dx-packages team mailing list archive

[Ryan Lortie <desrt@xxxxxxxx>]

Public bug reported:

The indicator implements the spec:

  https://wiki.ubuntu.com/Power#Handling_multiple_batteries

which states:

  "Their percentages should be averaged."

Apparently this was taken to mean the simple arithmetic mean, and not
the weighted average (by the capacity of each battery).

  http://bazaar.launchpad.net/~indicator-applet-developers/indicator-
power/trunk.15.04/view/head:/src/service.c#L1316

shows:

  const double percent = sum_percent / n_batteries;

This means that if one battery is twice as large as another, then after
that battery is discharged, 50% would be reported.  I'd expect 33%.

The spec needs to be updated to be less ambiguous about the intended
meaning of the word "average" and the code needs to be fixed.

** Affects: indicator-power (Ubuntu)
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/1430542

Title:
  Indicator doesn't use weighted average with different-sized batteries

Status in indicator-power package in Ubuntu:
  New

Bug description:
  The indicator implements the spec:

    https://wiki.ubuntu.com/Power#Handling_multiple_batteries

  which states:

    "Their percentages should be averaged."

  Apparently this was taken to mean the simple arithmetic mean, and not
  the weighted average (by the capacity of each battery).

    http://bazaar.launchpad.net/~indicator-applet-developers/indicator-
  power/trunk.15.04/view/head:/src/service.c#L1316

  shows:

    const double percent = sum_percent / n_batteries;

  This means that if one battery is twice as large as another, then
  after that battery is discharged, 50% would be reported.  I'd expect
  33%.

  The spec needs to be updated to be less ambiguous about the intended
  meaning of the word "average" and the code needs to be fixed.

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