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module Stella
# Based on Mongrel::Stats, Copyright (c) 2005 Zed A. Shaw
class Stats
attr_reader :sum, :sumsq, :n, :min, :max
def initialize(name)
@name = name
reset
end
def +(obj)
puts obj.class
end
# Resets the internal counters so you can start sampling again.
def reset
@n, @sum, @sumsq = 0.0, 0.0, 0.0
@last_time = Time.new
@min, @max = 0.0, 0.0
end
# Adds a sampling to the calculations.
def sample(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.to_s}"
end
# Returns a common display (used by dump)
def to_s
"[#{@name}]: SUM=%0.4f, SUMSQ=%0.4f, N=%0.4f, MEAN=%0.4f, SD=%0.4f, MIN=%0.4f, MAX=%0.4f" % [@sum, @sumsq, @n, mean, sd, @min, @max]
end
# Calculates and returns the mean for the data passed so far.
def mean
@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
# Adds a time delta between now and the last time you called this. This
# will give you the average time between two activities.
#
# An example is:
#
# t = Stats.new("do_stuff")
# 10000.times { do_stuff(); t.tick }
# t.dump("time")
#
def tick
now = Time.now
sample(now - @last_time)
@last_time = now
end
end
end
Version data entries
7 entries across 7 versions & 2 rubygems