modelparameters.sympy.external package

Submodules

modelparameters.sympy.external.importtools module

Tools to assist importing optional external modules.

modelparameters.sympy.external.importtools.import_module(module, min_module_version=None, min_python_version=None, warn_not_installed=None, warn_old_version=None, module_version_attr='__version__', module_version_attr_call_args=None, __import__kwargs={}, catch=())

Import and return a module if it is installed.

If the module is not installed, it returns None.

A minimum version for the module can be given as the keyword argument min_module_version. This should be comparable against the module version. By default, module.__version__ is used to get the module version. To override this, set the module_version_attr keyword argument. If the attribute of the module to get the version should be called (e.g., module.version()), then set module_version_attr_call_args to the args such that module.module_version_attr(*module_version_attr_call_args) returns the module’s version.

If the module version is less than min_module_version using the Python < comparison, None will be returned, even if the module is installed. You can use this to keep from importing an incompatible older version of a module.

You can also specify a minimum Python version by using the min_python_version keyword argument. This should be comparable against sys.version_info.

If the keyword argument warn_not_installed is set to True, the function will emit a UserWarning when the module is not installed.

If the keyword argument warn_old_version is set to True, the function will emit a UserWarning when the library is installed, but cannot be imported because of the min_module_version or min_python_version options.

Note that because of the way warnings are handled, a warning will be emitted for each module only once. You can change the default warning behavior by overriding the values of WARN_NOT_INSTALLED and WARN_OLD_VERSION in sympy.external.importtools. By default, WARN_NOT_INSTALLED is False and WARN_OLD_VERSION is True.

This function uses __import__() to import the module. To pass additional options to __import__(), use the __import__kwargs keyword argument. For example, to import a submodule A.B, you must pass a nonempty fromlist option to __import__. See the docstring of __import__().

This catches ImportError to determine if the module is not installed. To catch additional errors, pass them as a tuple to the catch keyword argument.

Examples

>>> from ..external import import_module

>>> numpy = import_module('numpy')

>>> numpy = import_module('numpy', min_python_version=(2, 7),
... warn_old_version=False)

>>> numpy = import_module('numpy', min_module_version='1.5',
... warn_old_version=False) # numpy.__version__ is a string

>>> # gmpy does not have __version__, but it does have gmpy.version()

>>> gmpy = import_module('gmpy', min_module_version='1.14',
... module_version_attr='version', module_version_attr_call_args=(),
... warn_old_version=False)

>>> # To import a submodule, you must pass a nonempty fromlist to
>>> # __import__().  The values do not matter.
>>> p3 = import_module('mpl_toolkits.mplot3d',
... __import__kwargs={'fromlist':['something']})

>>> # matplotlib.pyplot can raise RuntimeError when the display cannot be opened
>>> matplotlib = import_module('matplotlib',
... __import__kwargs={'fromlist':['pyplot']}, catch=(RuntimeError,))

Module contents

Unified place for determining if external dependencies are installed or not.

You should import all external modules using the import_module() function.

For example

>>> from ..external import import_module
>>> numpy = import_module('numpy')

If the resulting library is not installed, or if the installed version is less than a given minimum version, the function will return None. Otherwise, it will return the library. See the docstring of import_module() for more information.