[Numpy-discussion] array vs matrix

Ondrej Certik ondrej@certik...
Sat Jun 7 14:37:02 CDT 2008


Hi,

what is the current plan with array and matrix with regard of calculating

sin(A)

? I.e. elementwise vs sin(A) = Q*sin(D)*Q^T? Is the current approach
(elementwise for array and Q*sin(D)*Q^T for matrix) the way to go?

We are solving the same problem in SymPy:

http://groups.google.com/group/sympy/browse_thread/thread/6cfe66b012b24948

so I'd like to have the exact same behavior as numpy has, so that we
are compatible. But I was wondering if the current status is ok, or if
many numpy developers (or users?) would like this to be changed.

I think a clean solution is to treat matrices as mathematical objects,
i.e. A*B and sin(A) being matrix multiplication and matrix sin
respectively, while leaving the array for elementwise operations.

But above all, I'd like to be compatible with numpy, otherwise it will
be a mess.

Thanks for any feedback,
Ondrej


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