Deprecate qiskit.tools (#11514)

* Deprecate qiskit.tools

This commit deprecates the qiskit.tools module. Most of the
functionality in this module will be removed in the Qiskit 1.0.0
release. The sole exception is the qiskit.tools.parallel module and it's
associated public function qiskit.tools.parallel_map which has been
moved to qiskit.utils.

* Fix lint

* Fix lint

* test/python/circuit/test_parameters.py

* Adjust import path

* Add context around QuTiP origins of parallel_map

---------

Co-authored-by: Luciano Bello <bel@zurich.ibm.com>

qiskit/passmanager/passmanager.py

@@ -21,7 +21,7 @@
 
 import dill
 
-from qiskit.tools.parallel import parallel_map
+from qiskit.utils.parallel import parallel_map
 from .base_tasks import Task, PassManagerIR
 from .exceptions import PassManagerError
 from .flow_controllers import FlowControllerLinear

qiskit/test/base.py

@@ -28,7 +28,7 @@
 import unittest
 from unittest.util import safe_repr
 
-from qiskit.tools.parallel import get_platform_parallel_default
+from qiskit.utils.parallel import get_platform_parallel_default
 from qiskit.utils import optionals as _optionals
 from qiskit.circuit import QuantumCircuit
 from .decorators import enforce_subclasses_call

qiskit/tools/__init__.py

@@ -17,15 +17,6 @@
 
 .. currentmodule:: qiskit.tools
 
-Parallel Routines
------------------
-
-A helper function for calling a custom function with python ``ProcessPoolExecutor``.
-Tasks can be executed in parallel using this function.
-It has a built-in event publisher to show the progress of the parallel tasks.
-
-.. autofunction:: parallel_map
-
 Monitoring
 ----------
 
@@ -38,7 +29,34 @@
 .. automodule:: qiskit.tools.events
 
 """
-
-from .parallel import parallel_map
-from .monitor import job_monitor, backend_monitor, backend_overview
-from .events import progressbar
+import importlib
+import warnings
+
+
+_DEPRECATED_NAMES = {
+    "parallel_map": "qiskit.utils",
+    "parallel": "qiskit.utils.parallel",
+}
+
+
+_DEPRECATED_REMOVALS = {"job_monitor", "backend_monitor", "backend_overview", "progressbar"}
+
+
+def __getattr__(name):
+    if name in _DEPRECATED_NAMES:
+        module_name = _DEPRECATED_NAMES[name]
+        warnings.warn(
+            f"Accessing '{name}' from '{__name__}' is deprecated since Qiskit 0.46.0 "
+            f"and will be removed in Qiskit 1.0.0. Import from '{module_name}' instead ",
+            DeprecationWarning,
+            2,
+        )
+        return getattr(importlib.import_module(module_name), name)
+    if name in _DEPRECATED_REMOVALS:
+        warnings.warn(
+            f"'{name}' has been deprecated and will be removed in Qiskit 1.0.0.",
+            DeprecationWarning,
+            2,
+        )
+        return getattr(importlib.import_module(".monitor", "qiskit.tools"), name)
+    raise AttributeError(f"module '{__name__}' has no attribute '{name}'")

qiskit/tools/events/__init__.py

@@ -21,5 +21,10 @@
 
 .. autoclass:: TextProgressBar
 """
+import warnings
 
 from .progressbar import TextProgressBar
+
+warnings.warn(
+    "qiskit.tools.events is deprecated and will be removed in Qiskit 1.0.0", DeprecationWarning, 2
+)

qiskit/tools/events/progressbar.py

@@ -48,7 +48,7 @@
 import time
 import datetime
 import sys
-from qiskit.tools.events.pubsub import Subscriber
+from .pubsub import Subscriber
 
 
 class BaseProgressBar(Subscriber):

qiskit/tools/jupyter/__init__.py

@@ -109,6 +109,10 @@
 from .monospace import MonospacedOutput
 from .job_watcher import JobWatcher, JobWatcherMagic
 
+warnings.warn(
+    "qiskit.tools.jupyter is deprecated and will be removed in Qiskit 1.0.0", DeprecationWarning, 2
+)
+
 _IP = get_ipython()
 if _IP is not None:
     _IP.register_magics(ProgressBarMagic)

qiskit/tools/monitor/__init__.py

@@ -12,5 +12,12 @@
 
 """A module for monitoring jobs, backends, etc."""
 
+import warnings
+
 from .job_monitor import job_monitor
 from .overview import backend_monitor, backend_overview
+
+
+warnings.warn(
+    "qiskit.tools.monitor is deprecated and will be removed in Qiskit 1.0.0", DeprecationWarning, 2
+)

qiskit/tools/parallel.py

@@ -1,6 +1,6 @@
 # This code is part of Qiskit.
 #
-# (C) Copyright IBM 2017, 2018.
+# (C) Copyright IBM 2017, 2019.
 #
 # This code is licensed under the Apache License, Version 2.0. You may
 # obtain a copy of this license in the LICENSE.txt file in the root directory
@@ -10,189 +10,14 @@
 # copyright notice, and modified files need to carry a notice indicating
 # that they have been altered from the originals.
 
-# This file is part of QuTiP: Quantum Toolbox in Python.
-#
-#    Copyright (c) 2011 and later, Paul D. Nation and Robert J. Johansson.
-#    All rights reserved.
-#
-#    Redistribution and use in source and binary forms, with or without
-#    modification, are permitted provided that the following conditions are
-#    met:
-#
-#    1. Redistributions of source code must retain the above copyright notice,
-#       this list of conditions and the following disclaimer.
-#
-#    2. Redistributions in binary form must reproduce the above copyright
-#       notice, this list of conditions and the following disclaimer in the
-#       documentation and/or other materials provided with the distribution.
-#
-#    3. Neither the name of the QuTiP: Quantum Toolbox in Python nor the names
-#       of its contributors may be used to endorse or promote products derived
-#       from this software without specific prior written permission.
-#
-#    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-#    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-#    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
-#    PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-#    HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-#    SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-#    LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-#    DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-#    THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-#    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-#    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-###############################################################################
-
-"""
-Routines for running Python functions in parallel using process pools
-from the multiprocessing library.
-"""
-
-import os
-from concurrent.futures import ProcessPoolExecutor
-import sys
-
-from qiskit.exceptions import QiskitError
-from qiskit.utils.multiprocessing import local_hardware_info
-from qiskit.tools.events.pubsub import Publisher
-from qiskit import user_config
-
-
-def get_platform_parallel_default():
-    """
-    Returns the default parallelism flag value for the current platform.
-
-    Returns:
-        parallel_default: The default parallelism flag value for the
-        current platform.
-
-    """
-    # Default False on Windows
-    if sys.platform == "win32":
-        parallel_default = False
-    # On macOS default false on Python >=3.8
-    elif sys.platform == "darwin":
-        parallel_default = False
-    # On linux (and other OSes) default to True
-    else:
-        parallel_default = True
-
-    return parallel_default
-
-
-CONFIG = user_config.get_config()
-
-if os.getenv("QISKIT_PARALLEL", None) is not None:
-    PARALLEL_DEFAULT = os.getenv("QISKIT_PARALLEL", None).lower() == "true"
-else:
-    PARALLEL_DEFAULT = get_platform_parallel_default()
-
-# Set parallel flag
-if os.getenv("QISKIT_IN_PARALLEL") is None:
-    os.environ["QISKIT_IN_PARALLEL"] = "FALSE"
-
-if os.getenv("QISKIT_NUM_PROCS") is not None:
-    CPU_COUNT = int(os.getenv("QISKIT_NUM_PROCS"))
-else:
-    CPU_COUNT = CONFIG.get("num_process", local_hardware_info()["cpus"])
-
-
-def _task_wrapper(param):
-    (task, value, task_args, task_kwargs) = param
-    return task(value, *task_args, **task_kwargs)
-
-
-def parallel_map(  # pylint: disable=dangerous-default-value
-    task, values, task_args=(), task_kwargs={}, num_processes=CPU_COUNT
-):
-    """
-    Parallel execution of a mapping of `values` to the function `task`. This
-    is functionally equivalent to::
-
-        result = [task(value, *task_args, **task_kwargs) for value in values]
-
-    On Windows this function defaults to a serial implementation to avoid the
-    overhead from spawning processes in Windows.
-
-    Args:
-        task (func): Function that is to be called for each value in ``values``.
-        values (array_like): List or array of values for which the ``task``
-                            function is to be evaluated.
-        task_args (list): Optional additional arguments to the ``task`` function.
-        task_kwargs (dict): Optional additional keyword argument to the ``task`` function.
-        num_processes (int): Number of processes to spawn.
-
-    Returns:
-        result: The result list contains the value of
-                ``task(value, *task_args, **task_kwargs)`` for
-                    each value in ``values``.
-
-    Raises:
-        QiskitError: If user interrupts via keyboard.
-
-    Events:
-        terra.parallel.start: The collection of parallel tasks are about to start.
-        terra.parallel.update: One of the parallel task has finished.
-        terra.parallel.finish: All the parallel tasks have finished.
-
-    Examples:
-
-        .. code-block:: python
-
-            import time
-            from qiskit.tools.parallel import parallel_map
-            def func(_):
-                    time.sleep(0.1)
-                    return 0
-            parallel_map(func, list(range(10)));
-    """
-    if len(values) == 0:
-        return []
-    if len(values) == 1:
-        return [task(values[0], *task_args, **task_kwargs)]
-
-    Publisher().publish("terra.parallel.start", len(values))
-    nfinished = [0]
-
-    def _callback(_):
-        nfinished[0] += 1
-        Publisher().publish("terra.parallel.done", nfinished[0])
-
-    # Run in parallel if not Win and not in parallel already
-    if (
-        num_processes > 1
-        and os.getenv("QISKIT_IN_PARALLEL") == "FALSE"
-        and CONFIG.get("parallel_enabled", PARALLEL_DEFAULT)
-    ):
-        os.environ["QISKIT_IN_PARALLEL"] = "TRUE"
-        try:
-            results = []
-            with ProcessPoolExecutor(max_workers=num_processes) as executor:
-                param = ((task, value, task_args, task_kwargs) for value in values)
-                future = executor.map(_task_wrapper, param)
-
-            results = list(future)
-            Publisher().publish("terra.parallel.done", len(results))
-
-        except (KeyboardInterrupt, Exception) as error:
-            if isinstance(error, KeyboardInterrupt):
-                Publisher().publish("terra.parallel.finish")
-                os.environ["QISKIT_IN_PARALLEL"] = "FALSE"
-                raise QiskitError("Keyboard interrupt in parallel_map.") from error
-            # Otherwise just reset parallel flag and error
-            os.environ["QISKIT_IN_PARALLEL"] = "FALSE"
-            raise error
+# pylint: disable=unused-wildcard-import,missing-module-docstring,wildcard-import
+import warnings
 
-        Publisher().publish("terra.parallel.finish")
-        os.environ["QISKIT_IN_PARALLEL"] = "FALSE"
-        return results
+from qiskit.utils.parallel import *
 
-    # Cannot do parallel on Windows , if another parallel_map is running in parallel,
-    # or len(values) == 1.
-    results = []
-    for _, value in enumerate(values):
-        result = task(value, *task_args, **task_kwargs)
-        results.append(result)
-        _callback(0)
-    Publisher().publish("terra.parallel.finish")
-    return results
+warnings.warn(
+    "'qiskit.tools.parallel' is deprecated and is now located at 'qiskit.utils.parallel'. This "
+    "path will no longer work in Qiskit 1.0.0",
+    DeprecationWarning,
+    2,
+)

qiskit/transpiler/passes/layout/sabre_layout.py

@@ -43,7 +43,7 @@
 from qiskit.transpiler.passes.routing.sabre_swap import _build_sabre_dag, _apply_sabre_result
 from qiskit.transpiler.target import Target
 from qiskit.transpiler.coupling import CouplingMap
-from qiskit.tools.parallel import CPU_COUNT
+from qiskit.utils.parallel import CPU_COUNT
 
 logger = logging.getLogger(__name__)
 

qiskit/utils/__init__.py

@@ -52,6 +52,15 @@
 are run on a device or simulator by passing a QuantumInstance setup with the desired
 backend etc.
 
+Parallel Routines
+-----------------
+A helper function for calling a custom function with python
+``ProcessPoolExecutor``. Tasks can be executed in parallel using this function.
+It has a built-in event publisher to show the progress of the parallel
+tasks.
+
+.. autofunction:: parallel_map
+
 
 Optional Dependency Checkers (:mod:`qiskit.utils.optionals`)
 ============================================================
@@ -81,6 +90,8 @@
 from .name_unnamed_args import name_args
 from .algorithm_globals import algorithm_globals
 
+from .parallel import parallel_map
+
 
 __all__ = [
     "LazyDependencyManager",
@@ -102,4 +113,5 @@
     "local_hardware_info",
     "is_main_process",
     "apply_prefix",
+    "parallel_map",
 ]

qiskit/utils/mitigation/_filters.py

@@ -29,7 +29,6 @@
 
 import qiskit
 from qiskit import QiskitError
-from qiskit.tools import parallel_map
 from qiskit.utils.mitigation.circuits import count_keys
 from qiskit.utils.deprecation import deprecate_func
 
@@ -112,6 +111,7 @@ def apply(self, raw_data, method="least_squares"):
         """
         from scipy.optimize import minimize
         from scipy import linalg as la
+        from qiskit.utils.parallel import parallel_map  # pylint: disable=cyclic-import
 
         # check forms of raw_data
         if isinstance(raw_data, dict):
@@ -365,6 +365,7 @@ def apply(
         """
         from scipy.optimize import minimize
         from scipy import linalg as la
+        from .. import parallel_map  # pylint: disable=cyclic-import
 
         all_states = count_keys(self.nqubits)
         num_of_states = 2**self.nqubits