Take the 2-minute tour ×
Computational Science Stack Exchange is a question and answer site for scientists using computers to solve scientific problems. It's 100% free, no registration required.

I could not get accurate description that aids to my understanding of inner blocking size parameter that is used in many LAPACK routines(such as DGEQRT, DLARFB).

Thanks

share|improve this question
    
Could you elaborate a little more? What don't you understand about the inner blocking size parameter? Right now, it seems like you posed a statement, rather than a question. –  Geoff Oxberry Dec 5 '12 at 2:36
    
My question in particular is about, how is inner block size different from Block size? –  zimbra314 Dec 5 '12 at 14:56
add comment

1 Answer

You achieve ideal blocking, if your block fits in your cache. If it does not, it will cost you way more performance. So you have to fit the block size to cache size.

share|improve this answer
    
Can you elaborate a bit more? –  zimbra314 Dec 4 '12 at 14:18
    
Have a look at stackoverflow.com/questions/5200338/… –  vanCompute Dec 4 '12 at 20:08
    
This paper has a short introduction: suif.stanford.edu/papers/lam-asplos91.pdf –  vanCompute Dec 4 '12 at 20:10
    
How is it different from Block size? Why dgemm doesn't use the inner blocking parameter while dgeqrt , dlarfb uses? –  zimbra314 Dec 5 '12 at 18:16
    
This is a very specific question. I am sorry, but I don't have time to dig deeper. I have a link for you: math-atlas.sourceforge.net This is ATLAS a library for automatic tuning, just in case you find that interesting ;-) –  vanCompute Dec 8 '12 at 10:17
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.