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- Working with Triangular Matrices

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bstrouse

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05-21-2012
12:32 PM

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Working with Triangular Matrices

So far, I used the general matrix MKL function dgemv to perform the entire matrix multiplication by the vector while zeroing out the upper triangle of the matrix values so these elements have no effect upon the result vector.

Behind the scenes, what's the difference between using dgemv as I described above and dtrmv to perform this operation? Is dtrmv faster? Without using parallelism which MKL function is the fastest one to use for my operation?

Thanks.

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Chao_Y_Intel

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05-22-2012
08:22 PM

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Hello,

dtrmv will only use upper or lower triangle data, but it does not assume the upper or lower triangle data is 0. For your case, it looks you can zero the upper data, and then use dgemv. But using dtrmv, it may create a different result.

Thanks,

Chao

bstrouse

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05-22-2012
10:03 PM

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Chao_Y_Intel

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05-23-2012
12:28 AM

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Hello,

yes, dtrmv multiplied less elements as it is assuming the symmetric matrix, the dgemv will take the full matrix for multiplication. But have you checkif the result is right for you?

Thanks,

Chao

bstrouse

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05-23-2012
09:24 AM

133 Views

Thanks for the responses.

Blake

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