From: John Perry <john.perry@usm.edu>
Subject: Re: advent of code day 11
Date: Fri, 11 Dec 2020 10:24:01 -0800 (PST) [thread overview]
Message-ID: <b4611f34-d553-4f7c-806a-c799cad8cc0bn@googlegroups.com> (raw)
In-Reply-To: <86mtykp8yd.fsf@stephe-leake.org>
On Friday, December 11, 2020 at 11:08:00 AM UTC-6, Stephen Leake wrote:
> mildly interesting; variation on Conway's Game of Life.
I recognized that, too. A solution should not be hard to parallelize, and I'd like to, but for now I have other tasks. (no pun intended, well, OK yes it was)
Here's a couple of questions for the Ada experts. For each round I used two charts, a source and a result. These are arrays, defined like so:
type Status is ( Floor, Empty, Occupied );
type Chart_Array is array( Positive range <> , Positive range <> ) of Status;
Chart1, Chart2: Chart_Array; -- actually defined with appropriate dimensions
A procedure named `Iterate_Seating` applies the given rules to a Chart_Array; an `if` statement determines which iterates into the other.
I thought it would be clearer to use references to switch from one chart to the other, but I had trouble doing that last night. Now I can get it this way:
Source: Chart_Array renames Chart1;
Result: Chart_Array renames Chart2;
while Changed loop
Perform_Round( Source => Source , Result => Result , ... );
declare Tmp: Chart_Array renames Source;
begin
Source := Result;
Result := Tmp;
end;
end loop;
Does this technique swap references, or does it copy the arrays element-by-element? The run times are the same even if I compel a copy operation; I suppose it's because the arrays aren't large enough, and there aren't enough copies, to make a difference.
thanks
john perry
next prev parent reply other threads:[~2020-12-11 18:24 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-11 17:07 advent of code day 11 Stephen Leake
2020-12-11 18:24 ` John Perry [this message]
2020-12-11 19:07 ` Jeffrey R. Carter
2020-12-11 19:29 ` gautier...@hotmail.com
2020-12-11 19:35 ` gautier...@hotmail.com
2020-12-11 22:40 ` Jeffrey R. Carter
2020-12-11 23:45 ` John Perry
2020-12-11 23:49 ` John Perry
2020-12-12 9:38 ` Maxim Reznik
2020-12-12 20:27 ` Stephen Leake
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