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- To: eigen@xxxxxxxxxxxxxxxxxxx
- Subject: Re: [eigen] FLENS C++ expression template Library has excellent documentation
- From: Rohit Garg <rpg.314@xxxxxxxxx>
- Date: Sat, 18 Apr 2009 14:02:24 +0530
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Come to think of it, just how many times has the same thing been done
over and over again? A C++ wrapper over something that is of 70's
vintage. FLENS and tn2 are just two examples of that.
On Sat, Apr 18, 2009 at 1:01 PM, Gael Guennebaud
<gael.guennebaud@xxxxxxxxx> wrote:
> On Sat, Apr 18, 2009 at 9:24 AM, Rohit Garg <rpg.314@xxxxxxxxx> wrote:
>>>> I was thinking of something like -DEIGEN_PARALLEL 4 (ie opt in
>>>> parallelization) at compile time to launch that many threads at
>>>> compile time. BLAS 1 should be trivial to parallelize and BLAS2
>>>> shouldn't be too difficult either.
>>>
>>> unfortunately no, the problem is that we need to be able to control
>>> that per expression, and we ave to come up with a good API for
>>> that.Since eigen is a pure template library we cannot have global
>>> states for that.
>>
>> I see. Since the compiler is generating a lot of code for us, we need
>> to parallelize the = assignment operator as it is the one that does
>> all the actual calculations. I don't want to have global state either.
>> May be an eigen_parallel macro which just does omp_set_procs(). So all
>> the functions which are parallel are automatically parallelized w/o
>> user bothering about it. And it can be done per expression. Since
>> changing it per expression is kinda corner case, may be this is a good
>> starting point, at least for discussing what kind of API we want.
>
> yes, we have to study in more details the possibilities offered by
> openMP and how it behaves when nesting parallel loops
>
>>> actually we have already experimented wit openMP, have a look at the
>>> file disabled/EvalOMP.h
>>
>> Curious, why was it disabled?
>
> mainly because of the above API issue
>
>> --
>> Rohit Garg
>>
>> http://rpg-314.blogspot.com/
>>
>> Senior Undergraduate
>> Department of Physics
>> Indian Institute of Technology
>> Bombay
>>
>>
>>
>
>
>
--
Rohit Garg
http://rpg-314.blogspot.com/
Senior Undergraduate
Department of Physics
Indian Institute of Technology
Bombay