James, you forgot to add in the following in your time saving
cals:
A= Few seconds * 1 million / 2 = one half millions of a few
seconds
B = A /60 = more time (minutes) for coffee breaks J
Michael Grant, MIT
Engineering | Systemair Inc.
(T) 1-506-743-9500
From: EnergyPlus_Support@xxxxxxxxxxxxxxx
[mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of James V Dirkes
II, PE
Sent: May-19-11 3:56 PM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: RE: [EnergyPlus_Support] Re: Model too big and too complicated?
Part 1 - PC Performances
My opinion:
While CPU and hard disk speed certainly
affect run time and I always like “faster” more than “slower” (in cars and
games as well J), I find
that most of my time for a typical E+ model is spent in developing and testing
the model. For these purposes, I never run an entire weather year until
I’ve tested it thoroughly and am confident that it’s doing everything I
require. These partial year runs, of course, take only a few seconds to a
couple minutes generally. Because I have a million runs (or so) before
I’ve debugged thoroughly and am confident of results, these shorter runs are a
huge time savings .
Once I get to that point, the pressure
is largely relieved and I run a full weather year and do something else (on
another core or another PC) while it’s running. Although the full-year
run takes longer, a) I can do other things and b) there are not that many runs
to wait for in a typical project.
In summary: I think all of the
model definition, setup and testing are 95% and the final runs are 5%. If
my PC was twice as fast I would save 2.5% maximum.
Make sense?
Is your experience different?
The
Building Performance Team
James V. Dirkes II,
P.E., BEMP , LEED AP
1631 Acacia
Drive NW
Grand Rapids, MI 49504
616 450 8653
From:
EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On
Behalf Of Cedric de La Beaujardiere
Sent: Thursday, May 19, 2011 2:12 PM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: [EnergyPlus_Support] Re: Model too big and too complicated?
Part 1 - PC Performances
< /div>
In regards to your 3rd and 4th questions:
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx,
"jipp06" <jippnojunk@...> wrote:
> AND WHAT ABOUT YOU?
> #3 - What kind of PCs are you running. I consider upgrading. I have an
Intel Core2 Duo CPU 2,2 GHz with 2Go RAM running on WIN Vista Ultimate.
>
> #4 - Should I go for more CPUs or more RAM or Both... I understand from
the old msgs on this forum that E+ is single core but there are plans to make
it multi-core, right? I should upgrade to 4CPU's then. I think I'll go for a
Intel Core i7-2600 Processor (3.40GHz, 1066MHz, 8MB) with 4Gb RAM
I work for SolarCity.com and we had just over 600 customers last year for the
residential Energy Efficiency services. For each customer we do about 20 di
fferent simulation runs to model the effects of changing out various components
(like upgrading an old furnace, water heater, etc). Our server has 48
processors of 1.7 GHz and 32 GB RAM. Even with all of that, our single-threaded
simulations take a few minutes (we run the 20 tests in parallel). I wonder how
it would do on a smaller computer...
In general, I would go with both more CPUs and more RAM, not just for E+ but
for other software as well. Your pc is less likely to get stuck if one process
bogs down one of many cores. And most tasks, multiple tasks benefit from more
RAM. A 64-bit system can support more than 4GB of RAM, if the board supports
it.
Cedric
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