
def dump(msg = "", out=STDERR)
out.puts "#{msg}: #{self.inspect}"
end
# Returns a common display (used by dump)
def inspect
v = [mean, @n, @sum, @sumsq, sd, @min, @max]
t = %q"N=%0.4f SUM=%0.4f SUMSQ=%0.4f SD=%0.4f MIN=%0.4f MAX=%0.4f"
("%0.4f: " << t) % v
end
def to_s; mean.to_s; end
def to_f; mean.to_f; end
def to_i; mean.to_i; end
# Calculates and returns the mean for the data passed so far.
def mean; return 0.0 unless @n > 0; @sum / @n; end
# Calculates the standard deviation of the data so far.
def sd
return 0.0 if @n <= 1
# (sqrt( ((s).sumsq - ( (s).sum * (s).sum / (s).n)) / ((s).n-1) ))
begin
return Math.sqrt( (@sumsq - ( @sum * @sum / @n)) / (@n-1) )
rescue Errno::EDOM
return 0.0
end
end
def recalculate
samples = self.clone
reset
samples.each { |s| sample(s) }
end
end
end
Version data entries
12 entries across 12 versions & 1 rubygems