[SciPy-user] Update to my SciPy document
Dave Kuhlman
dkuhlman at rexx.com
Fri Jun 23 19:51:22 EDT 2006
On Thu, Jun 22, 2006 at 09:11:34PM +0200, Francesc Altet wrote:
[snip]
>
> - 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
--
Dave Kuhlman
http://www.rexx.com/~dkuhlman
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