Re: [Boost-users] Max Boost Fusion tuple parameters

Subject: Re: [Boost-users] Max Boost Fusion tuple parameters
From: Rodrigo Madera (rodrigo.madera_at_[hidden])
Date: 2013-09-14 22:39:52

Sorry for not writing back at this thread.

It's been very informative. So thanks!

Larry,
I had this issue for a hypothetical matrix computing problem, but
nothing much practical.

I'm sticking to smaller vectors now.

Best regards,
Rodrigo

On Fri, Jun 14, 2013 at 3:38 PM, Larry Evans <cppljevans_at_[hidden]> wrote:
> On 06/14/13 09:08, Larry Evans wrote:
>> On 06/14/13 04:39, Slava wrote:
>>> On Thu, 13 Jun 2013 14:27:30 +0200, Larry Evans
>>> <cppljevans_at_[hidden]> wrote:
>>>
>>>> It also appears that when TUPLE_SIZE >=100,
>>>> compile time goes up linearly.
>>
>> I think that linear remark was wrong.  It goes up
>> by a factor of about 2 between 100 and 200 and
>> then by another factor of 2 between 200 and 300.
>> That's exponential IIRC :(  Of course I could be
>> misunderstanding again.  It happens :(
>>
>>>
>>>
>>> Take a look at memory usage either, as soon as it starts swapping, it's
>>> far from linear. Your peers will curse you for this code. CDT indexer
>
> Yes.  Looking at the performance monitor as it was compiling
> TUPLE_SiZE=500 showed almost all the memory was used and, IIRC,
> about 40% of swap.
>
>>> (eclipse) takes a lot time and memory on such constructs.
>>> The size of the produced binary (due to debug info for all these small
>>> inlined internal helper functions) must not be forgotten. It's hard to
>>> justify half-Gb executable to the colleagues.
>>>
>>> -- Slava
> [snip]
>
> Using the slim::accumulate template instead of using
> python to generate the summation code doesn't make
> much difference:
>
> tuple_size compile_time
>   10         2.01
>   50         3.37
>  100         6.26
>  200        18.51
>  300        43.79
>  400       109.28
>  500       195.42
>
> Attached is the driver.
>
> I did try to eyeball a fit with qtiplot which showed:
>
>   compile_time = 12*2^(max(0,tuple_size-100)/100)
>
> looked quite similar at tuple_size>=100.
>
> --Larry
>
>
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