| Re: [eigen] FLENS C++ expression template Library has excellent documentation |
[ Thread Index |
Date Index
| More lists.tuxfamily.org/eigen Archives
]
- To: eigen@xxxxxxxxxxxxxxxxxxx
- Subject: Re: [eigen] FLENS C++ expression template Library has excellent documentation
- From: Gael Guennebaud <gael.guennebaud@xxxxxxxxx>
- Date: Sat, 18 Apr 2009 23:11:29 +0200
- Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:message-id:subject:from:to:content-type :content-transfer-encoding; bh=IiXZzSvTb3C2qpw3gEOAAzYjNgUdDwVS3Hb3SX15nI8=; b=mEJLC8CPeEVFplQeIyH+uCbTA3JJ4eGyhgLuOVbXt+Oj4LK/45bVE48UPAPJhIjFDN Gc3Qo3oZmMTufEVEBDsAXAvELLB/NR1hxjvzKbDV76epjsjo30fVZ5fWJ37eyntKKMCI aFjKZVZLPRJZeCk/dpFhX9IDkESIAZxdukd58=
- Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type:content-transfer-encoding; b=yEtyF3S2C4QQ0nBOHEJxkYzhq1aOg4dj1688P1PJa8DTlb9VgmJVrv62NhhIEFaQEc 9PvACuJQrYopxxPAeOXCi3jzFrAFR2m5DnsnwS8NnPEUkr9ZDu/uHkm+797OMi6NwETd f9fgGdDDxR4kUg79LHWdKHeopv7IkzNJPE3tE=
On Sat, Apr 18, 2009 at 10:33 PM, Ilya Baran <baran37@xxxxxxxxx> wrote:
>> On Sat, Apr 18, 2009 at 6:06 PM, Benoit Jacob <jacob.benoit.1@xxxxxxxxx> wrote:
>>> I really mean to implement Block LLt or partial LU soon, it can be
>>> written cleanly with Eigen blocks.
>>
>> Actually, I've already tried a block LLt implementation (so using BLAS
>> 3 routines) and it was slower than our current level 2 based
>> implementation. so... I wish you good luck as it seems not to be so
>> trivial to get higher performance !
>
> All three variants from FLAME use syrk (A^T * A) which is currently
> half as fast in Eigen as it could be. Could that explain the
> performance penalty or did you use another blocked method?
I think you get a good point. I lost the code, but I remember the
bottleneck was the matrix-matrix product (even when using MKL for this
step). So first step implement a fast syrk....
gael
> -Ilya
>
>
>