On Mon, Jan 5, 2015 at 1:58 PM, Nathaniel Smith <n...@pobox.com> wrote:
> I'm afraid that I really don't understand what you're trying to say. Is > there something that you think numpy should be doing differently? > I liked it better when this raised an exception, instead of creating a rectangular object array. Josef > > On Mon, Jan 5, 2015 at 6:40 PM, Colin J. Williams <cjwilliam...@gmail.com> > wrote: > >> One of the essential characteristics of a matrix is that it be >> rectangular. >> >> This is neither spelt out or checked currently. >> >> The Doc description refers to a class: >> >> - *class *numpy.matrix[source] >> >> <http://github.com/numpy/numpy/blob/v1.9.1/numpy/matrixlib/defmatrix.py#L206> >> >> Returns a matrix from an array-like object, or from a string of data. A >> matrix is a specialized 2-D array that retains its 2-D >> nature through operations. It has certain special operators, such as * >> (matrix multiplication) and ** (matrix power). >> >> This illustrates a failure, which is reported later in the calculation: >> >> A2= np.matrix([[1, 2, -2], [-3, -1, 4], [4, 2 -6]]) >> >> Here 2 - 6 is treated as an expression. >> >> Wikipedia offers: >> >> In mathematics <http://en.wikipedia.org/wiki/Mathematics>, a *matrix* >> (plural *matrices*) is a rectangular >> <http://en.wikipedia.org/wiki/Rectangle> *array >> <http://en.wiktionary.org/wiki/array>*[1] >> <http://en.wikipedia.org/wiki/Matrix_%28mathematics%29#cite_note-1> of >> numbers <http://en.wikipedia.org/wiki/Number>, symbols >> <http://en.wikipedia.org/wiki/Symbol_%28formal%29>, or expressions >> <http://en.wikipedia.org/wiki/Expression_%28mathematics%29>, arranged in >> *rows >> <http://en.wiktionary.org/wiki/row>* and *columns >> <http://en.wiktionary.org/wiki/column>*.[2] >> <http://en.wikipedia.org/wiki/Matrix_%28mathematics%29#cite_note-2>[3] >> <http://en.wikipedia.org/wiki/Matrix_%28mathematics%29#cite_note-3> The >> individual items in a matrix are called its *elements* or *entries*. An >> example of a matrix with 2 rows and 3 columns is >> [image: \begin{bmatrix}1 & 9 & -13 \\20 & 5 & -6 \end{bmatrix}.]In the >> Numpy context, the symbols or expressions need to be evaluable. >> >> Colin W. >> >> >> >> >> >> _______________________________________________ >> NumPy-Discussion mailing list >> NumPy-Discussion@scipy.org >> http://mail.scipy.org/mailman/listinfo/numpy-discussion >> >> > > > -- > Nathaniel J. Smith > Postdoctoral researcher - Informatics - University of Edinburgh > http://vorpus.org > > _______________________________________________ > NumPy-Discussion mailing list > NumPy-Discussion@scipy.org > http://mail.scipy.org/mailman/listinfo/numpy-discussion > >
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