# Release notes for PyTables 3.2 series

Author: | PyTables Developers
Contact: | pytables-dev@googlegroups.com

## Changes from 3.1.1 to 3.2.0

### Improvements

- The nrowsinbuf is better computed now for EArray/CArray having a small chunkshape in the main dimension. Fixes #285.

- PyTables should be installable very friendly via pip, including NumPy being installed automatically in the unlikely case it is not yet installed in the system. Thanks to Andrea Bedini.

- setup.py has been largely simplified and now it requires setuptools. Although we think this is a good step, please keep us informed this is breaking some installation in a very bad manner.

- setup.py now is able to used pkg-config, if available, to locate required libraries (hdf5, bzip2, etc.). The use of pkg-config can be controlled via setup.py command line flags or via environment variables. Please refer to the installation guide (in the User Manual) for details. Closes gh-442.

- It is now possible to create a new node whose parent is a softlink to another group (see gh-422). Thanks to Alistair Muldal.

- `link.SoftLink` objects no longer need to be explicitly dereferenced. Methods and attributes of the linked object are now automatically accessed when the user acts on a soft-link (see gh-399). Thanks to Alistair Muldal.

- Now ptrepack recognizes hardlinks and replicates them in the output (repacked) file. This saves disk space and makes repacked files more conformal to the original one. Closes gh-380.

- New pttree script for printing HDF5 file contents as a pretty ASCII tree (closes gh-400). Thanks to Alistair Muldal.

- The internal Blosc library has been downgraded to version 1.4.4. This is in order to still allow using multiple threads inside Blosc, even on multithreaded applications (see gh-411, gh-412, gh-437 and gh-448).

- The `print_versions()` function now also reports the version of compression libraries used by Blosc.

- Now the `setup.py` tries to use the ‘-march=native’ C flag by default. In falls back on ‘-msse2’ if ‘-march=native’ is not supported by the compiler. Closes gh-379.

- Fixed a spurious unicode comparison warning (closes gh-372 and gh-373).

- Improved handling of empty string attributes. In previous versions of PyTables empty string were stored as scalar HDF5 attributes having size 1 and value ‘0’ (an empty null terminated string). Now empty string are stored as HDF5 attributes having zero size

- Added a new cookbook recipe and a couple of examples for simple threading with PyTables.

- The redundant `utilsextension.get_indices()` function has been eliminated (replaced by `slice.indices()`). Closes gh-195.

- Allow negative indices in point selection (closes gh-360)

- Index wasn’t being used if it claimed there were no results. Closes gh-351 (see also gh-353)

- Atoms and Col types are no longer generated dynamically so now it is easier for IDEs and static analysis tool to handle them (closes gh-345)

- The keysort functions in idx-opt.c have been cythonised using fused types. The perfomance is mostly unchanged, but the code is much more simpler now. Thanks to Andrea Bedini.

- Small unit tests re-factoring:

  - `print_versions()` and `tests.common.print_heavy()` functions

      moved to the `tests.common` module

  - always use `print_versions()` when test modules are called as scripts

  - use the unittest2 package in Python 2.6.x

  - removed internal machinery used to replicate unittest2 features

  - always use `tests.common.PyTablesTestCase` as base class for all test cases

  - code of the old `tasts.common.cleanup()` function has been moved to `tests.common.PyTablesTestCase.tearDown()` method

  - new implementation of `tests.common.PyTablesTestCase.assertWarns()` compatible with the one provided by the standard `unittest` module in Python >= 3.2

  - use `tests.common.PyTablesTestCase.assertWarns()` as context manager when appropriate

  - use the `unittest.skipIf()` decorator when appropriate

  - new :class:tests.comon.TestFileMixin: class

### Bugs fixed

- Fixed compatibility problems with numpy 1.9 and 1.10-dev (closes gh-362 and gh-366)
- Fixed compatibility with Cython >= 0.20 (closes gh-386 and gh-387)
- Fixed support for unicode node names in LRU cache (only Python 2 was affected). Closes gh-367 and gh-369.
- Fixed support for unicode node titles (only Python 2 was affected). Closes gh-370 and gh-374.
- Fixed a bug that caused the silent truncation of unicode attributes containing the ‘0’ character. Closes gh-371.
- Fixed `descr_from_dtype()` to work as expected with complex types. Closes gh-381.
- Fixed the `tests.test_basics.ThreadingTestCase` test case. Closes gh-359.
- Fix incomplete results when performing the same query twice and exhausting the second iterator before the first. The first one writes incomplete results to seqcache (gh-353)
- Fix false results potentially going to seqcache if `tableextension.Row.update()` is used during iteration (see gh-353)
- Fix `Column.create_csindex()` when there’s NaNs
- Fixed handling of unicode file names on windows (closes gh-389)
- No longer not modify `sys.argv` at import time (closes gh-405)
- Fixed a performance issue on NFS (closes gh-402)
- Fixed a nasty problem affecting results of indexed queries. Closes gh-319 and probably gh-419 too.
- Fixed another problem affecting results of indexed queries too. Closes gh-441.
- Replaced “len(xrange(start, stop, step))” -> “len(xrange(0, stop - start, step))” to fix issues with large row counts with Python 2.x. Fixes #447.

### Other changes

- Cython is not a hard dependency anymore (although developers will need it so as to generated the C extension code).

- The number of threads used by default for numexpr and Blosc operation that was set to the number of available cores have been reduced to 2. This is a much more reasonable setting for not creating too much overhead.

  Enjoy data!

  – The PyTables Developers