Řyvind Jensen wrote:
Hi Alan and Comer,
As Andy mentioned I am working on code generation. Right now I focus
on array arguments, trying to generate code that will loop over arrays
and perform calculations on the array elements. The plan is described
here http://code.google.com/p/sympy/wiki/CodeGenerationIdeas .
It is very cool that you work on tensors, and I think that code
generation from expressions with tensors would be a perfect challenge
for my code generation efforts. I'll definitely try your code, and
see what I can do w.r.t. code generation.
I have two questions for you already:
1) The abstract tensor classes are not subclasses of Expr, why is
that? Couldn't that limit what you can do with the module? Do you
think it will be very difficult to change this later if needed?
2) For the array argument code generation I plan to use Index objects
that optionally know their own range so that this information can be
used to code loops over arbitrary ranges. Would it be possible to
implement covariant and contravariant indices as subclasses of my
Index objects? These Index objects are similar to Ondrej's old code
that you asked about in
http://groups.google.com/group/sympy/browse_thread/thread/b3f6736ff2e9cfa5#
I have uploaded a first implementation of the Index objects here:
http://github.com/jegerjensen/sympy/tree/indexed
Řyvind
On 9 Jun, 23:29, Alan Bromborsky <[email protected]> wrote:
Aaron S. Meurer wrote:
You should clone from the official repo, not github, and add github as a remote
to push to, i.e., do:
git clone git://git.sympy.org/sympy.git
git remote add github [email protected]:youname/sympy.git
git push github yourbranch
If you already have a clone of the sympy repository (i.e., you were working in a git repository), you can skip the first step.
Aaron Meurer
On Jun 9, 2010, at 1:14 PM, Andy Ray Terrel wrote:
On github would I add a clone of my complete modified sympy distribution or
only the changes/additions that I have made?
AFAIK, you should go to the sympy github repo [0], hit the fork
button. Then push your dev branch to your fork. For me this would be
git clone [email protected]:aterrel/sympy.git
git push origin foo_branch:foo_branch
You may have to first push to your master if you are up to date with
the sympy.org repo because the github sympy repo is a bit behind.
After that let us know where to pull from.
-- Andy
[0]http://github.com/sympy/sympy
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Thank you that should do it. As soon as the documentation is
acceptable, but not complete, I will add to github.
The is an explanation of how the abstract tensors are realized in the
documentation of sympy-tensor. Just go to doc and make html. I was
planning to make the
abstract tensors concrete by specifying a vector space dimension and
stuffing appropriate numpy arrays with sympy symbols and functions.
numpy already has the tensor product (numpy.multiply.outer()) and tensor
contraction(numpy.tensordot()) and scalar multiplication and tensor
addition/subtraction.
I don't know enough about the inner workings of sympy to know what I
should subclass Tensor to Expr (I did not do it with the MV, multivector
class, in the geometric algebra module), please explain. What I do need
to do is subclass Tensor to object or I won't be able to make the sympy
printing system work with it.
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