Momentary Population Error

Has something gone haywire? Let us know about it!
Post Reply
User avatar
Extrementhusiast
Posts: 1966
Joined: June 16th, 2009, 11:24 pm
Location: USA

Momentary Population Error

Post by Extrementhusiast » April 27th, 2016, 6:03 pm

I just found a bug in which the population count is momentarily, yet obviously, incorrect. Here are some notes to reproduce it:
  • have 17 tabs open in two windows, each with various content, as well as a few other unrelated programs
  • in a simple rule table in which one state is gradually overwritten by another (much like floodfill, but as a rule table)
  • grid size of T3072,3072
  • grid entirely filled with state to be overwritten
  • set single overwriting cell somewhere in the grid
  • while playing at step 2^4, zooming in/out or using arrow keys occasionally results in an incorrect population count (the same number every time, if it's not a question mark), which fixes itself at the next graphical update
    • happens more often if there's random debris (non-interacting cell states) in the way
(This is on an Intel® Core™ i7-5500U CPU @ 2.40GHz running Windows 10, with 8GB of RAM.)
I Like My Heisenburps! (and others)

User avatar
Andrew
Moderator
Posts: 919
Joined: June 2nd, 2009, 2:08 am
Location: Melbourne, Australia
Contact:

Re: Momentary Population Error

Post by Andrew » April 27th, 2016, 7:00 pm

Yep, it is possible for the population count to be temporarily incorrect. I'm pretty sure it can only happen in a hashlife-based algo (all except QuickLife) where calculating the current population can be quite time-consuming. We could avoid the problem by preventing any user interaction while doing that calculation, but that would result in Golly feeling much less responsive.
Use Glu to explore CA rules on non-periodic tilings: DominoLife and HatLife

User avatar
Extrementhusiast
Posts: 1966
Joined: June 16th, 2009, 11:24 pm
Location: USA

Re: Momentary Population Error

Post by Extrementhusiast » April 27th, 2016, 7:46 pm

Andrew wrote:Yep, it is possible for the population count to be temporarily incorrect. I'm pretty sure it can only happen in a hashlife-based algo (all except QuickLife) where calculating the current population can be quite time-consuming. We could avoid the problem by preventing any user interaction while doing that calculation, but that would result in Golly feeling much less responsive.
Eh, probably better the way it currently is, then. I just hadn't seen that behavior before.
I Like My Heisenburps! (and others)

Post Reply