On Thu, Feb 17, 2011 at 11:34 AM, Ondrej Certik <[email protected]> wrote: > On Thu, Feb 17, 2011 at 8:35 AM, Chris Smith <[email protected]> wrote: >> Ronan Lamy wrote: >>> Le mercredi 16 février 2011 à 22:24 -0800, Ondrej Certik a écrit : >>>> 2) NumPy array() >>>> >>>> So that you can use syntax like: >>>> >>>> xdata = array([1, 2, 3, 4, 5]) >>>> ydata = xdata ** 2 >>>> data2 = array([xdata, 1.5 * ydata]) >>>> >>>> which just works in Mathematica (it's in the core language). >>>> >>> >>> I don't really see the point of having this in sympy. Which actual >>> problems does it solve? >> >> It's just sugar, and I think that's what is meant by "it just works". I'm >> guessing the above means the following in python: >> >> ydata = [xi**2 for xi in xdata] >> data2 = zip(xdata, [yi*1.5 for yi in ydata]) > > Well, this is what it means: > > In [1]: from numpy import array > In [2]: xdata = array([1, 2, 3, 4, 5]) > In [3]: ydata = xdata ** 2 > In [4]: data2 = array([xdata, 1.5 * ydata]) > In [5]: data2 > Out[5]: > array([[ 1. , 2. , 3. , 4. , 5. ], > [ 1.5, 6. , 13.5, 24. , 37.5]]) > > Btw, we already have a similar concept in SymPy: Matrix. But it > represents a math matrix and that's it. I think we need an array > concept as well. > > Ronan --- the actual problem that it solves is that in Mathematica, > people do use the syntactic sugar for arrays. So I would like to use > the same thing in SymPy. Which I can, using numpy, but as I said, > sometimes numpy is not available, and I want this to always work.
Here is a preliminary implementation, so that you can comment on it: https://github.com/certik/sympy/commit/00a77c35dd0d603826aa29fe1c9528e34d08142e as you can see, it's very simple. So far it's only 1D arrays, I still have to implement multidimensional arrays, and conversions from Matrix. Ondrej -- You received this message because you are subscribed to the Google Groups "sympy" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/sympy?hl=en.
