On 10/24/2013 09:30 AM, Dmitry Cherkassov wrote:
Hi.
On Thu, Oct 24, 2013 at 7:16 PM, Tobias Hammer <tobias.ham...@dlr.de> wrote:
matrix-dot is what you want.
Tobias
OK, it indeed works.
Hence, there is an error in docs
http://docs.racket-lang.org/math/matrix_inner.html?q=matrix-dot&q=normalize#%28def._%28%28lib._math%2Fmatrix..rkt%29._matrix-dot%29%29
Specifically, there is said:
In other words the sum of (* a (conjugate b)) is computed where a runs over the
entries in M and b runs over the corresponding entries in N.
and `conjugate' link leads to complex conjugate function, whereas
there should be `transpose' function.
The Frobenius inner product is often defined as the trace of A*B^T,
where "^T" means conjugate transpose for complex matrices. Most of the
entries in A*B^T are thrown away by computing the trace. Computing the
trace ends up equivalent to multiplying A elementwise by B's elementwise
conjugation, so the docs are correct.
I think I can make the `matrix-dot' docs communicate better, though,
especially to people who are looking for vector operations. I'm open to
suggestions to improve them generally.
Neil ⊥
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