Now based on ray, which enables nested parallel computations.

.github/workflows/pytest.yml

@@ -11,9 +11,9 @@ jobs:
         os: [ubuntu-latest, windows-latest, macOS-latest]
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - name: Set up Python ${{ matrix.python-version }}
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@v6
         with:
           python-version: ${{ matrix.python-version }}
       - name: Install

parfor/__init__.py

@@ -1,24 +1,84 @@
 from __future__ import annotations
 
-import sys
-from contextlib import ExitStack
+import logging
+import os
+import warnings
+from contextlib import ExitStack, redirect_stdout, redirect_stderr
 from functools import wraps
 from importlib.metadata import version
-from typing import Any, Callable, Generator, Iterable, Iterator, Sized
-from warnings import warn
+from multiprocessing.shared_memory import SharedMemory
+from traceback import format_exc
+from typing import Any, Callable, Generator, Iterable, Iterator, Sized, Hashable, NoReturn, Optional, Protocol, Sequence
 
+import numpy as np
+import ray
+from numpy.typing import ArrayLike, DTypeLike
 from tqdm.auto import tqdm
 
-from . import gil, nogil
-from .common import Bar, SharedArray, cpu_count
 
-if hasattr(sys, '_is_gil_enabled') and not sys._is_gil_enabled():  # noqa
-    from .nogil import ParPool, PoolSingleton, Task, Worker
-else:
-    from .gil import ParPool, PoolSingleton, Task, Worker
+__version__ = version("parfor")
+cpu_count = int(os.cpu_count())
 
 
-__version__ = version('parfor')
+class Bar(Protocol):
+    def update(self, n: int = 1) -> None: ...
+
+
+class SharedArray(np.ndarray):
+    """Numpy array whose memory can be shared between processes, so that memory use is reduced and changes in one
+    process are reflected in all other processes. Changes are not atomic, so protect changes with a lock to prevent
+    race conditions!
+    """
+
+    def __new__(
+        cls,
+        shape: int | Sequence[int],
+        dtype: DTypeLike = float,
+        shm: str | SharedMemory = None,
+        offset: int = 0,
+        strides: tuple[int, int] = None,
+        order: str = None,
+    ) -> SharedArray:
+        if isinstance(shm, str):
+            shm = SharedMemory(shm)
+        elif shm is None:
+            shm = SharedMemory(create=True, size=np.prod(shape) * np.dtype(dtype).itemsize)  # type: ignore
+        new = super().__new__(cls, shape, dtype, shm.buf, offset, strides, order)
+        new.shm = shm
+        return new
+
+    def __reduce__(
+        self,
+    ) -> tuple[
+        Callable[[int | Sequence[int], DTypeLike, str], SharedArray],
+        tuple[int | tuple[int, ...], np.dtype, str],
+    ]:
+        return self.__class__, (self.shape, self.dtype, self.shm.name)
+
+    def __enter__(self) -> SharedArray:
+        return self
+
+    def __exit__(self, *args: Any, **kwargs: Any) -> None:
+        if hasattr(self, "shm"):
+            self.shm.close()
+            self.shm.unlink()
+
+    def __del__(self) -> None:
+        if hasattr(self, "shm"):
+            self.shm.close()
+
+    def __array_finalize__(self, obj: np.ndarray | None) -> None:
+        if isinstance(obj, np.ndarray) and not isinstance(obj, SharedArray):
+            raise TypeError("view casting to SharedArray is not implemented because right now we need to make a copy")
+
+    @classmethod
+    def from_array(cls, array: ArrayLike) -> SharedArray:
+        """copy existing array into a SharedArray"""
+        array = np.asarray(array)
+        new = cls(array.shape, array.dtype)
+        new[:] = array[:]
+        return new
+
 
 
 class Chunks(Iterable):
@@ -34,14 +94,21 @@ class Chunks(Iterable):
     both ratio and number are given: use ratio
     """
 
-    def __init__(self, *iterables: Iterable[Any] | Sized[Any], size: int = None, number: int = None,
-                 ratio: float = None, length: int = None) -> None:
+    def __init__(
+        self,
+        *iterables: Iterable[Any] | Sized,
+        size: int = None,
+        number: int = None,
+        ratio: float = None,
+        length: int = None,
+    ) -> None:
         if length is None:
             try:
                 length = min(*[len(iterable) for iterable in iterables]) if len(iterables) > 1 else len(iterables[0])
             except TypeError:
-                raise TypeError('Cannot determine the length of the iterables(s), so the length must be provided as an'
-                                ' argument.')
+                raise TypeError(
+                    "Cannot determine the length of the iterables(s), so the length must be provided as an argument."
+                )
         if size is not None and (number is not None or ratio is not None):
             if number is None:
                 number = int(cpu_count * ratio)
@@ -54,12 +121,17 @@ class Chunks(Iterable):
         self.iterators = [iter(arg) for arg in iterables]
         self.number_of_items = length
         self.length = min(length, number)
-        self.lengths = [((i + 1) * self.number_of_items // self.length) - (i * self.number_of_items // self.length)
-                        for i in range(self.length)]
+        self.lengths = [
+            ((i + 1) * self.number_of_items // self.length) - (i * self.number_of_items // self.length)
+            for i in range(self.length)
+        ]
 
     def __iter__(self) -> Iterator[Any]:
         for i in range(self.length):
-            p, q = (i * self.number_of_items // self.length), ((i + 1) * self.number_of_items // self.length)
+            p, q = (
+                (i * self.number_of_items // self.length),
+                ((i + 1) * self.number_of_items // self.length),
+            )
             if len(self.iterators) == 1:
                 yield [next(self.iterators[0]) for _ in range(q - p)]
             else:
@@ -70,7 +142,12 @@ class Chunks(Iterable):
 
 
 class ExternalBar(Iterable):
-    def __init__(self, iterable: Iterable = None, callback: Callable[[int], None] = None, total: int = 0) -> None:
+    def __init__(
+        self,
+        iterable: Iterable = None,
+        callback: Callable[[int], None] = None,
+        total: int = 0,
+    ) -> None:
         self.iterable = iterable
         self.callback = callback
         self.total = total
@@ -102,11 +179,242 @@ class ExternalBar(Iterable):
                 self.callback(n)
 
 
-def gmap(fun: Callable[[Any, ...], Any], iterable: Iterable[Any] = None,
-         args: tuple[Any, ...] = None, kwargs: dict[str, Any] = None, total: int = None, desc: str = None,
-         bar: Bar | bool = True, terminator: Callable[[], None] = None, serial: bool = None, length: int = None,
-         n_processes: int = None, yield_ordered: bool = True, yield_index: bool = False,
-         **bar_kwargs: Any) -> Generator[Any, None, None]:
+@ray.remote
+def worker(task):
+    try:
+        with (
+            warnings.catch_warnings(),
+            redirect_stdout(open(os.devnull, "w")),
+            redirect_stderr(open(os.devnull, "w")),
+        ):
+            warnings.simplefilter("ignore", category=FutureWarning)
+            try:
+                task()
+                task.status = "done",
+            except Exception:  # noqa
+                task.status = "task_error", format_exc()
+    except KeyboardInterrupt:  # noqa
+        pass
+
+    return task
+
+
+class Task:
+    def __init__(
+        self,
+        handle: Hashable,
+        fun: Callable[[Any, ...], Any],
+        args: tuple[Any, ...] = (),
+        kwargs: dict[str, Any] = None,
+    ) -> None:
+        self.handle = handle
+        self.fun = fun
+        self.args = args
+        self.kwargs = kwargs
+        self.name = fun.__name__ if hasattr(fun, "__name__") else None
+        self.done = False
+        self.result = None
+        self.future = None
+        self.status = "starting"
+
+    @property
+    def fun(self) -> Callable[[Any, ...], Any]:
+        return ray.get(self._fun)
+
+    @fun.setter
+    def fun(self, fun: Callable[[Any, ...], Any]):
+        self._fun = ray.put(fun)
+
+    @property
+    def args(self) -> tuple[Any, ...]:
+        return tuple([ray.get(arg) for arg in self._args])
+
+    @args.setter
+    def args(self, args: tuple[Any, ...]) -> None:
+        self._args = [ray.put(arg) for arg in args]
+
+    @property
+    def kwargs(self) -> dict[str, Any]:
+        return {key: ray.get(value) for key, value in self._kwargs.items()}
+
+    @kwargs.setter
+    def kwargs(self, kwargs: dict[str, Any]) -> None:
+        self._kwargs = {key: ray.put(value) for key, value in kwargs.items()}
+
+    @property
+    def result(self) -> Any:
+        return ray.get(self._result)
+
+    @result.setter
+    def result(self, result: Any) -> None:
+        self._result = ray.put(result)
+
+    def __call__(self) -> Task:
+        if not self.done:
+            self.result = self.fun(*self.args, **self.kwargs)  # noqa
+            self.done = True
+        return self
+
+    def __repr__(self) -> str:
+        if self.done:
+            return f"Task {self.handle}, result: {self.result}"
+        else:
+            return f"Task {self.handle}"
+
+
+class ParPool:
+    """Parallel processing with addition of iterations at any time and request of that result any time after that.
+    The target function and its argument can be changed at any time.
+    """
+
+    def __init__(
+        self,
+        fun: Callable[[Any, ...], Any] = None,
+        args: tuple[Any] = None,
+        kwargs: dict[str, Any] = None,
+        n_processes: int = None,
+        bar: Bar = None,
+    ):
+        self.handle = 0
+        self.tasks = {}
+        self.bar = bar
+        self.bar_lengths = {}
+        self.fun = fun
+        self.args = args
+        self.kwargs = kwargs
+        PoolSingleton(n_processes)
+
+    def __getstate__(self) -> NoReturn:
+        raise RuntimeError(f"Cannot pickle {self.__class__.__name__} object.")
+
+    def __enter__(self) -> ParPool:
+        return self
+
+    def __exit__(self, *args: Any, **kwargs: Any) -> None:
+        pass
+
+    def __call__(self, n: Any, handle: Hashable = None, barlength: int = 1) -> None:
+        self.add_task(
+            args=(n, *(() if self.args is None else self.args)),
+            handle=handle,
+            barlength=barlength,
+        )
+
+    def add_task(
+        self,
+        fun: Callable[[Any, ...], Any] = None,
+        args: tuple[Any, ...] = None,
+        kwargs: dict[str, Any] = None,
+        handle: Hashable = None,
+        barlength: int = 1,
+    ) -> Optional[int]:
+        if handle is None:
+            new_handle = self.handle
+            self.handle += 1
+        else:
+            new_handle = handle
+        if new_handle in self:
+            raise ValueError(f"handle {new_handle} already present")
+        task = Task(
+            new_handle,
+            fun or self.fun,
+            args or self.args,
+            kwargs or self.kwargs,
+        )
+        task.future = worker.remote(task)
+        self.tasks[new_handle] = task
+        self.bar_lengths[new_handle] = barlength
+        if handle is None:
+            return new_handle
+        else:
+            return None
+
+    def __setitem__(self, handle: Hashable, n: Any) -> None:
+        """Add new iteration."""
+        self(n, handle=handle)
+
+    def __getitem__(self, handle: Hashable) -> Any:
+        """Request result and delete its record. Wait if result not yet available."""
+        if handle not in self:
+            raise ValueError(f"No handle: {handle} in pool")
+        task = ray.get(self.tasks[handle].future)
+        return self.finalize_task(task)
+
+    def __contains__(self, handle: Hashable) -> bool:
+        return handle in self.tasks
+
+    def __delitem__(self, handle: Hashable) -> None:
+        self.tasks.pop(handle)
+
+    def finalize_task(self, task: Task) -> Any:
+        code, *args = task.status
+        getattr(self, code)(task, *args)
+        self.tasks.pop(task.handle)
+        return task.result
+
+    def get_newest(self) -> Optional[Any]:
+        """Request the newest handle and result and delete its record. Wait if result not yet available."""
+        while True:
+            for handle, task in self.tasks.items():
+                if handle in self.bar_lengths:
+                    try:
+                        task = ray.get(task.future, timeout=0.01)
+                        return task.handle, self.finalize_task(task)
+                    except ray.exceptions.GetTimeoutError:
+                        pass
+
+    def task_error(self, task: Task, error: Exception) -> None:
+        if task.handle in self:
+            task = self.tasks[task.handle]
+            print(f"Error from process working on iteration {task.handle}:\n")
+            print(error)
+            print("Retrying in main process...")
+            task()
+            raise Exception(f"Function '{task.name}' cannot be executed by parfor, amend or execute in serial.")
+
+    def done(self, task: Task) -> None:
+        if task.handle in self:  # if not, the task was restarted erroneously
+            self.tasks[task.handle] = task
+            if hasattr(self.bar, "update"):
+                self.bar.update(self.bar_lengths.pop(task.handle))
+
+
+class PoolSingleton:
+    instance: PoolSingleton = None
+    cpu_count: int = int(os.cpu_count())
+
+    def __new__(cls, n_processes: int = None, *args: Any, **kwargs: Any) -> PoolSingleton:
+        # restart if any workers have shut down or if we want to have a different number of processes
+        n_processes = n_processes or cls.cpu_count
+        if cls.instance is None or cls.instance.n_processes != n_processes:
+            cls.instance = super().__new__(cls)
+            cls.instance.n_processes = n_processes
+            if ray.is_initialized():
+                warnings.warn("not setting n_processes because parallel pool was already initialized")
+            else:
+                os.environ["RAY_ACCEL_ENV_VAR_OVERRIDE_ON_ZERO"] = "0"
+                ray.init(num_cpus=n_processes, logging_level=logging.ERROR, log_to_driver=False)
+        return cls.instance
+
+
+class Worker:
+    nested: bool = False
+
+
+def gmap(
+    fun: Callable[[Any, ...], Any],
+    iterable: Iterable[Any] = None,
+    args: tuple[Any, ...] = None,
+    kwargs: dict[str, Any] = None,
+    total: int = None,
+    desc: str = None,
+    bar: Bar | bool = True,
+    serial: bool = None,
+    n_processes: int = None,
+    yield_ordered: bool = True,
+    yield_index: bool = False,
+    **bar_kwargs: Any,
+) -> Generator[Any, None, None]:
     """map a function fun to each iteration in iterable
     use as a function: pmap
     use as a decorator: parfor
@@ -177,15 +485,6 @@ def gmap(fun: Callable[[Any, ...], Any], iterable: Iterable[Any] = None,
         fun
         >> [0, 3, 12, 27, 48, 75, 108, 147, 192, 243]
     """
-    if total is None and length is not None:
-        total = length
-        warn('parfor: use of \'length\' is deprecated, use \'total\' instead', DeprecationWarning, stacklevel=2)
-        warn('parfor: use of \'length\' is deprecated, use \'total\' instead', DeprecationWarning, stacklevel=3)
-    if terminator is not None:
-        warn('parfor: use of \'terminator\' is deprecated, workers are terminated automatically',
-             DeprecationWarning, stacklevel=2)
-        warn('parfor: use of \'terminator\' is deprecated, workers are terminated automatically',
-             DeprecationWarning, stacklevel=3)
     is_chunked = isinstance(iterable, Chunks)
     if is_chunked:
         chunk_fun = fun
@@ -201,13 +500,13 @@ def gmap(fun: Callable[[Any, ...], Any], iterable: Iterable[Any] = None,
     if kwargs is None:
         kwargs = {}
 
-    if 'total' not in bar_kwargs:
-        bar_kwargs['total'] = sum(iterable.lengths)
-    if 'desc' not in bar_kwargs:
-        bar_kwargs['desc'] = desc
-    if 'disable' not in bar_kwargs:
-        bar_kwargs['disable'] = not bar
-    if serial is True or (serial is None and len(iterable) < min(cpu_count, 4)) or Worker.nested:  # serial case
+    if "total" not in bar_kwargs:
+        bar_kwargs["total"] = sum(iterable.lengths)
+    if "desc" not in bar_kwargs:
+        bar_kwargs["desc"] = desc
+    if "disable" not in bar_kwargs:
+        bar_kwargs["disable"] = not bar
+    if serial is True or (serial is None and len(iterable) < min(cpu_count, 4)):  # serial case
 
         def tqdm_chunks(chunks: Chunks, *args, **kwargs) -> Iterable[Any]:  # noqa
             with tqdm(*args, **kwargs) as b:
@@ -215,8 +514,9 @@ def gmap(fun: Callable[[Any, ...], Any], iterable: Iterable[Any] = None,
                     yield chunk
                     b.update(length)
 
-        iterable = (ExternalBar(iterable, bar, sum(iterable.lengths)) if callable(bar)
-                    else tqdm_chunks(iterable, **bar_kwargs))
+        iterable = (
+            ExternalBar(iterable, bar, sum(iterable.lengths)) if callable(bar) else tqdm_chunks(iterable, **bar_kwargs)  # type: ignore
+        )
         if is_chunked:
             if yield_index:
                 for i, c in enumerate(iterable):
@@ -234,9 +534,9 @@ def gmap(fun: Callable[[Any, ...], Any], iterable: Iterable[Any] = None,
                     yield from chunk_fun(c, *args, **kwargs)
 
     else:  # parallel case
-        with ExitStack() as stack:
+        with ExitStack() as stack:  # noqa
             if callable(bar):
-                bar = stack.enter_context(ExternalBar(callback=bar))
+                bar = stack.enter_context(ExternalBar(callback=bar))  # noqa
             else:
                 bar = stack.enter_context(tqdm(**bar_kwargs))
             with ParPool(chunk_fun, args, kwargs, n_processes, bar) as p:  # type: ignore
@@ -287,12 +587,13 @@ def pmap(*args, **kwargs) -> list[Any]:
 def parfor(*args: Any, **kwargs: Any) -> Callable[[Callable[[Any, ...], Any]], list[Any]]:
     def decfun(fun: Callable[[Any, ...], Any]) -> list[Any]:
         return pmap(fun, *args, **kwargs)
+
     return decfun
 
 
 try:
     parfor.__doc__ = pmap.__doc__ = gmap.__doc__
     pmap.__annotations__ = gmap.__annotations__ | pmap.__annotations__
-    parfor.__annotations__ = {key: value for key, value in pmap.__annotations__.items() if key != 'fun'}
+    parfor.__annotations__ = {key: value for key, value in pmap.__annotations__.items() if key != "fun"}
 except AttributeError:
     pass

parfor/common.py

@@ -1,58 +0,0 @@
-from __future__ import annotations
-
-import os
-from multiprocessing.shared_memory import SharedMemory
-from typing import Any, Callable, Protocol, Sequence
-
-import numpy as np
-from numpy.typing import ArrayLike, DTypeLike
-
-cpu_count = int(os.cpu_count())
-
-
-class Bar(Protocol):
-    def update(self, n: int = 1) -> None: ...
-
-
-class SharedArray(np.ndarray):
-    """ Numpy array whose memory can be shared between processes, so that memory use is reduced and changes in one
-        process are reflected in all other processes. Changes are not atomic, so protect changes with a lock to prevent
-        race conditions!
-    """
-
-    def __new__(cls, shape: int | Sequence[int], dtype: DTypeLike = float, shm: str | SharedMemory = None,
-                offset: int = 0, strides: tuple[int, int] = None, order: str = None) -> SharedArray:
-        if isinstance(shm, str):
-            shm = SharedMemory(shm)
-        elif shm is None:
-            shm = SharedMemory(create=True, size=np.prod(shape) * np.dtype(dtype).itemsize)
-        new = super().__new__(cls, shape, dtype, shm.buf, offset, strides, order)
-        new.shm = shm
-        return new
-
-    def __reduce__(self) -> tuple[Callable[[int | Sequence[int], DTypeLike, str], SharedArray],
-                                  tuple[int | tuple[int, ...], np.dtype, str]]:
-        return self.__class__, (self.shape, self.dtype, self.shm.name)
-
-    def __enter__(self) -> SharedArray:
-        return self
-
-    def __exit__(self, *args: Any, **kwargs: Any) -> None:
-        if hasattr(self, 'shm'):
-            self.shm.close()
-            self.shm.unlink()
-
-    def __del__(self) -> None:
-        if hasattr(self, 'shm'):
-            self.shm.close()
-
-    def __array_finalize__(self, obj: np.ndarray | None) -> None:
-        if isinstance(obj, np.ndarray) and not isinstance(obj, SharedArray):
-            raise TypeError('view casting to SharedArray is not implemented because right now we need to make a copy')
-
-    @classmethod
-    def from_array(cls, array: ArrayLike) -> SharedArray:
-        """ copy existing array into a SharedArray """
-        new = cls(array.shape, array.dtype)
-        new[:] = array[:]
-        return new

parfor/gil.py

@@ -1,463 +0,0 @@
-from __future__ import annotations
-
-import asyncio
-import multiprocessing
-from collections import UserDict
-from contextlib import redirect_stderr, redirect_stdout
-from os import cpu_count, devnull, getpid
-from time import time
-from traceback import format_exc
-from typing import Any, Callable, Hashable, NoReturn, Optional
-from warnings import warn
-
-from .common import Bar
-from .pickler import dumps, loads
-
-
-class SharedMemory(UserDict):
-    def __init__(self, manager: multiprocessing.Manager) -> None:
-        super().__init__()
-        self.data = manager.dict()  # item_id: dilled representation of object
-        self.references = manager.dict()  # item_id: counter
-        self.references_lock = manager.Lock()
-        self.cache = {}  # item_id: object
-        self.trash_can = {}
-        self.pool_ids = {}  # item_id: {(pool_id, task_handle), ...}
-
-    def __getstate__(self) -> tuple[dict[int, bytes], dict[int, int], multiprocessing.Lock]:
-        return self.data, self.references, self.references_lock
-
-    def __setitem__(self, item_id: int, value: Any) -> None:
-        if item_id not in self:  # values will not be changed
-            try:
-                self.data[item_id] = False, value
-            except Exception:  # only use our pickler when necessary # noqa
-                self.data[item_id] = True, dumps(value, recurse=True)
-            with self.references_lock:
-                try:
-                    self.references[item_id] += 1
-                except KeyError:
-                    self.references[item_id] = 1
-            self.cache[item_id] = value  # the id of the object will not be reused as long as the object exists
-
-    def add_item(self, item: Any, pool_id: int, task_handle: Hashable) -> int:
-        item_id = id(item)
-        self[item_id] = item
-        if item_id in self.pool_ids:
-            self.pool_ids[item_id].add((pool_id, task_handle))
-        else:
-            self.pool_ids[item_id] = {(pool_id, task_handle)}
-        return item_id
-
-    def remove_pool(self, pool_id: int) -> None:
-        """ remove objects used by a pool that won't be needed anymore """
-        self.pool_ids = {key: v for key, value in self.pool_ids.items() if (v := {i for i in value if i[0] != pool_id})}
-        for item_id in set(self.data.keys()) - set(self.pool_ids):
-            del self[item_id]
-        self.garbage_collect()
-
-    def remove_task(self, pool_id: int, task: Task) -> None:
-        """ remove objects used by a task that won't be needed anymore """
-        self.pool_ids = {key: v for key, value in self.pool_ids.items() if (v := value - {(pool_id, task.handle)})}
-        for item_id in {task.fun, *task.args, *task.kwargs} - set(self.pool_ids):
-            del self[item_id]
-        self.garbage_collect()
-
-    # worker functions
-    def __setstate__(self, state: dict) -> None:
-        self.data, self.references, self.references_lock = state
-        self.cache = {}
-        self.trash_can = None
-
-    def __getitem__(self, item_id: int) -> Any:
-        if item_id not in self.cache:
-            dilled, value = self.data[item_id]
-            if dilled:
-                value = loads(value)
-            with self.references_lock:
-                if item_id in self.references:
-                    self.references[item_id] += 1
-                else:
-                    self.references[item_id] = 1
-            self.cache[item_id] = value
-        return self.cache[item_id]
-
-    def garbage_collect(self) -> None:
-        """ clean up the cache """
-        for item_id in set(self.cache) - set(self.data.keys()):
-            with self.references_lock:
-                try:
-                    self.references[item_id] -= 1
-                except KeyError:
-                    self.references[item_id] = 0
-            if self.trash_can is not None and item_id not in self.trash_can:
-                self.trash_can[item_id] = self.cache[item_id]
-            del self.cache[item_id]
-
-        if self.trash_can:
-            for item_id in set(self.trash_can):
-                if self.references[item_id] == 0:
-                    # make sure every process removed the object before removing it in the parent
-                    del self.references[item_id]
-                    del self.trash_can[item_id]
-
-
-class Task:
-    def __init__(self, shared_memory: SharedMemory, pool_id: int, handle: Hashable, fun: Callable[[Any, ...], Any],
-                 args: tuple[Any, ...] = (), kwargs: dict[str, Any] = None) -> None:
-        self.pool_id = pool_id
-        self.handle = handle
-        self.fun = shared_memory.add_item(fun, pool_id, handle)
-        self.args = [shared_memory.add_item(arg, pool_id, handle) for arg in args]
-        self.kwargs = [] if kwargs is None else [shared_memory.add_item(item, pool_id, handle)
-                                                 for item in kwargs.items()]
-        self.name = fun.__name__ if hasattr(fun, '__name__') else None
-        self.done = False
-        self.result = None
-        self.pid = None
-
-    def __getstate__(self) -> dict[str, Any]:
-        state = self.__dict__
-        if self.result is not None:
-            state['result'] = dumps(self.result, recurse=True)
-        return state
-
-    def __setstate__(self, state: dict[str, Any]) -> None:
-        self.__dict__.update({key: value for key, value in state.items() if key != 'result'})
-        if state['result'] is None:
-            self.result = None
-        else:
-            self.result = loads(state['result'])
-
-    def __call__(self, shared_memory: SharedMemory) -> Task:
-        if not self.done:
-            fun = shared_memory[self.fun] or (lambda *args, **kwargs: None)  # noqa
-            args = [shared_memory[arg] for arg in self.args]
-            kwargs = dict([shared_memory[kwarg] for kwarg in self.kwargs])
-            self.result = fun(*args, **kwargs)  # noqa
-            self.done = True
-        return self
-
-    def __repr__(self) -> str:
-        if self.done:
-            return f'Task {self.handle}, result: {self.result}'
-        else:
-            return f'Task {self.handle}'
-
-
-class Context(multiprocessing.context.SpawnContext):
-    """ Provide a context where child processes never are daemonic. """
-    class Process(multiprocessing.context.SpawnProcess):
-        @property
-        def daemon(self) -> bool:
-            return False
-
-        @daemon.setter
-        def daemon(self, value: bool) -> None:
-            pass
-
-
-class ParPool:
-    """ Parallel processing with addition of iterations at any time and request of that result any time after that.
-        The target function and its argument can be changed at any time.
-    """
-    def __init__(self, fun: Callable[[Any, ...], Any] = None,
-                 args: tuple[Any] = None, kwargs: dict[str, Any] = None, n_processes: int = None, bar: Bar = None):
-        self.id = id(self)
-        self.handle = 0
-        self.tasks = {}
-        self.bar = bar
-        self.bar_lengths = {}
-        self.spool = PoolSingleton(n_processes, self)
-        self.manager = self.spool.manager
-        self.fun = fun
-        self.args = args
-        self.kwargs = kwargs
-        self.is_started = False
-
-    def __getstate__(self) -> NoReturn:
-        raise RuntimeError(f'Cannot pickle {self.__class__.__name__} object.')
-
-    def __enter__(self) -> ParPool:
-        return self
-
-    def __exit__(self, *args: Any, **kwargs: Any) -> None:
-        self.close()
-
-    def close(self) -> None:
-        self.spool.remove_pool(self.id)
-
-    def __call__(self, n: Any, handle: Hashable = None, barlength: int = 1) -> None:
-        self.add_task(args=(n, *(() if self.args is None else self.args)), handle=handle, barlength=barlength)
-
-    def add_task(self, fun: Callable[[Any, ...], Any] = None, args: tuple[Any, ...] = None,
-                 kwargs: dict[str, Any] = None, handle: Hashable = None, barlength: int = 1) -> Optional[int]:
-        if self.id not in self.spool.pools:
-            raise ValueError(f'this pool is not registered (anymore) with the pool singleton')
-        if handle is None:
-            new_handle = self.handle
-            self.handle += 1
-        else:
-            new_handle = handle
-        if new_handle in self:
-            raise ValueError(f'handle {new_handle} already present')
-        task = Task(self.spool.shared_memory, self.id, new_handle,
-                    fun or self.fun, args or self.args, kwargs or self.kwargs)
-        self.tasks[new_handle] = task
-        self.spool.add_task(task)
-        self.bar_lengths[new_handle] = barlength
-        if handle is None:
-            return new_handle
-
-    def __setitem__(self, handle: Hashable, n: Any) -> None:
-        """ Add new iteration. """
-        self(n, handle=handle)
-
-    def __getitem__(self, handle: Hashable) -> Any:
-        """ Request result and delete its record. Wait if result not yet available. """
-        if handle not in self:
-            raise ValueError(f'No handle: {handle} in pool')
-        while not self.tasks[handle].done:
-            if not self.spool.get_from_queue() and not self.tasks[handle].done and self.is_started \
-                    and not self.working:
-                for _ in range(10):  # wait some time while processing possible new messages
-                    self.spool.get_from_queue()
-                if not self.spool.get_from_queue() and not self.tasks[handle].done and self.is_started \
-                        and not self.working:
-                    # retry a task if the process was killed while working on a task
-                    self.spool.add_task(self.tasks[handle])
-                    warn(f'Task {handle} was restarted because the process working on it was probably killed.')
-        result = self.tasks[handle].result
-        self.tasks.pop(handle)
-        return result
-
-    def __contains__(self, handle: Hashable) -> bool:
-        return handle in self.tasks
-
-    def __delitem__(self, handle: Hashable) -> None:
-        self.tasks.pop(handle)
-
-    def get_newest(self) -> Any:
-        return self.spool.get_newest_for_pool(self)
-
-    def process_queue(self) -> None:
-        self.spool.process_queue()
-
-    def task_error(self, handle: Hashable, error: Exception) -> None:
-        if handle in self:
-            task = self.tasks[handle]
-            print(f'Error from process working on iteration {handle}:\n')
-            print(error)
-            print('Retrying in main process...')
-            task(self.spool.shared_memory)
-            self.spool.shared_memory.remove_task(self.id, task)
-            raise Exception(f'Function \'{task.name}\' cannot be executed by parfor, amend or execute in serial.')
-
-    def done(self, task: Task) -> None:
-        if task.handle in self:  # if not, the task was restarted erroneously
-            self.tasks[task.handle] = task
-            if hasattr(self.bar, 'update'):
-                self.bar.update(self.bar_lengths.pop(task.handle))
-        self.spool.shared_memory.remove_task(self.id, task)
-
-    def started(self, handle: Hashable, pid: int) -> None:
-        self.is_started = True
-        if handle in self:  # if not, the task was restarted erroneously
-            self.tasks[handle].pid = pid
-
-    @property
-    def working(self) -> bool:
-        return not all([task.pid is None for task in self.tasks.values()])
-
-
-class PoolSingleton:
-    """ There can be only one pool at a time, but the pool can be restarted by calling close() and then constructing a
-        new pool. The pool will close itself after 10 minutes of idle time. """
-
-    instance = None
-    cpu_count = cpu_count()
-
-    def __new__(cls, n_processes: int = None, *args: Any, **kwargs: Any) -> PoolSingleton:
-        # restart if any workers have shut down or if we want to have a different number of processes
-        if cls.instance is not None:
-            if (cls.instance.n_workers.value < cls.instance.n_processes or
-                    cls.instance.n_processes != (n_processes or cls.cpu_count)):
-                cls.instance.close()
-        if cls.instance is None or not cls.instance.is_alive:
-            new = super().__new__(cls)
-            new.n_processes = n_processes or cls.cpu_count
-            new.instance = new
-            new.is_started = False
-            ctx = Context()
-            new.n_workers = ctx.Value('i', new.n_processes)
-            new.event = ctx.Event()
-            new.queue_in = ctx.Queue(3 * new.n_processes)
-            new.queue_out = ctx.Queue(new.n_processes)
-            new.manager = ctx.Manager()
-            new.shared_memory = SharedMemory(new.manager)
-            new.pool = ctx.Pool(new.n_processes,
-                                Worker(new.shared_memory, new.queue_in, new.queue_out, new.n_workers, new.event))
-            new.is_alive = True
-            new.handle = 0
-            new.pools = {}
-            new.time_out = None
-            cls.instance = new
-        return cls.instance
-
-    def __init__(self, n_processes: int = None, parpool: Parpool = None) -> None:  # noqa
-        if parpool is not None:
-            self.pools[parpool.id] = parpool
-            if self.time_out is not None:
-                self.time_out.cancel()
-            self.time_out = None
-
-    def __getstate__(self) -> NoReturn:
-        raise RuntimeError(f'Cannot pickle {self.__class__.__name__} object.')
-
-    def remove_pool(self, pool_id: int) -> None:
-        self.shared_memory.remove_pool(pool_id)
-        if pool_id in self.pools:
-            self.pools.pop(pool_id)
-        if len(self.pools) == 0:
-            try:
-                self.time_out = asyncio.get_running_loop().call_later(600, self.close)  # noqa
-            except RuntimeError:
-                self.time_out = asyncio.new_event_loop().call_later(600, self.close)  # noqa
-
-    def error(self, error: Exception) -> NoReturn:
-        self.close()
-        raise Exception(f'Error occurred in worker: {error}')
-
-    def process_queue(self) -> None:
-        while self.get_from_queue():
-            pass
-
-    def get_from_queue(self) -> bool:
-        """ Get an item from the queue and store it, return True if more messages are waiting. """
-        try:
-            code, pool_id, *args = self.queue_out.get(True, 0.02)
-            if pool_id is None:
-                getattr(self, code)(*args)
-            elif pool_id in self.pools:
-                getattr(self.pools[pool_id], code)(*args)
-            return True
-        except multiprocessing.queues.Empty:  # noqa
-            for pool in self.pools.values():
-                for handle, task in pool.tasks.items():  # retry a task if the process doing it was killed
-                    if task.pid is not None \
-                            and task.pid not in [child.pid for child in multiprocessing.active_children()]:
-                        self.queue_in.put(task)
-                        warn(f'Task {task.handle} was restarted because process {task.pid} was probably killed.')
-            return False
-
-    def add_task(self, task: Task) -> None:
-        """ Add new iteration, using optional manually defined handle."""
-        if self.is_alive and not self.event.is_set():
-            while self.queue_in.full():
-                self.get_from_queue()
-            self.queue_in.put(task)
-        self.shared_memory.garbage_collect()
-
-    def get_newest_for_pool(self, pool: ParPool) -> tuple[Hashable, Any]:
-        """ Request the newest key and result and delete its record. Wait if result not yet available. """
-        while len(pool.tasks):
-            self.get_from_queue()
-            for task in pool.tasks.values():
-                if task.done:
-                    handle, result = task.handle, task.result
-                    pool.tasks.pop(handle)
-                    return handle, result
-
-    @classmethod
-    def close(cls) -> None:
-        if cls.instance is not None:
-            instance = cls.instance
-            cls.instance = None
-            if instance.time_out is not None:
-                instance.time_out.cancel()
-
-            def empty_queue(queue):
-                try:
-                    if not queue._closed:  # noqa
-                        while not queue.empty():
-                            try:
-                                queue.get(True, 0.02)
-                            except multiprocessing.queues.Empty:  # noqa
-                                pass
-                except OSError:
-                    pass
-
-            def close_queue(queue: multiprocessing.queues.Queue) -> None:
-                empty_queue(queue)  # noqa
-                if not queue._closed:  # noqa
-                    queue.close()
-                queue.join_thread()
-
-            if instance.is_alive:
-                instance.is_alive = False
-                instance.event.set()
-                instance.pool.close()
-                t = time()
-                while instance.n_workers.value:
-                    empty_queue(instance.queue_in)
-                    empty_queue(instance.queue_out)
-                    if time() - t > 10:
-                        warn(f'Parfor: Closing pool timed out, {instance.n_workers.value} processes still alive.')
-                        instance.pool.terminate()
-                        break
-                empty_queue(instance.queue_in)
-                empty_queue(instance.queue_out)
-                instance.pool.join()
-                close_queue(instance.queue_in)
-                close_queue(instance.queue_out)
-                instance.manager.shutdown()
-                instance.handle = 0
-
-
-class Worker:
-    """ Manages executing the target function which will be executed in different processes. """
-    nested = False
-
-    def __init__(self, shared_memory: SharedMemory, queue_in: multiprocessing.queues.Queue,
-                 queue_out: multiprocessing.queues.Queue, n_workers: multiprocessing.Value,
-                 event: multiprocessing.Event) -> None:
-        self.shared_memory = shared_memory
-        self.queue_in = queue_in
-        self.queue_out = queue_out
-        self.n_workers = n_workers
-        self.event = event
-
-    def add_to_queue(self, *args: Any) -> None:
-        while not self.event.is_set():
-            try:
-                self.queue_out.put(args, timeout=0.1)
-                break
-            except multiprocessing.queues.Full:  # noqa
-                continue
-
-    def __call__(self) -> None:
-        Worker.nested = True
-        pid = getpid()
-        last_active_time = time()
-        while not self.event.is_set() and time() - last_active_time < 600:
-            try:
-                with redirect_stdout(open(devnull, 'w')), redirect_stderr(open(devnull, 'w')):
-                    task = self.queue_in.get(True, 0.02)
-                    try:
-                        self.add_to_queue('started', task.pool_id, task.handle, pid)
-                        self.add_to_queue('done', task.pool_id, task(self.shared_memory))
-                    except Exception:  # noqa
-                        self.add_to_queue('task_error', task.pool_id, task.handle, format_exc())
-                        self.event.set()
-                self.shared_memory.garbage_collect()
-                last_active_time = time()
-            except (multiprocessing.queues.Empty, KeyboardInterrupt):  # noqa
-                pass
-            except Exception:  # noqa
-                self.add_to_queue('error', None, format_exc())
-                self.event.set()
-                self.shared_memory.garbage_collect()
-        for child in multiprocessing.active_children():
-            child.kill()
-        with self.n_workers:
-            self.n_workers.value -= 1

parfor/nogil.py

@@ -1,158 +0,0 @@
-from __future__ import annotations
-
-import queue
-import threading
-from os import cpu_count
-from typing import Any, Callable, Hashable, NoReturn, Optional
-
-from .common import Bar
-
-
-class Worker:
-    nested = False
-
-    def __init__(self, *args, **kwargs):
-        pass
-
-
-class PoolSingleton:
-    cpu_count = cpu_count()
-
-    def __init__(self, *args, **kwargs):
-        pass
-
-    def close(self):
-        pass
-
-
-class Task:
-    def __init__(self, queue: queue.Queue, handle: Hashable, fun: Callable[[Any, ...], Any],  # noqa
-                 args: tuple[Any, ...] = (), kwargs: dict[str, Any] = None) -> None:
-        self.queue = queue
-        self.handle = handle
-        self.fun = fun
-        self.args = args
-        self.kwargs = {} if kwargs is None else kwargs
-        self.name = fun.__name__ if hasattr(fun, '__name__') else None
-        self.started = False
-        self.done = False
-        self.result = None
-
-    def __call__(self):
-        if not self.done:
-            self.result = self.fun(*self.args, **self.kwargs)
-            try:
-                self.queue.put(self.handle)
-            except queue.ShutDown:
-                pass
-
-    def __repr__(self) -> str:
-        if self.done:
-            return f'Task {self.handle}, result: {self.result}'
-        else:
-            return f'Task {self.handle}'
-
-
-class ParPool:
-    """ Parallel processing with addition of iterations at any time and request of that result any time after that.
-        The target function and its argument can be changed at any time.
-    """
-    def __init__(self, fun: Callable[[Any, ...], Any] = None,
-                 args: tuple[Any] = None, kwargs: dict[str, Any] = None, n_processes: int = None, bar: Bar = None):
-        self.queue = queue.Queue()
-        self.handle = 0
-        self.tasks = {}
-        self.bar = bar
-        self.bar_lengths = {}
-        self.fun = fun
-        self.args = args
-        self.kwargs = kwargs
-        self.n_processes = n_processes or PoolSingleton.cpu_count
-        self.threads = {}
-
-    def __getstate__(self) -> NoReturn:
-        raise RuntimeError(f'Cannot pickle {self.__class__.__name__} object.')
-
-    def __enter__(self) -> ParPool:
-        return self
-
-    def __exit__(self, *args: Any, **kwargs: Any) -> None:
-        self.close()
-
-    def close(self) -> None:
-        self.queue.shutdown()  # noqa python3.13
-        for thread in self.threads.values():
-            thread.join()
-
-    def __call__(self, n: Any, handle: Hashable = None, barlength: int = 1) -> None:
-        self.add_task(args=(n, *(() if self.args is None else self.args)), handle=handle, barlength=barlength)
-
-    def add_task(self, fun: Callable[[Any, ...], Any] = None, args: tuple[Any, ...] = None,
-                 kwargs: dict[str, Any] = None, handle: Hashable = None, barlength: int = 1) -> Optional[int]:
-        if handle is None:
-            new_handle = self.handle
-            self.handle += 1
-        else:
-            new_handle = handle
-        if new_handle in self:
-            raise ValueError(f'handle {new_handle} already present')
-        task = Task(self.queue, new_handle, fun or self.fun, args or self.args, kwargs or self.kwargs)
-        while len(self.threads) > self.n_processes:
-            self.get_from_queue()
-        thread = threading.Thread(target=task)
-        thread.start()
-        self.threads[new_handle] = thread
-        self.tasks[new_handle] = task
-        self.bar_lengths[new_handle] = barlength
-        if handle is None:
-            return new_handle
-
-    def __setitem__(self, handle: Hashable, n: Any) -> None:
-        """ Add new iteration. """
-        self(n, handle=handle)
-
-    def __getitem__(self, handle: Hashable) -> Any:
-        """ Request result and delete its record. Wait if result not yet available. """
-        if handle not in self:
-            raise ValueError(f'No handle: {handle} in pool')
-        while not self.tasks[handle].done:
-            self.get_from_queue()
-        task = self.tasks.pop(handle)
-        return task.result
-
-    def __contains__(self, handle: Hashable) -> bool:
-        return handle in self.tasks
-
-    def __delitem__(self, handle: Hashable) -> None:
-        self.tasks.pop(handle)
-
-    def get_from_queue(self) -> bool:
-        """ Get an item from the queue and store it, return True if more messages are waiting. """
-        try:
-            handle = self.queue.get(True, 0.02)
-            self.done(handle)
-            return True
-        except (queue.Empty, queue.ShutDown):
-            return False
-
-    def get_newest(self) -> Any:
-        """ Request the newest key and result and delete its record. Wait if result not yet available. """
-        while len(self.tasks):
-            self.get_from_queue()
-            for task in self.tasks.values():
-                if task.done:
-                    handle, result = task.handle, task.result
-                    self.tasks.pop(handle)
-                    return handle, result
-
-    def process_queue(self) -> None:
-        while self.get_from_queue():
-            pass
-
-    def done(self, handle: Hashable) -> None:
-        thread = self.threads.pop(handle)
-        thread.join()
-        task = self.tasks[handle]
-        task.done = True
-        if hasattr(self.bar, 'update'):
-            self.bar.update(self.bar_lengths.pop(handle))

parfor/pickler.py

@@ -1,119 +0,0 @@
-from __future__ import annotations
-
-import copyreg
-from io import BytesIO
-from pickle import PicklingError
-from typing import Any, Callable
-
-import dill
-
-loads = dill.loads
-
-
-class CouldNotBePickled:
-    def __init__(self, class_name: str) -> None:
-        self.class_name = class_name
-
-    def __repr__(self) -> str:
-        return f"Item of type '{self.class_name}' could not be pickled and was omitted."
-
-    @classmethod
-    def reduce(cls, item: Any) -> tuple[Callable[[str], CouldNotBePickled], tuple[str]]:
-        return cls, (type(item).__name__,)
-
-
-class Pickler(dill.Pickler):
-    """ Overload dill to ignore unpicklable parts of objects.
-        You probably didn't want to use these parts anyhow.
-        However, if you did, you'll have to find some way to make them picklable.
-    """
-    def save(self, obj: Any, save_persistent_id: bool = True) -> None:
-        """ Copied from pickle and amended. """
-        self.framer.commit_frame()
-
-        # Check for persistent id (defined by a subclass)
-        pid = self.persistent_id(obj)
-        if pid is not None and save_persistent_id:
-            self.save_pers(pid)
-            return
-
-        # Check the memo
-        x = self.memo.get(id(obj))
-        if x is not None:
-            self.write(self.get(x[0]))
-            return
-
-        rv = NotImplemented
-        reduce = getattr(self, "reducer_override", None)
-        if reduce is not None:
-            rv = reduce(obj)
-
-        if rv is NotImplemented:
-            # Check the type dispatch table
-            t = type(obj)
-            f = self.dispatch.get(t)
-            if f is not None:
-                f(self, obj)  # Call unbound method with explicit self
-                return
-
-            # Check private dispatch table if any, or else
-            # copyreg.dispatch_table
-            reduce = getattr(self, 'dispatch_table', copyreg.dispatch_table).get(t)
-            if reduce is not None:
-                rv = reduce(obj)
-            else:
-                # Check for a class with a custom metaclass; treat as regular
-                # class
-                if issubclass(t, type):
-                    self.save_global(obj)
-                    return
-
-                # Check for a __reduce_ex__ method, fall back to __reduce__
-                reduce = getattr(obj, "__reduce_ex__", None)
-                try:
-                    if reduce is not None:
-                        rv = reduce(self.proto)
-                    else:
-                        reduce = getattr(obj, "__reduce__", None)
-                        if reduce is not None:
-                            rv = reduce()
-                        else:
-                            raise PicklingError("Can't pickle %r object: %r" %
-                                                (t.__name__, obj))
-                except Exception:  # noqa
-                    rv = CouldNotBePickled.reduce(obj)
-
-        # Check for string returned by reduce(), meaning "save as global"
-        if isinstance(rv, str):
-            try:
-                self.save_global(obj, rv)
-            except Exception:  # noqa
-                self.save_global(obj, CouldNotBePickled.reduce(obj))
-            return
-
-        # Assert that reduce() returned a tuple
-        if not isinstance(rv, tuple):
-            raise PicklingError("%s must return string or tuple" % reduce)
-
-        # Assert that it returned an appropriately sized tuple
-        length = len(rv)
-        if not (2 <= length <= 6):
-            raise PicklingError("Tuple returned by %s must have "
-                                "two to six elements" % reduce)
-
-        # Save the reduce() output and finally memoize the object
-        try:
-            self.save_reduce(obj=obj, *rv)
-        except Exception:  # noqa
-            self.save_reduce(obj=obj, *CouldNotBePickled.reduce(obj))
-
-
-def dumps(obj: Any, protocol: str = None, byref: bool = None, fmode: str = None, recurse: bool = True,
-          **kwds: Any) -> bytes:
-    """pickle an object to a string"""
-    protocol = dill.settings['protocol'] if protocol is None else int(protocol)
-    _kwds = kwds.copy()
-    _kwds.update(dict(byref=byref, fmode=fmode, recurse=recurse))
-    with BytesIO() as file:
-        Pickler(file, protocol, **_kwds).dump(obj)
-        return file.getvalue()

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "parfor"
-version = "2025.1.0"
+version = "2026.1.0"
 description = "A package to mimic the use of parfor as done in Matlab."
 authors = ["Wim Pomp <wimpomp@gmail.com>"]
 license = "GPLv3"
@@ -17,6 +17,10 @@ pytest = { version = "*", optional = true }
 [tool.poetry.extras]
 test = ["pytest", "numpy"]
 
+[tool.ruff]
+line-length = 119
+indent-width = 4
+
 [tool.isort]
 line_length = 119
 

tests/test_parfor.py

@@ -1,9 +1,6 @@
 from __future__ import annotations
 
-import sys
 from dataclasses import dataclass
-from os import getpid
-from time import sleep
 from typing import Any, Iterator, Optional, Sequence
 
 import numpy as np
@@ -11,14 +8,6 @@ import pytest
 
 from parfor import Chunks, ParPool, SharedArray, parfor, pmap
 
-try:
-    if sys._is_gil_enabled():  # noqa
-        gil = True
-    else:
-        gil = False
-except Exception:  # noqa
-    gil = True
-
 
 class SequenceIterator:
     def __init__(self, sequence: Sequence) -> None:
@@ -56,7 +45,7 @@ def iterators() -> tuple[Iterator, Optional[int]]:
     yield Iterable(range(10)), 10
 
 
-@pytest.mark.parametrize('iterator', iterators())
+@pytest.mark.parametrize("iterator", iterators())
 def test_chunks(iterator: tuple[Iterator, Optional[int]]) -> None:
     chunks = Chunks(iterator[0], size=2, length=iterator[1])
     assert list(chunks) == [[0, 1], [2, 3], [4, 5], [6, 7], [8, 9]]
@@ -66,7 +55,7 @@ def test_parpool() -> None:
     def fun(i, j, k) -> int:  # noqa
         return i * j * k
 
-    with ParPool(fun, (3,), {'k': 2}) as pool:  # noqa
+    with ParPool(fun, (3,), {"k": 2}) as pool:  # noqa
         for i in range(10):
             pool[i] = i
 
@@ -74,40 +63,66 @@ def test_parpool() -> None:
 
 
 def test_parfor() -> None:
-    @parfor(range(10), (3,), {'k': 2})
+    @parfor(range(10), (3,), {"k": 2})
     def fun(i, j, k):
         return i * j * k
 
     assert fun == [0, 6, 12, 18, 24, 30, 36, 42, 48, 54]
 
 
-@pytest.mark.parametrize('serial', (True, False))
+@pytest.mark.parametrize("serial", (True, False))
 def test_pmap(serial) -> None:
     def fun(i, j, k):
         return i * j * k
 
-    assert pmap(fun, range(10), (3,), {'k': 2}, serial=serial) == [0, 6, 12, 18, 24, 30, 36, 42, 48, 54]
+    assert pmap(fun, range(10), (3,), {"k": 2}, serial=serial) == [
+        0,
+        6,
+        12,
+        18,
+        24,
+        30,
+        36,
+        42,
+        48,
+        54,
+    ]
 
 
-@pytest.mark.parametrize('serial', (True, False))
+@pytest.mark.parametrize("serial", (True, False))
 def test_pmap_with_idx(serial) -> None:
     def fun(i, j, k):
         return i * j * k
 
-    assert (pmap(fun, range(10), (3,), {'k': 2}, serial=serial, yield_index=True) ==
-            [(0, 0), (1, 6), (2, 12), (3, 18), (4, 24), (5, 30), (6, 36), (7, 42), (8, 48), (9, 54)])
+    assert pmap(fun, range(10), (3,), {"k": 2}, serial=serial, yield_index=True) == [
+        (0, 0),
+        (1, 6),
+        (2, 12),
+        (3, 18),
+        (4, 24),
+        (5, 30),
+        (6, 36),
+        (7, 42),
+        (8, 48),
+        (9, 54),
+    ]
 
 
-@pytest.mark.parametrize('serial', (True, False))
+@pytest.mark.parametrize("serial", (True, False))
 def test_pmap_chunks(serial) -> None:
     def fun(i, j, k):
         return [i_ * j * k for i_ in i]
 
     chunks = Chunks(range(10), size=2)
-    assert pmap(fun, chunks, (3,), {'k': 2}, serial=serial) == [[0, 6], [12, 18], [24, 30], [36, 42], [48, 54]]
+    assert pmap(fun, chunks, (3,), {"k": 2}, serial=serial) == [
+        [0, 6],
+        [12, 18],
+        [24, 30],
+        [36, 42],
+        [48, 54],
+    ]
 
 
-@pytest.mark.skipif(not gil, reason='test if gil enabled only')
 def test_id_reuse() -> None:
     def fun(i):
         return i[0].a
@@ -126,18 +141,6 @@ def test_id_reuse() -> None:
     assert all([i == j for i, j in enumerate(a)])
 
 
-@pytest.mark.skipif(not gil, reason='test if gil enabled only')
-@pytest.mark.parametrize('n_processes', (2, 4, 6))
-def test_n_processes(n_processes) -> None:
-
-    @parfor(range(12), n_processes=n_processes)
-    def fun(i):  # noqa
-        sleep(0.25)
-        return getpid()
-
-    assert len(set(fun)) == n_processes
-
-
 def test_shared_array() -> None:
     def fun(i, a):
         a[i] = i