POV-Ray : Newsgroups : povray.binaries.images : Strange behaviour of mod() Server Time
5 Nov 2024 10:22:13 EST (-0500)
  Strange behaviour of mod() (Message 1 to 4 of 4)  
From: Jörg "Yadgar" Bleimann
Subject: Strange behaviour of mod()
Date: 20 Sep 2024 22:21:27
Message: <66ee2da7$1@news.povray.org>
Hi(gh)!

For generating a time display for my current attempt at a Satisfactory 
1.0 speedrun, I use the following code:

#declare hours=div(clock,90000);
#declare minutes=mod(div(clock,1500),60);
#declare seconds=mod(div(clock,25),60);
#declare centiseconds=mod(clock,25)*4;

and the text object is built like:

concat(str(hours,-2,0),":",str(minutes,-2,0),"'",str(seconds,-2,0),",",str(centiseconds,-2,0)),0.001,0

But whenever the clock value is divisible by 25 without remainder, I get 
"100" instead of "00" for the centiseconds part of the timestamp. Why?

See you in Khyberspace!

Yadgar

-- 
VBI BENE, IBI BACTRIA!


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From: MichaelJF
Subject: Re: Strange behaviour of mod()
Date: 21 Sep 2024 02:33:27
Message: <66ee68b7$1@news.povray.org>
Am 21.09.2024 um 04:21 schrieb Jörg "Yadgar" Bleimann:
> Hi(gh)!
> 
> For generating a time display for my current attempt at a Satisfactory 
> 1.0 speedrun, I use the following code:
> 
> #declare hours=div(clock,90000);
> #declare minutes=mod(div(clock,1500),60);
> #declare seconds=mod(div(clock,25),60);
> #declare centiseconds=mod(clock,25)*4;
> 
> and the text object is built like:
> 
>
concat(str(hours,-2,0),":",str(minutes,-2,0),"'",str(seconds,-2,0),",",str(centiseconds,-2,0)),0.001,0
> 
> But whenever the clock value is divisible by 25 without remainder, I get 
> "100" instead of "00" for the centiseconds part of the timestamp. Why?
> 
> See you in Khyberspace!
> 
> Yadgar
> 
Hi Yadgar,

mod() seems to affect only the integer part of a float value. E.g., 
mod(24.88248825,25)=24.88248825 and mod(25.00250053,25)=0.00250053.

The value of 100 comes from the rounding by str(value,-2,0). E.g.,
str(24.88248825*4,2,0)=str(99.52995300,-2,0)=100, as the fractional part 
is greater than 0.5.

Maybe

#declare centiseconds=floor(mod(clock,25)*4);

will serve you better.

Regards
Michael


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From: Jörg "Yadgar" Bleimann
Subject: Re: Strange behaviour of mod()
Date: 21 Sep 2024 09:42:34
Message: <66eecd4a$1@news.povray.org>
Hi(gh)!

On 21.09.24 08:33, MichaelJF wrote:

> mod() seems to affect only the integer part of a float value. E.g., 
> mod(24.88248825,25)=24.88248825 and mod(25.00250053,25)=0.00250053.
> 
> The value of 100 comes from the rounding by str(value,-2,0). E.g.,
> str(24.88248825*4,2,0)=str(99.52995300,-2,0)=100, as the fractional part 
> is greater than 0.5.
> 
> Maybe
> 
> #declare centiseconds=floor(mod(clock,25)*4);
> 
> will serve you better.

When I tried this, I got centiseconds from 03 to 99... also not 
satisfactory (pun intended!), as I wanted 04 to 00 (or 00 to 96). Then I 
looked up my command line... and noticed that +kf and +kff were not 
identical (+kf154115 but, accidentally, +kff145155)! So there was a tiny 
but growing fractional remainder at each frame number divisible by 25! I 
corrected this, and now it works perfect even without floor()! 
Nevertheless, thank you for your suggestion!

See you in Khyberspace!

Yadgar


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From: Jörg "Yadgar" Bleimann
Subject: Re: Strange behaviour of mod()
Date: 21 Sep 2024 11:21:02
Message: <66eee45e$1@news.povray.org>
Hi(gh)!

On 21.09.24 15:42, Jörg "Yadgar" Bleimann wrote:

> (+kf154115 but, accidentally, +kff145155)!

Whoops, wrong... the erroneous +kff value was 154155, not 145155!

Excuse me, I caught cold and thus my IQ became temporarily two-digit...

See you in Khyberspace!

Yadgar

-- 
VBI BENE, IBI BACTRIA!


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