SciPy API¶
Importing from SciPy¶
In Python the distinction between what is the public API of a library and what are private implementation details is not always clear. Unlike in other languages like Java, it is possible in Python to access “private” function or objects. Occasionally this may be convenient, but be aware that if you do so your code may break without warning in future releases. Some widely understood rules for what is and isn’t public in Python are:
Methods / functions / classes and module attributes whose names begin with a leading underscore are private.
If a class name begins with a leading underscore, none of its members are public, whether or not they begin with a leading underscore.
If a module name in a package begins with a leading underscore none of its members are public, whether or not they begin with a leading underscore.
If a module or package defines
__all__
, that authoritatively defines the public interface.If a module or package doesn’t define
__all__
, then all names that don’t start with a leading underscore are public.
Note
Reading the above guidelines one could draw the conclusion that every private module or object starts with an underscore. This is not the case; the presence of underscores do mark something as private, but the absence of underscores do not mark something as public.
In SciPy there are modules whose names don’t start with an underscore, but that should be considered private. To clarify which modules these are, we define below what the public API is for SciPy, and give some recommendations for how to import modules/functions/objects from SciPy.
Guidelines for importing functions from SciPy¶
The scipy namespace itself only contains functions imported from numpy. These functions still exist for backwards compatibility, but should be imported from numpy directly.
Everything in the namespaces of scipy submodules is public. In general, it is
recommended to import functions from submodule namespaces. For example, the
function curve_fit
(defined in scipy/optimize/minpack.py) should be
imported like this:
from scipy import optimize
result = optimize.curve_fit(...)
This form of importing submodules is preferred for all submodules except
scipy.io
(because io
is also the name of a module in the Python
stdlib):
from scipy import interpolate
from scipy import integrate
import scipy.io as spio
In some cases, the public API is one level deeper. For example, the
scipy.sparse.linalg
module is public, and the functions it contains are not
available in the scipy.sparse
namespace. Sometimes it may result in more
easily understandable code if functions are imported from one level deeper.
For example, in the following it is immediately clear that lomax
is a
distribution if the second form is chosen:
# first form
from scipy import stats
stats.lomax(...)
# second form
from scipy.stats import distributions
distributions.lomax(...)
In that case, the second form can be chosen if it is documented in the next section that the submodule in question is public.
API definition¶
Every submodule listed below is public. That means that these submodules are unlikely to be renamed or changed in an incompatible way, and if that is necessary, a deprecation warning will be raised for one SciPy release before the change is made.
-
scipy.io.harwell_boeing
scipy.io.idl
scipy.io.matlab
scipy.io.netcdf
-
scipy.stats.distributions
SciPy structure¶
All SciPy modules should follow the following conventions. In the
following, a SciPy module is defined as a Python package, say
yyy
, that is located in the scipy/ directory.
Ideally, each SciPy module should be as self-contained as possible. That is, it should have minimal dependencies on other packages or modules. Even dependencies on other SciPy modules should be kept to a minimum. A dependency on NumPy is of course assumed.
Directory
yyy/
contains:A file
setup.py
that definesconfiguration(parent_package='',top_path=None)
function fornumpy.distutils
.A directory
tests/
that contains filestest_<name>.py
corresponding to modulesyyy/<name>{.py,.so,/}
.
Private modules should be prefixed with an underscore
_
, for instanceyyy/_somemodule.py
.User-visible functions should have good documentation following the NumPy documentation style.
The
__init__.py
of the module should contain the main reference documentation in its docstring. This is connected to the Sphinx documentation underdoc/
via Sphinx’s automodule directive.The reference documentation should first give a categorized list of the contents of the module using
autosummary::
directives, and after that explain points essential for understanding the use of the module.Tutorial-style documentation with extensive examples should be separate and put under
doc/source/tutorial/
.
See the existing SciPy submodules for guidance.
For further details on NumPy distutils, see NumPy Distutils - User’s Guide.