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Re: Timing graphics in the real world

  • To: mathgroup at smc.vnet.net
  • Subject: [mg123022] Re: Timing graphics in the real world
  • From: Yves Klett <yves.klett at googlemail.com>
  • Date: Mon, 21 Nov 2011 04:25:18 -0500 (EST)
  • Delivered-to: l-mathgroup@mail-archive0.wolfram.com
  • References: <201111191145.GAA18886@smc.vnet.net> <jaaljn$18q$1@smc.vnet.net>

Hi,

why not supply the whole code so we can run some (subjective) timings?

If you have lots of elements, try to use the multi-primitive syntax
(e.g. Polygon[{{a,b,c},{d,e,f},...}]) which can drastically speed up the
rendering.

Regards,
Yves



Am 20.11.2011 11:43, schrieb Ralph Dratman:
> Thank you, Bobby. I understand that. Now how do I speed up the
> graphics? I am prepared to spend $ if necessary! Or... maybe I am
> asking this particular question in the wrong forum. If so... my
> apologies. I don't wish to be a pest.
> 
> Ralph
> 
> On Sat, Nov 19, 2011 at 3:24 PM, DrMajorBob <btreat1 at austin.rr.com> wrote:
>> A quote from Help:
>>
>> "AbsoluteTiming[expr] measures only the time involved in actually evaluating
>> expr, not time involved in formatting the result."
>>
>> Graphics rendering occurs in the FrontEnd, not the Kernel, so AbsoluteTiming
>> doesn't count it.
>>
>> Bobby
>>
>> On Sat, 19 Nov 2011 05:45:59 -0600, Ralph Dratman <ralph.dratman at gmail.com>
>> wrote:
>>
>>> I am trying to find out why a piece of 3D graphics code takes a long
>>> time when scaled up to a lot of little objects. For this purpose I
>>> begin by timing ten runs of a small instance. Here's what my function
>>> calls look like:
>>>
>>> noneOfThat[] :=
>>>  Module[{}, {drawSolidCube[], drawSolidCube[], drawSolidCube[],
>>>   drawSolidCube[], drawSolidCube[], drawSolidCube[], drawSolidCube[],
>>>    drawSolidCube[], drawSolidCube[], drawSolidCube[]}]
>>>
>>> where SolidCube is actually not solid, but rather an aggregate of
>>> about 20 cubelets per image in this first test case.
>>>
>>> AbsoluteTiming[noneOfThat[]]
>>> {0.072105,  ...}
>>>
>>> or if you prefer,
>>>
>>> Timing[noneOfThat[]]
>>> {0.071197,  ...}
>>>
>>> The timing answers are consistent within about 10% across several tries.
>>> Nice.
>>>
>>> Just one problem: here in my universe, on a Core Duo Mac Mini at 2.4
>>> GHz with about 2 GB of free memory, the actual process described above
>>> takes about 10 seconds. The cores stay at around 50% usage (each)
>>> while this is happening. Drawing is taking about 140 times longer than
>>> Mathematica says!
>>>
>>> Next I try the same task with a 2x increase in linear size of the
>>> cube, leading to an 8x increase in volume and number of objects, with
>>> again 10 repetitions in straight-line Mathematica code.
>>>
>>> AbsoluteTiming then says 0.62970 while Timing says 0.574067, both in
>>> the neighborhood of 8 times the earlier figures. Real-world time is
>>> about 85 seconds, also in line with the 8x scaling.
>>>
>>> Again the processors seem to be about half busy, and once again it
>>> takes about 140 times as long to do the real drawing as Mathematica
>>> reports.
>>>
>>> I'm speculating all this means Mathematica is sending my graphics
>>> hardware a bunch of asynchronous drawing calls while simultaneously
>>> announcing, "Done!"
>>>
>>> I infer that a faster graphics card might make a world of difference.
>>> To make that possible, I could switch to a Windows or Linux system if
>>> necessary.
>>>
>>> If possible, I would like the new real-world drawing time to be at
>>> least ten times better than the figures reported here.
>>>
>>> Comments, please? I would be particularly interested to learn about
>>> any specific hardware that might improve the speed.
>>>
>>> Thank you very much.
>>>
>>> Ralph Dratman
>>>
>>
>>
>> --
>> DrMajorBob at yahoo.com
>>
> 



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