Re: [eigen] BLAS backend |

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*To*: eigen@xxxxxxxxxxxxxxxxxxx*Subject*: Re: [eigen] BLAS backend*From*: Benoit Jacob <jacob.benoit.1@xxxxxxxxx>*Date*: Thu, 15 Oct 2009 11:17:59 -0400*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; bh=EbQXDIljTRM/pZyJMpARruJdaQ/laPGK2ThXFW7sS9A=; b=x7KJeH5Q8A7P02CXhm8oh9G7qRLjMKMkczGJzbjhLJd/zODc8dhWMbbi/J3ssn2N1b fIroc/eLjTOW6Lqjb87WCmvAsAcKr3gPiCs5LnkHiPay8wONzKBmVAa+oy6GgvzhgLPn jRNrr5pRizNFP5etxnn+S5/rUTWlQOE5s6zyM=*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; b=p4x/PoiB4IAz4m2Bn5TYiIkgcdf8Br/kzR1k/OuA+YSWTrpMcpdBRaSccGoY3ZjyaE MxR8/kWHR1EWpkq9ddz+vZq8ibJAoOnqLB2Bv7hkpp9sBC3FIUcG5td1doR6luIlMhOE JPaj675IxAvwsfZFrLcuBnEM4lDjA6b2CqnRM=

2009/10/15 Gael Guennebaud <gael.guennebaud@xxxxxxxxx>: > Also note how the matrix copies between the CPU and GPU are extremely > costly... So, now if we agree that a BLAS backend is only worth it to get > GPU support There are other use cases: - parallelized on several cpus/cores - lapack backend can be interesting even on 1 cpu core. > we can think about a smarter approach allowing to keep the data > on the GPU as much as possible, and this in a transparent manner for the > user. Great, if it's transparent to the user, I guess it can be enabled only when appropriate (or in the worst case by asking the user to define a preprocessor symbol). Sounds nice! Benoit > I have a couple of idea about that (and other related stuff) that I'm > going to present next week during an internal GPU workshop to people of my > research center. My hope is that people working on parallel computing will > be interested to build a small collaboration around that. We'll see. > > cheers, > gael. > > > > On Thu, Oct 15, 2009 at 3:22 PM, Benoit Jacob <jacob.benoit.1@xxxxxxxxx> > wrote: >> >> Hello, >> >> This is very interesting and is in our TODO, >> http://eigen.tuxfamily.org/index.php?title=Todo >> >> But work on this hasn't started yet. It shouldn't be hard. For >> example, if you want to use BLAS GEMM, >> you could just plug that in the file >> Eigen/src/Core/products/GeneralMatrixMatrix.h, in the function >> GeneralProduct<Lhs, Rhs, GemmProduct>::scaleAndAddTo(), at line 144 in >> the development branch. Note the little cooking there to get the >> "actual" lhs, rhs, alpha. >> >> Benoit >> >> 2009/10/15 Jean Sreng <jean.sreng@xxxxxx>: >> > Hello, we are currently investigating the use of Eigen2 in our software >> > (VR simulations) and we were wondering about BLAS (and LAPACK) backends. >> > Does the newer (development) version of Eigen provide such backend ? >> > Otherwise, how difficult would it be to implement such backend >> > (partially in a first step, for instance to use BLAS GEMM or >> > tridiagonalisation ?) ? Do you have any thoughts about using this >> > backend with GPU-optimized versions of BLAS (CUBLAS ?) ? >> > >> > Thanks ! >> > >> > -- >> > Jean >> > >> > >> > >> > >> >

**Follow-Ups**:**Re: [eigen] BLAS backend***From:*Gael Guennebaud

**References**:**[eigen] BLAS backend***From:*Jean Sreng

**Re: [eigen] BLAS backend***From:*Benoit Jacob

**Re: [eigen] BLAS backend***From:*Gael Guennebaud

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