On Sat, Jun 6, 2009 at 12:34 PM, Olivier Verdier <zelb...@gmail.com> wrote:
> I took that very seriously when you said that matrices were important to > you. Far from me the idea of forbidding numpy users to use matrices. > My point was the fact that newcomers are confused by the presence of both > matrices and arrays. I think that there should be only one > matrix/vector/tensor object in numpy. Therefore I would advocate the removal > of matrices from numpy. > > *But* why not have matrices in a different component? Maybe as a part of > scipy? or somewhere else? You would be more than welcome to use them > anywhere. Note that I use components outside numpy for my teaching (scipy, > sympy, mayavi, nosetest) and I don't have any problems with that. > > With my "argument" I endeavoured to explain the potential complications of > using matrices instead of arrays when teaching. Perhaps the strongest > argument against matrices is that you cannot use vectors. I've taught enough > matlab courses to realise the pain that this represents for students. But I > realise also that somebody else would have a different experience. > > Of course x.T*y should be a 1x1 matrix, this is not an anomaly, but it is > confusing for students, because they expect a scalar. That is why I prefer > to teach with dot. Then the relation matrix/vector/scalar is crystal clear. > How about the common expression exp((v.t*A*v)/2) do you expect a matrix exponential here? Or should the students write exp(<v, A*v>/2) where <...> is the inner product? Chuck
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