Executing gen_dc, gen_directsunlight on multiple processors

radiance-general
1

This is an excellent point Mostapha. I do not think that it will work because rtrace_dc cannot work with an ambient file which (I think) one needs for the "-n" option. But, I would be very happy to stand corrected.

Christoph

···

From: Mostapha Sadeghipour [mailto:[email protected]]
Sent: Thursday, September 01, 2011 3:09 PM
To: Radiance general discussion
Subject: [Radiance-general] Executing gen_dc, gen_directsunlight on multiple processors

Hi,

I wonder if anybody know how I can run DAYSIM commands such as gen_dc and gen_directsunlight on multiple processors.

My understanding is both of them are sort of rtrace command so using -n option shouldn't be impossible.

Thanks,
Mostapha

2

I don't think –n requires an ambient cache. It's wasteful of cycles with a traditional point-in-time rendering to not share the ambient data, but it's not required to take advantage of MP.

Rob Guglielmetti IESNA, LEED AP
Commercial Buildings Research Group
National Renewable Energy Laboratory
1617 Cole Blvd MS:RSF202
Golden, CO 80401
T. 303.275.4319
F. 303.630.2055
E. [email protected]

···

On 9/1/11 2:03 PM, "Reinhart, Christoph" <[email protected]<mailto:[email protected]>> wrote:

This is an excellent point Mostapha. I do not think that it will work because rtrace_dc cannot work with an ambient file which (I think) one needs for the “-n” option. But, I would be very happy to stand corrected.

Christoph

From: Mostapha Sadeghipour [mailto:[email protected]]
Sent: Thursday, September 01, 2011 3:09 PM
To: Radiance general discussion
Subject: [Radiance-general] Executing gen_dc, gen_directsunlight on multiple processors

Hi,

I wonder if anybody know how I can run DAYSIM commands such as gen_dc and gen_directsunlight on multiple processors.

My understanding is both of them are sort of rtrace command so using -n option shouldn't be impossible.

Thanks,
Mostapha

3

Hi Mostapha,

the -n option for multiple-core usage as it is implemented into rtrace
is not working for rtrace_dc. In the (still unofficial) version of
rtrace_dc of daysim 3.1, the -n is supported but unfortunately does not
have any impact on the calculation speed... :frowning: . I've tested that
already. So with the current version it doesn't make sense to use this
option and block the other cores.
Maybe a later version supports this option.

Christoph: An ambient file is not necessary for -n.

By the way, does anybody know, if there is a limit for the -n option in
rtrace?
I tested it on my new 48(!!) core machine, but couldn't use more than 9
cores, the other processes are existent but don't use any cpu-time....

Jan

···

Am 01.09.2011 21:08, schrieb Mostapha Sadeghipour:

Hi,

I wonder if anybody know how I can run DAYSIM commands such as gen_dc
and gen_directsunlight on multiple processors.

My understanding is both of them are sort of rtrace command so using
-n option shouldn't be impossible.

Thanks,
Mostapha

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4

Hi Chris, Rob and Jan,

Hopefully this option will be added in the near future. For know I would
like to share the solution I came up with. To have the result on time I ran
multiple simulations at the same time instead of using multiple CPU's for
one simulation.

It's true that you cannot use multiple CPU's to run DAYSIM commands, but
there is no reason not to run multiple DAYSIM commands on one system as far
as you have enough RAM. So you can divide the sensors and run them at the
same time on one system. This simple trick saved me a huge amount of time.

Have a good weekend,
Mostapha

···

On Thu, Sep 1, 2011 at 2:19 PM, Jan Wienold <[email protected]>wrote:

**
Hi Mostapha,

the -n option for multiple-core usage as it is implemented into rtrace is
not working for rtrace_dc. In the (still unofficial) version of rtrace_dc of
daysim 3.1, the -n is supported but unfortunately does not have any impact
on the calculation speed... :frowning: . I've tested that already. So with the
current version it doesn't make sense to use this option and block the other
cores.
Maybe a later version supports this option.

Christoph: An ambient file is not necessary for -n.

By the way, does anybody know, if there is a limit for the -n option in
rtrace?
I tested it on my new 48(!!) core machine, but couldn't use more than 9
cores, the other processes are existent but don't use any cpu-time....

Jan

Am 01.09.2011 21:08, schrieb Mostapha Sadeghipour:

Hi,

I wonder if anybody know how I can run DAYSIM commands such as gen_dc and
gen_directsunlight on multiple processors.

My understanding is both of them are sort of rtrace command so using -n
option shouldn't be impossible.

Thanks,
Mostapha

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