Re: [eigen] Extending Eigen with AVX |

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*To*: eigen@xxxxxxxxxxxxxxxxxxx*Subject*: Re: [eigen] Extending Eigen with AVX*From*: Rohit Garg <rpg.314@xxxxxxxxx>*Date*: Sun, 3 Mar 2013 23:58:36 -0500*Dkim-signature*: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=x-received:mime-version:in-reply-to:references:from:date:message-id :subject:to:content-type:content-transfer-encoding; bh=+y4gdR1dLjzPmOvdimSYmDqvmKpF4yw1++0nGXOHO8U=; b=DOAQdwmFh7bkckMnTS1tR/y+zeDUYCmqC08pYosDZL/ws+K10UZzVibrbuxHdI8tfa 66i7lr4o9wNTr+J7dTemSs9dqyGteKZHofQsyV+1KDh+ach3RWPUS1UL8KbzZil5hL6N uEpsvb1qWaZ2nz8+OsIJ6biRDkreZGJmvF62rc080tPjTl00H/XBy6QYICrkpp4lz/5h ZdIgB1dfUNIAVlmzArgfdA+sJAqmZzWck65JaFZXX4MUK7NlmP5nkyKQIsgTef4mixa+ IpY3yTomScCLkqxVjTqtj49Xl/muPllVjfq6nxFb1kGBjBNScJ2jkaSnqKuH9Ohv8ckg Ooxg==

On Sun, Mar 3, 2013 at 7:26 AM, Christoph Hertzberg <chtz@xxxxxxxxxxxxxxxxxxxxxxxx> wrote: > On 03.03.2013 01:09, Rohit Garg wrote: >> >> I can work on the PacketMath functions for AVX if there are other >> developers more familiar with Eigen's internals who would be OK with >> helping me integrate this. Sadly, I do not know as much about Eigen's > > > I'm afraid it is not too trivial, mostly because AVX supports packages twice > as large as SSE and there are some parts of Eigen where the packet size is > hard-coded. > There has been the idea of meta-packages some time ago (i.e. put more values > in a package than fit in a register). On the one hand this would help > implementing expressions involving casts (e.g. from float to double) and it > would make AVX-integration "almost trivial". Would it be any easier if we used AVX just for dynamic sized matrices? > > >> internals as I should. Since AVX does not have integer operations, I > > > That's quite a drawback (if packet integer operations are required in an > algorithm) since switching between AVX and SSE is quite costly. That is not neccesarily a problem. If you compile with -mavx on gcc, even the SSE intrinsics use AVX instructions. They get the 3 operand syntax for free. Integer support would become available with AVX2. > > > > Christoph > > > > > -- > ---------------------------------------------- > Dipl.-Inf., Dipl.-Math. Christoph Hertzberg > Cartesium 0.049 > Universität Bremen > Enrique-Schmidt-Straße 5 > 28359 Bremen > > Tel: +49 (421) 218-64252 > ---------------------------------------------- > > -- Rohit Garg http://rpg-314.blogspot.com/ Graduate Student Applied and Engineering Physics Cornell University

**Follow-Ups**:**Re: [eigen] Extending Eigen with AVX***From:*Gael Guennebaud

**References**:**[eigen] Extending Eigen with AVX***From:*Rohit Garg

**Re: [eigen] Extending Eigen with AVX***From:*Christoph Hertzberg

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