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- .. _defaults:
- -----------------------------
- Defaults for bcolz operation
- -----------------------------
- You can tailor the behaviour of bcolz by changing the values of
- certain some special top level variables whose defaults are listed
- here. You can change these values in two ways:
- * In your program: the changes will be temporary. For example::
- bcolz.defaults.out_flavor = "numpy"
- * Manually modify the ``defaults.py`` module of the bcolz package: the
- changes will be persistent. For example, replace::
- defaults.out_flavor = "bcolz"
- by::
- defaults.out_flavor = "numpy"
- Generally, only the former is needed.
- Defaults in contexts
- ====================
- bcolz allows to set short-lived defaults in contexts. For example::
- with bcolz.defaults_ctx(vm="python", cparams=bcolz.cparams(clevel=0)):
- cout = bcolz.eval("(x + 1) < 0")
- means that the `bcolz.eval` operation will be made using a "python"
- virtual machine and no compression for the `cout` output.
- List of default values
- ======================
- .. py:attribute:: out_flavor
- The flavor for the output object in :py:func:`eval` and others
- that call this indirectly. It can be 'bcolz' or 'numpy'. Default
- is 'bcolz'.
- .. py:attribute:: vm
- The virtual machine to be used in computations (via
- :py:func:`eval`). It can be 'python', 'numexpr' or 'dask'.
- Default is 'numexpr', if installed. If not, 'dask' is used, if
- installed. And if neither of these are installed, then the
- 'python' interpreter is used (via numpy).
- .. py:attribute:: cparams
- :noindex:
- The defaults for parameters used in compression (dict). The
- default is {'clevel': 5, 'shuffle': True, 'cname': 'lz4',
- quantize: 0}.
- See Also:
- :py:func:`cparams.setdefaults`
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