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- Matrix Q of QR decomposition

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Jorge_Lorente

Beginner

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02-11-2011
12:24 AM

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Matrix Q of QR decomposition

I need to obtain matrix Q of QR decomposition, so I've been using function *geqrf followed by *orgqr and it performs well. The problem is when I use this functions with threaded mkl where i've got good speed up with *geqrf, but no speed up with *orgqr. I've seen user's manual and it seems that *orgqr is not a threaded function; is there any other possibility to obtain the matrix Q with a threaded function??

thanks!!

Jorge

1 Solution

Gennady_F_Intel

Moderator

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02-16-2011
07:06 AM

84 Views

This issue has been submitted to our internal development tracking database for further investigation, we will inform you once a new update becomes available.

Here is a bug tracking number for your reference: **200206100**.

--Gennady

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4 Replies

mecej4

Black Belt

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02-11-2011
04:12 AM

84 Views

Jorge_Lorente

Beginner

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02-11-2011
09:21 AM

84 Views

Thanks!!! :)

Gennady_F_Intel

Moderator

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02-16-2011
07:06 AM

85 Views

This issue has been submitted to our internal development tracking database for further investigation, we will inform you once a new update becomes available.

Here is a bug tracking number for your reference: **200206100**.

--Gennady

Jorge_Lorente

Beginner

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02-17-2011
01:11 AM

84 Views

But I have one more question...I have tested function 'dormqr()' being matrix C an identity matrix and as expected, I have same results as using 'dorgqr()' function. As we can see in the manual, 'dormqr()' is a threaded function, so I've got matrix Q faster than with 'dorgqr()', but for my surprise when I run both functions in sequential MKL 'dormqr()' is near 3 times faster than 'dorgqr()'. How is it posible if both functions make the same and 'dormqr()' also make a matrix-matrix multiplication?

thanks!! :)

Jorge

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For more complete information about compiler optimizations, see our Optimization Notice.