# [racket] Matrix Row/Col Ops

First of all I've started using some of the new math and prob stuff "for
real" and it's all fantastic work. Thank you.
Was looking for a routine for sums of a matrix along the either the rows or
cols axis.
See http://docs.scipy.org/doc/numpy/reference/generated/numpy.sum.html
I didn't notice anything but looks straightforward with
matrix-map-rows/cols or similar. As I started one thing I noticed was the
treatment of Matrix Rows and Cols as themselves a Matrix and not as a flat
Array.
>* matrix-row
*- : (All (A) ((Array A) Integer -> (Array A)))
#<procedure:matrix-row>
>* (matrix-row m 0)
*- : (Array Positive-Byte)
(array #[#[1 2]])
In lieu of (array #[#[1 2]]) I would have expected (array #[1 2]). In
other words, a row or column of a matrix is a row or column vector.
in fact currently
>* (matrix-row (matrix-row (matrix-row (matrix-row m 0) 0) 0) 0)
*- : (Array Positive-Byte)
(array #[#[1 2]])
What is the advantage of current approach?
Thanks,
Ray
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