Add lazy importing for a 2x speedup importing numpy

Makefile

@@ -28,6 +28,7 @@ NUMPY_LIBS=\
   $(NUMPY_ROOT)/fft/fftpack_lite.so \
 	$(NUMPY_ROOT)/random/mtrand.so
 
+SITEPACKAGES=root/lib/python$(PYMINOR)/site-packages
 
 all: build/pyodide.asm.html build/pyodide.js
 
@@ -58,15 +59,23 @@ clean:
 	$(CXX) --bind -o $@ $< $(CXXFLAGS)
 
 
-root/.built: $(CPYTHONLIB) $(NUMPY_LIBS)
+root/.built: \
+		$(CPYTHONLIB) \
+		$(NUMPY_LIBS) \
+		src/lazy_import.py \
+		src/sitecustomize.py
+	[ -d root ] && rm -rf root
 	mkdir -p root/lib
 	cp -a $(CPYTHONLIB)/ root/lib
-	cp -a numpy/build/numpy root/lib/python$(PYMINOR)/site-packages
-	rm -fr root/lib/python$(PYMINOR)/site-packages/numpy/distutils
 	( \
 		cd root/lib/python$(PYMINOR); \
 		rm -fr test distutils ensurepip idlelib __pycache__ tkinter; \
 	)
+	cp -a numpy/build/numpy $(SITEPACKAGES)
+	rm -fr $(SITEPACKAGES)/numpy/distutils
+	mkdir $(SITEPACKAGES)/lazy_import
+	cp src/lazy_import.py $(SITEPACKAGES)
+	cp src/sitecustomize.py $(SITEPACKAGES)
 	touch root/.built
 
 

src/lazy_import.py

+# This is a fork of lazy_import-0.2.2 by Manuel Nuno Melo to make the
+# following changes:
+#   - Remove dependency on six (this is Python 3 only)
+#   - Remove the logging functionality
+#   - Hardcode the version number
+
+# -*- Mode: python; tab-width: 4; indent-tabs-mode:nil; coding:utf-8 -*-
+# vim: tabstop=4 expandtab shiftwidth=4 softtabstop=4
+#
+# lazy_import --- https://github.com/mnmelo/lazy_import
+# Copyright (C) 2017-2018 Manuel Nuno Melo
+#
+# This file is part of lazy_import.
+#
+#  lazy_import is free software: you can redistribute it and/or modify
+#  it under the terms of the GNU General Public License as published by
+#  the Free Software Foundation, either version 3 of the License, or
+#  (at your option) any later version.
+#
+#  lazy_import is distributed in the hope that it will be useful,
+#  but WITHOUT ANY WARRANTY; without even the implied warranty of
+#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#  GNU General Public License for more details.
+#
+#  You should have received a copy of the GNU General Public License
+#  along with lazy_import.  If not, see <http://www.gnu.org/licenses/>.
+#
+# lazy_import was based on code from the importing module from the PEAK
+# package (see <http://peak.telecommunity.com/DevCenter/Importing>). The PEAK
+# package is released under the following license, reproduced here:
+#
+#  Copyright (C) 1996-2004 by Phillip J. Eby and Tyler C. Sarna.
+#  All rights reserved.  This software may be used under the same terms
+#  as Zope or Python.  THERE ARE ABSOLUTELY NO WARRANTIES OF ANY KIND.
+#  Code quality varies between modules, from "beta" to "experimental
+#  pre-alpha".  :)
+#
+# Code pertaining to lazy loading from PEAK importing was included in
+# lazy_import, modified in a number of ways. These are detailed in the
+# CHANGELOG file of lazy_import. Changes mainly involved Python 3
+# compatibility, extension to allow customizable behavior, and added
+# functionality (lazy importing of callable objects).
+#
+
+"""
+Lazy module loading
+===================
+
+Functions and classes for lazy module loading that also delay import errors.
+Heavily borrowed from the `importing`_ module.
+
+.. _`importing`: http://peak.telecommunity.com/DevCenter/Importing
+
+Files and directories
+---------------------
+
+.. autofunction:: module
+.. autofunction:: callable
+
+"""
+
+__all__ = ['lazy_module', 'lazy_callable', 'lazy_function', 'lazy_class',
+           'LazyModule', 'LazyCallable', 'module_basename', '_MSG',
+           '_MSG_CALLABLE']
+
+from types import ModuleType
+import sys
+from importlib._bootstrap import _ImportLockContext
+from importlib import reload as reload_module
+
+# Adding a __spec__ doesn't really help. I'll leave the code here in case
+# future python implementations start relying on it.
+#try:
+#    from importlib.machinery import ModuleSpec
+#except ImportError:
+#    ModuleSpec = None
+
+__version__ = '0.2.2-pyodide'
+
+
+################################
+# Module/function registration #
+################################
+
+#### Lazy classes ####
+
+class LazyModule(ModuleType):
+    """Class for lazily-loaded modules that triggers proper loading on access.
+
+    Instantiation should be made from a subclass of :class:`LazyModule`, with
+    one subclass per instantiated module. Regular attribute set/access can then
+    be recovered by setting the subclass's :meth:`__getattribute__` and
+    :meth:`__setattribute__` to those of :class:`types.ModuleType`.
+    """
+    # peak.util.imports sets __slots__ to (), but it seems pointless because
+    # the base ModuleType doesn't itself set __slots__.
+    def __getattribute__(self, attr):
+        #traceback.print_stack()
+        # IPython tries to be too clever and constantly inspects, asking for
+        #  modules' attrs, which causes premature module loading and unesthetic
+        #  internal errors if the lazily-loaded module doesn't exist.
+        if (run_from_ipython()
+            and (attr.startswith(("__", "_ipython"))
+                 or attr == "_repr_mimebundle_")
+            and module_basename(_caller_name()) in ('inspect', 'IPython')):
+                raise AttributeError
+        if not attr in ('__name__','__class__','__spec__'):
+            # __name__ and __class__ yield their values from the LazyModule;
+            # __spec__ causes an AttributeError. Maybe in the future it will be
+            # necessary to return an actual ModuleSpec object, but it works as
+            # it is without that now.
+
+            # If it's an already-loaded submodule, we return it without
+            # triggering a full loading
+            try:
+                return sys.modules[self.__name__+"."+attr]
+            except KeyError:
+                pass
+            # Check if it's one of the lazy callables
+            try:
+                return type(self)._lazy_import_callables[attr]
+            except (AttributeError, KeyError) as err:
+                #traceback.print_stack()
+                _load_module(self)
+        return super(LazyModule, self).__getattribute__(attr)
+
+    def __setattr__(self, attr, value):
+        _load_module(self)
+        return super(LazyModule, self).__setattr__(attr, value)
+
+
+class LazyCallable(object):
+    """Class for lazily-loaded callables that triggers module loading on access
+
+    """
+    def __init__(self, module, cname):
+        self.module = module
+        self.modclass = type(self.module)
+        self.cname = cname
+        self.callable = None
+        # Need to save these, since the module-loading gets rid of them
+        self.error_msgs = self.modclass._lazy_import_error_msgs
+        self.error_strings = self.modclass._lazy_import_error_strings
+
+    def __call__(self, *args, **kwargs):
+        # No need to go through all the reloading more than once.
+        if self.callable:
+            return self.callable(*args, **kwargs)
+        try:
+            del self.modclass._lazy_import_callables[self.cname]
+        except (AttributeError, KeyError):
+            pass
+        try:
+            self.callable = getattr(self.module, self.cname)
+        except AttributeError:
+            msg = self.error_msgs['msg_callable']
+            raise AttributeError(
+                msg.format(callable=self.cname, **self.error_strings)) from None
+        except ImportError as err:
+            # Import failed. We reset the dict and re-raise the ImportError.
+            try:
+                self.modclass._lazy_import_callables[self.cname] = self
+            except AttributeError:
+                self.modclass._lazy_import_callables = {self.cname: self}
+            raise err from None
+        else:
+            return self.callable(*args, **kwargs)
+
+
+### Functions ###
+
+def lazy_module(modname, error_strings=None, lazy_mod_class=LazyModule,
+                  level='leaf'):
+    """Function allowing lazy importing of a module into the namespace.
+
+    A lazy module object is created, registered in `sys.modules`, and
+    returned. This is a hollow module; actual loading, and `ImportErrors` if
+    not found, are delayed until an attempt is made to access attributes of the
+    lazy module.
+
+    A handy application is to use :func:`lazy_module` early in your own code
+    (say, in `__init__.py`) to register all modulenames you want to be lazy.
+    Because of registration in `sys.modules` later invocations of
+    `import modulename` will also return the lazy object. This means that after
+    initial registration the rest of your code can use regular pyhon import
+    statements and retain the lazyness of the modules.
+
+    Parameters
+    ----------
+    modname : str
+         The module to import.
+    error_strings : dict, optional
+         A dictionary of strings to use when module-loading fails. Key 'msg'
+         sets the message to use (defaults to :attr:`lazy_import._MSG`). The
+         message is formatted using the remaining dictionary keys. The default
+         message informs the user of which module is missing (key 'module'),
+         what code loaded the module as lazy (key 'caller'), and which package
+         should be installed to solve the dependency (key 'install_name').
+         None of the keys is mandatory and all are given smart names by default.
+    lazy_mod_class: type, optional
+         Which class to use when instantiating the lazy module, to allow
+         deep customization. The default is :class:`LazyModule` and custom
+         alternatives **must** be a subclass thereof.
+    level : str, optional
+         Which submodule reference to return. Either a reference to the 'leaf'
+         module (the default) or to the 'base' module. This is useful if you'll
+         be using the module functionality in the same place you're calling
+         :func:`lazy_module` from, since then you don't need to run `import`
+         again. Setting *level* does not affect which names/modules get
+         registered in `sys.modules`.
+         For *level* set to 'base' and *modulename* 'aaa.bbb.ccc'::
+
+            aaa = lazy_import.lazy_module("aaa.bbb.ccc", level='base')
+            # 'aaa' becomes defined in the current namespace, with
+            #  (sub)attributes 'aaa.bbb' and 'aaa.bbb.ccc'.
+            # It's the lazy equivalent to:
+            import aaa.bbb.ccc
+
+        For *level* set to 'leaf'::
+
+            ccc = lazy_import.lazy_module("aaa.bbb.ccc", level='leaf')
+            # Only 'ccc' becomes set in the current namespace.
+            # Lazy equivalent to:
+            from aaa.bbb import ccc
+
+    Returns
+    -------
+    module
+        The module specified by *modname*, or its base, depending on *level*.
+        The module isn't immediately imported. Instead, an instance of
+        *lazy_mod_class* is returned. Upon access to any of its attributes, the
+        module is finally loaded.
+
+    Examples
+    --------
+    >>> import lazy_import, sys
+    >>> np = lazy_import.lazy_module("numpy")
+    >>> np
+    Lazily-loaded module numpy
+    >>> np is sys.modules['numpy']
+    True
+    >>> np.pi # This causes the full loading of the module ...
+    3.141592653589793
+    >>> np # ... and the module is changed in place.
+    <module 'numpy' from '/usr/local/lib/python/site-packages/numpy/__init__.py'>
+
+    >>> import lazy_import, sys
+    >>> # The following succeeds even when asking for a module that's not available
+    >>> missing = lazy_import.lazy_module("missing_module")
+    >>> missing
+    Lazily-loaded module missing_module
+    >>> missing is sys.modules['missing_module']
+    True
+    >>> missing.some_attr # This causes the full loading of the module, which now fails.
+    ImportError: __main__ attempted to use a functionality that requires module missing_module, but it couldn't be loaded. Please install missing_module and retry.
+
+    See Also
+    --------
+    :func:`lazy_callable`
+    :class:`LazyModule`
+
+    """
+    if error_strings is None:
+        error_strings = {}
+    _set_default_errornames(modname, error_strings)
+
+    mod = _lazy_module(modname, error_strings, lazy_mod_class)
+    if level == 'base':
+        return sys.modules[module_basename(modname)]
+    elif level == 'leaf':
+        return mod
+    else:
+        raise ValueError("Parameter 'level' must be one of ('base', 'leaf')")
+
+
+def _lazy_module(modname, error_strings, lazy_mod_class):
+    with _ImportLockContext():
+        fullmodname = modname
+        fullsubmodname = None
+        # ensure parent module/package is in sys.modules
+        # and parent.modname=module, as soon as the parent is imported
+        while modname:
+            try:
+                mod = sys.modules[modname]
+                # We reached a (base) module that's already loaded. Let's stop
+                # the cycle. Can't use 'break' because we still want to go
+                # through the fullsubmodname check below.
+                modname = ''
+            except KeyError:
+                err_s = error_strings.copy()
+                err_s.setdefault('module', modname)
+
+                class _LazyModule(lazy_mod_class):
+                    _lazy_import_error_msgs = {'msg': err_s.pop('msg')}
+                    try:
+                        _lazy_import_error_msgs['msg_callable'] = \
+                                err_s.pop('msg_callable')
+                    except KeyError:
+                        pass
+                    _lazy_import_error_strings = err_s
+                    _lazy_import_callables = {}
+                    _lazy_import_submodules = {}
+
+                    def __repr__(self):
+                        return "Lazily-loaded module {}".format(self.__name__)
+                # A bit of cosmetic, to make AttributeErrors read more natural
+                _LazyModule.__name__ = 'module'
+                # Actual module instantiation
+                mod = sys.modules[modname] = _LazyModule(modname)
+                # No need for __spec__. Maybe in the future.
+                #if ModuleSpec:
+                #    ModuleType.__setattr__(mod, '__spec__',
+                #            ModuleSpec(modname, None))
+            if fullsubmodname:
+                submod = sys.modules[fullsubmodname]
+                ModuleType.__setattr__(mod, submodname, submod)
+                _LazyModule._lazy_import_submodules[submodname] = submod
+            fullsubmodname = modname
+            modname, _, submodname = modname.rpartition('.')
+        return sys.modules[fullmodname]
+
+
+def lazy_callable(modname, *names, **kwargs):
+    """Performs lazy importing of one or more callables.
+
+    :func:`lazy_callable` creates functions that are thin wrappers that pass
+    any and all arguments straight to the target module's callables. These can
+    be functions or classes. The full loading of that module is only actually
+    triggered when the returned lazy function itself is called. This lazy
+    import of the target module uses the same mechanism as
+    :func:`lazy_module`.
+
+    If, however, the target module has already been fully imported prior
+    to invocation of :func:`lazy_callable`, then the target callables
+    themselves are returned and no lazy imports are made.
+
+    :func:`lazy_function` and :func:`lazy_function` are aliases of
+    :func:`lazy_callable`.
+
+    Parameters
+    ----------
+    modname : str
+         The base module from where to import the callable(s) in *names*,
+         or a full 'module_name.callable_name' string.
+    names : str (optional)
+         The callable name(s) to import from the module specified by *modname*.
+         If left empty, *modname* is assumed to also include the callable name
+         to import.
+    error_strings : dict, optional
+         A dictionary of strings to use when reporting loading errors (either a
+         missing module, or a missing callable name in the loaded module).
+         *error_string* follows the same usage as described under
+         :func:`lazy_module`, with the exceptions that 1) a further key,
+         'msg_callable', can be supplied to be used as the error when a module
+         is successfully loaded but the target callable can't be found therein
+         (defaulting to :attr:`lazy_import._MSG_CALLABLE`); 2) a key 'callable'
+         is always added with the callable name being loaded.
+    lazy_mod_class : type, optional
+         See definition under :func:`lazy_module`.
+    lazy_call_class : type, optional
+         Analogously to *lazy_mod_class*, allows setting a custom class to
+         handle lazy callables, other than the default :class:`LazyCallable`.
+
+    Returns
+    -------
+    wrapper function or tuple of wrapper functions
+        If *names* is passed, returns a tuple of wrapper functions, one for
+        each element in *names*.
+        If only *modname* is passed it is assumed to be a full
+        'module_name.callable_name' string, in which case the wrapper for the
+        imported callable is returned directly, and not in a tuple.
+
+    Notes
+    -----
+    Unlike :func:`lazy_module`, which returns a lazy module that eventually
+    mutates into the fully-functional version, :func:`lazy_callable` only
+    returns thin wrappers that never change. This means that the returned
+    wrapper object never truly becomes the one under the module's namespace,
+    even after successful loading of the module in *modname*. This is fine for
+    most practical use cases, but may break code that relies on the usage of
+    the returned objects oter than calling them. One such example is the lazy
+    import of a class: it's fine to use the returned wrapper to instantiate an
+    object, but it can't be used, for instance, to subclass from.
+
+    Examples
+    --------
+    >>> import lazy_import, sys
+    >>> fn = lazy_import.lazy_callable("numpy.arange")
+    >>> sys.modules['numpy']
+    Lazily-loaded module numpy
+    >>> fn(10)
+    array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])
+    >>> sys.modules['numpy']
+    <module 'numpy' from '/usr/local/lib/python3.5/site-packages/numpy/__init__.py'>
+
+    >>> import lazy_import, sys
+    >>> cl = lazy_import.lazy_callable("numpy.ndarray") # a class
+    >>> obj = cl([1, 2]) # This works OK (and also triggers the loading of numpy)
+    >>> class MySubclass(cl): # This fails because cls is just a wrapper,
+    >>>     pass              #  not an actual class.
+
+    See Also
+    --------
+    :func:`lazy_module`
+    :class:`LazyCallable`
+    :class:`LazyModule`
+
+    """
+    if not names:
+        modname, _, name = modname.rpartition(".")
+    lazy_mod_class = _setdef(kwargs, 'lazy_mod_class', LazyModule)
+    lazy_call_class = _setdef(kwargs, 'lazy_call_class', LazyCallable)
+    error_strings = _setdef(kwargs, 'error_strings', {})
+    _set_default_errornames(modname, error_strings, call=True)
+
+    if not names:
+        # We allow passing a single string as 'modname.callable_name',
+        # in which case the wrapper is returned directly and not as a list.
+        return _lazy_callable(modname, name, error_strings.copy(),
+                                lazy_mod_class, lazy_call_class)
+    return tuple(_lazy_callable(modname, cname, error_strings.copy(),
+                        lazy_mod_class, lazy_call_class) for cname in names)
+
+lazy_function = lazy_class = lazy_callable
+
+def _lazy_callable(modname, cname, error_strings,
+                     lazy_mod_class, lazy_call_class):
+    # We could do most of this in the LazyCallable __init__, but here we can
+    # pre-check whether to actually be lazy or not.
+    module = _lazy_module(modname, error_strings, lazy_mod_class)
+    modclass = type(module)
+    if (issubclass(modclass, LazyModule) and
+        hasattr(modclass, '_lazy_import_callables')):
+        modclass._lazy_import_callables.setdefault(
+            cname, lazy_call_class(module, cname))
+    return getattr(module, cname)
+
+
+#######################
+# Real module loading #
+#######################
+
+def _load_module(module):
+    """Ensures that a module, and its parents, are properly loaded
+
+    """
+    modclass = type(module)
+    # We only take care of our own LazyModule instances
+    if not issubclass(modclass, LazyModule):
+        raise TypeError("Passed module is not a LazyModule instance.")
+    with _ImportLockContext():
+        parent, _, modname = module.__name__.rpartition('.')
+        # We first identify whether this is a loadable LazyModule, then we
+        # strip as much of lazy_import behavior as possible (keeping it cached,
+        # in case loading fails and we need to reset the lazy state).
+        if not hasattr(modclass, '_lazy_import_error_msgs'):
+            # Alreay loaded (no _lazy_import_error_msgs attr). Not reloading.
+            return
+        # First, ensure the parent is loaded (using recursion; *very* unlikely
+        # we'll ever hit a stack limit in this case).
+        modclass._LOADING = True
+        try:
+            if parent:
+                setattr(sys.modules[parent], modname, module)
+            if not hasattr(modclass, '_LOADING'):
+                # We've been loaded by the parent. Let's bail.
+                return
+            cached_data = _clean_lazymodule(module)
+            try:
+                # Get Python to do the real import!
+                reload_module(module)
+            except:
+                # Loading failed. We reset our lazy state.
+                _reset_lazymodule(module, cached_data)
+                raise
+            else:
+                # Successful load
+                delattr(modclass, '_LOADING')
+                _reset_lazy_submod_refs(module)
+
+        except (AttributeError, ImportError) as err:
+            #traceback.print_stack()
+            # Under Python 3 reloading our dummy LazyModule instances causes an
+            # AttributeError if the module can't be found. Would be preferrable
+            # if we could always rely on an ImportError. As it is we vet the
+            # AttributeError as thoroughly as possible.
+            if (isinstance(err, AttributeError) and not
+                err.args[0] == "'NoneType' object has no attribute 'name'"):
+                # Not the AttributeError we were looking for.
+                raise
+            msg = modclass._lazy_import_error_msgs['msg']
+            raise ImportError(
+                msg.format(**modclass._lazy_import_error_strings)) from None
+
+
+##############################
+# Helper functions/constants #
+##############################
+
+_MSG = ("{caller} attempted to use a functionality that requires module "
+        "{module}, but it couldn't be loaded. Please install {install_name} "
+        "and retry.")
+
+_MSG_CALLABLE = ("{caller} attempted to use a functionality that requires "
+           "{callable}, of module {module}, but it couldn't be found in that "
+           "module. Please install a version of {install_name} that has "
+           "{module}.{callable} and retry.")
+
+_CLS_ATTRS = ("_lazy_import_error_strings", "_lazy_import_error_msgs",
+              "_lazy_import_callables", "_lazy_import_submodules", "__repr__")
+
+_DELETION_DICT = ("_lazy_import_submodules",)
+
+def _setdef(argdict, name, defaultvalue):
+    """Like dict.setdefault but sets the default value also if None is present.
+
+    """
+    if not name in argdict or argdict[name] is None:
+        argdict[name] = defaultvalue
+    return argdict[name]
+
+
+def module_basename(modname):
+    return modname.partition('.')[0]
+
+
+def _set_default_errornames(modname, error_strings, call=False):
+    # We don't set the modulename default here because it will change for
+    # parents of lazily imported submodules.
+    error_strings.setdefault('caller', _caller_name(3, default='Python'))
+    error_strings.setdefault('install_name', module_basename(modname))
+    error_strings.setdefault('msg', _MSG)
+    if call:
+        error_strings.setdefault('msg_callable', _MSG_CALLABLE)
+
+
+def _caller_name(depth=2, default=''):
+    """Returns the name of the calling namespace.
+
+    """
+    # the presence of sys._getframe might be implementation-dependent.
+    # It isn't that serious if we can't get the caller's name.
+    try:
+        return sys._getframe(depth).f_globals['__name__']
+    except AttributeError:
+        return default
+
+
+def _clean_lazymodule(module):
+    """Removes all lazy behavior from a module's class, for loading.
+
+    Also removes all module attributes listed under the module's class deletion
+    dictionaries. Deletion dictionaries are class attributes with names
+    specified in `_DELETION_DICT`.
+
+    Parameters
+    ----------
+    module: LazyModule
+
+    Returns
+    -------
+    dict
+        A dictionary of deleted class attributes, that can be used to reset the
+        lazy state using :func:`_reset_lazymodule`.
+    """
+    modclass = type(module)
+    _clean_lazy_submod_refs(module)
+
+    modclass.__getattribute__ = ModuleType.__getattribute__
+    modclass.__setattr__ = ModuleType.__setattr__
+    cls_attrs = {}
+    for cls_attr in _CLS_ATTRS:
+        try:
+            cls_attrs[cls_attr] = getattr(modclass, cls_attr)
+            delattr(modclass, cls_attr)
+        except AttributeError:
+            pass
+    return cls_attrs
+
+
+def _clean_lazy_submod_refs(module):
+    modclass = type(module)
+    for deldict in _DELETION_DICT:
+        try:
+            delnames = getattr(modclass, deldict)
+        except AttributeError:
+            continue
+        for delname in delnames:
+            try:
+                super(LazyModule, module).__delattr__(delname)
+            except AttributeError:
+                # Maybe raise a warning?
+                pass
+
+
+def _reset_lazymodule(module, cls_attrs):
+    """Resets a module's lazy state from cached data.
+
+    """
+    modclass = type(module)
+    del modclass.__getattribute__
+    del modclass.__setattr__
+    try:
+        del modclass._LOADING
+    except AttributeError:
+        pass
+    for cls_attr in _CLS_ATTRS:
+        try:
+            setattr(modclass, cls_attr, cls_attrs[cls_attr])
+        except KeyError:
+            pass
+    _reset_lazy_submod_refs(module)
+
+
+def _reset_lazy_submod_refs(module):
+    modclass = type(module)
+    for deldict in _DELETION_DICT:
+        try:
+            resetnames = getattr(modclass, deldict)
+        except AttributeError:
+            continue
+        for name, submod in resetnames.items():
+            super(LazyModule, module).__setattr__(name, submod)
+
+def run_from_ipython():
+    # Taken from https://stackoverflow.com/questions/5376837
+    try:
+        __IPYTHON__
+        return True
+    except NameError:
+        return False

src/sitecustomize.py

+import lazy_import
+
+print("Setting up lazy importing...")
+
+lazy_import.lazy_module("numpy.linalg")
+lazy_import.lazy_module("numpy.fft")
+lazy_import.lazy_module("numpy.polynomial")
+lazy_import.lazy_module("numpy.random")
+lazy_import.lazy_module("numpy.ctypeslib")