[Radiance-general] starting rpict -S 1 -P pfile

[Gregory J. Ward]

Hi Lars,

You don't need the -P or -PP option to synchronize rpict using -o.   
If you read the man page carefully, you'll see that the coordination  
happens simply because rpict -S skips -o outputs that are already  
started.  This is the same way -PP works, so the two functions are  
orthogonal.

-Greg

P.S.  You could use ranimate for this purpose, but there's no real  
advantage, and you would have to turn frame interpolation off.

> From: "Lars O. Grobe" <grobe at gmx.net>
> Date: October 16, 2005 3:44:58 AM PDT
>
> Hi Greg!
>
>
>> There's no sense in using the -P option if you're after parallel  
>> runs, because -P insists on serial runs -- it's a mechanism to  
>> connect sequential invocations to the same process.  It's exactly  
>> the opposite of what you need.  Just use multiple rpicts if  
>> OpenMosix doesn't support shared memory.  It will be the same as  
>> using -PP in that case, since there's nothing about the -PP option  
>> that *requires* shared memory.  It just ends up using it if it's  
>> available.
>>
>
> Well, the reason why I wanted to use -P is that I need some way to  
> make the processes render just the missing frames. So they need to  
> be synced. If I use just several rpict's without -PP, I will have  
> to split my view files, and that means that I have to regroup the  
> views in the view files each time that the cluster configuration  
> changes.
>
> The problem with using rpict with -PP is that rpict will share  
> memory, and than openmosix will not allow the processes to migrata  
> any more. So if the -PP option is the only way to make multiple  
> rpict processes sync, I will have to go back and use a target for  
> each view in my Makefile. Than I can use make -j # with # being the  
> number of machines, the most generic way to distribute the  
> processes. I am not too happy with that because I will have the  
> problem with the viewfiles sooner or later when starting animations  
> - I cannot have one target per frame, so I will have to find a way  
> to render ONE viewfile's views in parallel without that "shared  
> memory".
>
> In fact I am seriously considering using ranimate for my stills  
> now, as this allows me to distribute processes from ONE viewfile. I  
> could simply add HOST-lines pointing to localhost, which is a bit  
> silly, but should work fine.
>
> Thank you for all the help, and have a nice week-end, we have a  
> nice sunny autumn day here and it is a pity to stay in the lab ;-)
>
> CU Lars.
>