[Numpy-discussion] untenable matrix behavior in SVN
Tue Apr 29 16:55:38 CDT 2008
Bruce Southey wrote:
> The ability to treat vectors as matrices would be sufficient for my
> needs because these are almost always used in the context of
> vector-matrix multiplication. There is no additional benefit from
> having row or column shapes or metadata because the row/column nature
> is usually predetermined and would be represented by the shape of the
> corresponding matrix.
The benefit is that they can be indexed with a scalar and converted to a
1-d array with r.A, and no reshaping. Also that indexing a matrix
reduces its rank, which is expected in a lot of places.
> It really would be annoying to find that for an
> n by 1 vector/matrix, the product of X.T*X is a scalar or an error
> rather than an n by n matrix.
yes, it would, which is the whole point of the matrix object in the
first place, and the point of the proposed row/column objects. They
would provide 1-d object that behave as row an column vectors with * and **.
Christopher Barker, Ph.D.
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