[SciPy-user] Update to my SciPy document

Dave Kuhlman dkuhlman at rexx.com
Fri Jun 23 18:51:22 CDT 2006

On Thu, Jun 22, 2006 at 09:11:34PM +0200, Francesc Altet wrote:

> - From PyTables 1.3 on, NumPy (and hence SciPy) arrays are supported right
>  out of the box in Array objects (the ones you are using). So, if you write a
>  NumPy array, you will get a NumPy array (the same goes for Numeric and
>  numarray). In other objects (EArray, VLArray or Table) you can make use of
>  the 'flavor' parameter in constructors to tell PyTables: 'Hey, every time
>  that I read from this object, please, return me an (rec)array with the
>  appropriate flavor'. Of course, PyTables will try hard to avoid doing data
>  copies in conversions (i.e. the array protocol is used whenever possible).

Francesc -

Thanks for updating me on this.  I've shamelessly copied the above
paragraph (with minor edits) into my document.  Thank you.  (But,
please let me know if that bothers you.)

> - The procedure for installation can be simplified somewhat:
> $ tar xvzf orig/pytables-1.3.2.tar.gz
> $ cd pytables-1.3.2
> $ python setup.py build
> $ sudo python setup.py install

I used:

    $ python setup.py build_ext --inplace

instead of:

    $ python setup.py build

because that's what the PyTables README.txt says to do.  If I use
"build" instead of "build_ext", does that mean that I would not
need to install Pyrex?

> - Perhaps a nice feature of PyTables that you could document is its
>  capability to read slices of arrays directly from disk. You can do this by
>  providing the start, stop and step parameters to node.read() method, but it
>  would be more appropriate (specially when dealing with multidimensional
>  data) using the __getitem__ method that expose all the data nodes. Examples:
> node[1]   # Get the first element of potentially multidimensional node
> node[1:4:3]  # Get an slice
> node[1:4:3, 2:10:2, ..., 3]  # The complete syntax for slices is supported.

Slick.  I've added several examples and a note.

Thanks for the help.


Dave Kuhlman

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