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The mkl_?imatcopy functions require an extra leading dimension parameter, called ldb.

From the documentation, I am not sure what value it should be used for this parameter. As an answer, I would like that the following case be considered:

A = (lda = 7 for row-major)

[x x x x x x x]

[x x a b c x x]

[x x d e f x x]

[x x x x x x x]

Transposed =

[x x x x x x x]

[x x a d b x x]

[x x e c f x x]

[x x x x x x x]

What value for ldb should be used in mkl_?imatcopy?

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You cannot do this with mkl_?imatcopy, because elements b and e are not adjacent in the result - this permutation is not a transposition.

parameter ldb is the output stride. When you transpose M-by-N matrix you mean your input(m,n) is located at input[m*LDA+n] and your output(n,m) is located at output[n*LDB+m]

Thanks

Dima

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Thanks Dmitry. I am in doubt now. Can I use mkl_?imatcopy on a matrix block? If not, I can only think of **lda** being always **cols** (row major order). Also, for a MxN matrix with *lda = N*, what would be ldb? M?

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Thanks Evarist. Is there a scenario where **ldb** is different from **lda**?

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