Computing average of time deltas

Ruby
1

Hello,

Just to make sure I am not reinventing the wheel™ again: is there a
function/lib in Ruby which computes average of timespans? e.g.

first task took 1s:100ms
second task took 1s:400ms
third task took 3s:500ms
--------
average 2s:000ms

TIA,
Peter
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2

On Mar 19, 5:58 am, Peter S. [email protected] wrote:

Just to make sure I am not reinventing the wheel™ again: is there a
function/lib in Ruby which computes average of timespans? e.g.

first task took 1s:100ms
second task took 1s:400ms
third task took 3s:500ms
--------
average 2s:000ms

The Benchmark class lists an example of doing this for a fixed set of
discrete known tasks:

     require 'benchmark'

     n = 50000
     Benchmark.benchmark(" "*7 + CAPTION, 7, FMTSTR, ">total:",

“>avg:”) do |x|
tf = x.report(“for:”) { for i in 1…n; a = “1”; end }
tt = x.report(“times:”) { n.times do ; a = “1”; end }
tu = x.report(“upto:”) { 1.upto(n) do ; a = “1”; end }
[tf+tt+tu, (tf+tt+tu)/3]
end

 The result:

                   user     system      total        real
      for:     1.016667   0.016667   1.033333 (  0.485749)
      times:   1.450000   0.016667   1.466667 (  0.681367)
      upto:    1.533333   0.000000   1.533333 (  0.722166)
      >total:  4.000000   0.033333   4.033333 (  1.889282)
      >avg:    1.333333   0.011111   1.344444 (  0.629761)

It would also be pretty easy to modify the Benchmark.bmbm method to do
this. Just sum and average the results calculated on line 277:
res = Benchmark::measure(&item)

A side note: if you have a never-ending sequence of ‘tasks’ (such as a
task repeated every update frame in a renderer) it is easier to
calculate - and sometimes more desirable - to use a low-pass filter
rather than a running average on a circular- or windowed-list.

For example:
avg_task_time += ( current_task_time - avg_task_time ) / inertia

The higher the ‘inertia’, the less the formula will react to
measurement spikes and the longer it will take to reach a new average.
The closer ‘inertia’ is to zero, the quicker it will react to changes.