Adding parametric compilation for QVM and QPU (#39)

* Fixes the plugin to support pyquil 2.16

* bump pyQuil version

* added rewiring

* Fixed qubit measuring order

* store compiled program

* remove partial rewiring

* return partial

* fix wiring key error

* First draft of porting to QubitDevice

* Modifying BasisState such that it uses the wires passed (instead of enumerate); rename CCNOT to Toffoli; fix test for test_qvm

* Fixing qvm and qpu and their tests

* Fixes for the wavelength simulator and tests

* Fixing WavefunctionDevice and NumpyWaveFunction Device; added functionality to raise an error for QVM analytic=True case (test included)

* Increasing shots for QPU tests

* Modifying comments, removing active_wires from test

* Update pennylane_forest/qpu.py

Co-Authored-By: Josh Izaac <josh146@gmail.com>

* Implementing feedback

* Docstring

* First draft

* Using keyword arguments for apply, fixing matrices that were used previously from default.qubit, increasing number of shots such that the stochastic tests will more likely pass

* Adding the lookup table, unit tests and a WIP integration test

* First draft of lookup table and parametric compilation (tests to be modified)

* Modifying the requirements file for the checks

* Making the parameter dictionaries instance attributes, such that there are no conflicts between devices

* Decreasing number of shots and adding flaky tests to stochastic test cases (each is tried 10 times and they need to pass at least once)

* Rename apply_wiring to remap_wires

* Adding timeouts that can be defined for qvms, adding tests

* Adding timeouts that can be defined for qpus, adding tests

* Adding tests for the mutable QNode cases

* Docstrings

* Tweak tests

* Remove no longer used instance attribute _eigs from QVMDevice

* Moving the compilation specific changes to to QVMDevice (as no other ForestDevice would have the concept implemented); restricting the QPU lattices in the qvm and qpu tests such that only 5 qubit devices are chosen; adding tests for coverage (e.g. BasisState not used as first)

* Move Variable attribute init to test

* Docstrings and refactor to apply_rotations

* Refactor QVMDevice such that generate_samples returns samples instead of returning and assigning it to dev._samples; adjusting the tests accordingly

* Docstrings to attributes and apply_rotations method

* Adding comments to parametric compilation logic

* Moving comments before if statements, renaming lookup_table

* Remove unused imports

* Modfying qpu test to be a parametrized test

* Adjust flaky runs

* Add comment to test

* Correct previous error

* Remove parameter_map and parameter_reference_map attributes from ForestDevice -> fixing the resulting failing tests by defining reset method in QVMDevice containing a resetting of these attributes; adding compiled_program property (and underlying attribute) which contains the latest compiled program (regardless of whether parametric compilation is turned on or off); refactor generate_samples and place comments inside; adding parametrized tests; adding tests for compiled_program

* Modify timeout for test where server failed to respond

* Timeout

* Update pennylane_forest/qpu.py

Co-Authored-By: Josh Izaac <josh146@gmail.com>

* Update pennylane_forest/qpu.py

Co-Authored-By: Josh Izaac <josh146@gmail.com>

* Update pennylane_forest/qpu.py

Co-Authored-By: Josh Izaac <josh146@gmail.com>

* Docstrings

* Reverting pennylane version requirement in requirements.txt

* Blacking

* Reverting requirements modification; version can be incremented upon release

Co-authored-by: Josh Izaac <josh146@gmail.com>

doc/conf.py

@@ -18,41 +18,41 @@
 # If extensions (or modules to document with autodoc) are in another directory,
 # add these directories to sys.path here. If the directory is relative to the
 # documentation root, use os.path.abspath to make it absolute, like shown here.
-sys.path.insert(0, os.path.abspath('..'))
-sys.path.insert(0, os.path.abspath('_ext'))
+sys.path.insert(0, os.path.abspath(".."))
+sys.path.insert(0, os.path.abspath("_ext"))
 
 # -- General configuration ------------------------------------------------
 
 # If your documentation needs a minimal Sphinx version, state it here.
-needs_sphinx = '1.6'
+needs_sphinx = "1.6"
 
 # Add any Sphinx extension module names here, as strings. They can be
 # extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
 # ones.
 extensions = [
-    'sphinx.ext.autodoc',
-    'sphinx.ext.autosummary',
-    'sphinx.ext.todo',
-    'sphinx.ext.coverage',
-    'sphinx.ext.mathjax',
-    'sphinx.ext.napoleon',
-    'sphinx.ext.inheritance_diagram',
-    'sphinx.ext.viewcode',
+    "sphinx.ext.autodoc",
+    "sphinx.ext.autosummary",
+    "sphinx.ext.todo",
+    "sphinx.ext.coverage",
+    "sphinx.ext.mathjax",
+    "sphinx.ext.napoleon",
+    "sphinx.ext.inheritance_diagram",
+    "sphinx.ext.viewcode",
 ]
 
 # The suffix(es) of source filenames.
 # You can specify multiple suffix as a list of string:
 #
 # source_suffix = ['.rst', '.md']
-source_suffix = '.rst'
+source_suffix = ".rst"
 
 # The master toctree document.
-master_doc = 'index'
+master_doc = "index"
 
 # General information about the project.
-project = 'PennyLane-Forest'
+project = "PennyLane-Forest"
 copyright = "Copyright 2018."
-author = 'Xanadu and Rigetti Computing.'
+author = "Xanadu and Rigetti Computing."
 
 add_module_names = False
 
@@ -61,11 +61,12 @@
 # built documents.
 
 import pennylane_forest
+
 # The full version, including alpha/beta/rc tags.
 release = pennylane_forest.__version__
 
 # The short X.Y version.
-version = re.match(r'^(\d+\.\d+)', release).expand(r'\1')
+version = re.match(r"^(\d+\.\d+)", release).expand(r"\1")
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.
@@ -75,19 +76,19 @@
 language = None
 
 # today_fmt is used as the format for a strftime call.
-today_fmt = '%Y-%m-%d'
+today_fmt = "%Y-%m-%d"
 
 # List of patterns, relative to source directory, that match files and
 # directories to ignore when looking for source files.
 # This patterns also effect to html_static_path and html_extra_path
-exclude_patterns = ['_build', 'Thumbs.db', '.DS_Store']
+exclude_patterns = ["_build", "Thumbs.db", ".DS_Store"]
 
 # If true, sectionauthor and moduleauthor directives will be shown in the
 # output. They are ignored by default.
 show_authors = True
 
 # The name of the Pygments (syntax highlighting) style to use.
-pygments_style = 'sphinx'
+pygments_style = "sphinx"
 
 # If true, `todo` and `todoList` produce output, else they produce nothing.
 todo_include_todos = True
@@ -103,21 +104,21 @@
 # Theme options are theme-specific and customize the look and feel of a theme
 # further.  For a list of options available for each theme, see the
 # documentation.
-#html_theme_options = {}
+# html_theme_options = {}
 
 # Add any paths that contain custom themes here, relative to this directory.
-#html_theme_path = []
+# html_theme_path = []
 
 # The name for this set of Sphinx documents.  If None, it defaults to
 # "<project> v<release> documentation".
-#html_title = None
+# html_title = None
 
 # A shorter title for the navigation bar.  Default is the same as html_title.
-#html_short_title = None
+# html_short_title = None
 
 # The name of an image file (relative to this directory) to place at the top
 # of the sidebar.
-#html_logo = None
+# html_logo = None
 
 # The name of an image file (relative to this directory) to use as a favicon of
 # the docs.  This file should be a Windows icon file (.ico) being 16x16 or 32x32
@@ -132,90 +133,90 @@
 # Add any extra paths that contain custom files (such as robots.txt or
 # .htaccess) here, relative to this directory. These files are copied
 # directly to the root of the documentation.
-#html_extra_path = []
+# html_extra_path = []
 
 # If not '', a 'Last updated on:' timestamp is inserted at every page bottom,
 # using the given strftime format.
-#html_last_updated_fmt = '%b %d, %Y'
+# html_last_updated_fmt = '%b %d, %Y'
 
 # If true, SmartyPants will be used to convert quotes and dashes to
 # typographically correct entities.
-#html_use_smartypants = True
+# html_use_smartypants = True
 
 # Custom sidebar templates, must be a dictionary that maps document names
 # to template names.
 #
 # This is required for the alabaster theme
 # refs: http://alabaster.readthedocs.io/en/latest/installation.html#sidebars
-#html_sidebars = {
+# html_sidebars = {
 #    '**': [
 #        'about.html',
 #        'navigation.html',
 #        'relations.html',  # needs 'show_related': True theme option to display
 #        'searchbox.html',
 #        'donate.html',
 #    ]
-#}
+# }
 html_sidebars = {
-    '**' : [
-        'logo-text.html',
-        'searchbox.html',
-        'globaltoc.html',
+    "**": [
+        "logo-text.html",
+        "searchbox.html",
+        "globaltoc.html",
         # 'sourcelink.html'
     ]
 }
 
 # Additional templates that should be rendered to pages, maps page names to
 # template names.
-#html_additional_pages = {}
+# html_additional_pages = {}
 
 # If false, no module index is generated.
-#html_domain_indices = True
+# html_domain_indices = True
 
 # If false, no index is generated.
-#html_use_index = True
+# html_use_index = True
 
 # If true, the index is split into individual pages for each letter.
-#html_split_index = False
+# html_split_index = False
 
 # If true, links to the reST sources are added to the pages.
-#html_show_sourcelink = True
+# html_show_sourcelink = True
 
 # If true, "Created using Sphinx" is shown in the HTML footer. Default is True.
-#html_show_sphinx = True
+# html_show_sphinx = True
 
 # If true, "(C) Copyright ..." is shown in the HTML footer. Default is True.
-#html_show_copyright = True
+# html_show_copyright = True
 
 # If true, an OpenSearch description file will be output, and all pages will
 # contain a <link> tag referring to it.  The value of this option must be the
 # base URL from which the finished HTML is served.
-#html_use_opensearch = ''
+# html_use_opensearch = ''
 
 # This is the file name suffix for HTML files (e.g. ".xhtml").
-#html_file_suffix = None
+# html_file_suffix = None
 
 # Language to be used for generating the HTML full-text search index.
 # Sphinx supports the following languages:
 #   'da', 'de', 'en', 'es', 'fi', 'fr', 'h', 'it', 'ja'
 #   'nl', 'no', 'pt', 'ro', 'r', 'sv', 'tr'
-#html_search_language = 'en'
+# html_search_language = 'en'
 
 # A dictionary with options for the search language support, empty by default.
 # Now only 'ja' uses this config value
-#html_search_options = {'type': 'default'}
+# html_search_options = {'type': 'default'}
 
 # The name of a javascript file (relative to the configuration directory) that
 # implements a search results scorer. If empty, the default will be used.
-#html_search_scorer = 'scorer.js'
+# html_search_scorer = 'scorer.js'
 
 # Output file base name for HTML help builder.
-htmlhelp_basename = 'PennyLaneForestdoc'
+htmlhelp_basename = "PennyLaneForestdoc"
 
 # -- Options for HTMLHelp output ------------------------------------------
 
 # Output file base name for HTML help builder.
-htmlhelp_basename = 'PennyLaneForestdoc'
+htmlhelp_basename = "PennyLaneForestdoc"
 
 
 # -- Options for LaTeX output ---------------------------------------------
@@ -224,39 +225,32 @@
     # The paper size ('letterpaper' or 'a4paper').
     #
     # 'papersize': 'letterpaper',
-
     # The font size ('10pt', '11pt' or '12pt').
     #
     # 'pointsize': '10pt',
-
     # Additional stuff for the LaTeX preamble.
     #
     # 'preamble': '',
-
     # Latex figure (float) alignment
     #
     # 'figure_align': 'htbp',
 }
 
-latex_additional_files = ['macros.tex']
+latex_additional_files = ["macros.tex"]
 
 # Grouping the document tree into LaTeX files. List of tuples
 # (source start file, target name, title,
 #  author, documentclass [howto, manual, or own class]).
 latex_documents = [
-    (master_doc, 'PennyLane-Forest.tex', 'PennyLane-Forest Documentation',
-     'Xanadu Inc.', 'manual'),
+    (master_doc, "PennyLane-Forest.tex", "PennyLane-Forest Documentation", "Xanadu Inc.", "manual")
 ]
 
 
 # -- Options for manual page output ---------------------------------------
 
 # One entry per manual page. List of tuples
 # (source start file, name, description, authors, manual section).
-man_pages = [
-    (master_doc, 'pennylane-forest', 'PennyLane-Forest Documentation',
-     [author], 1)
-]
+man_pages = [(master_doc, "pennylane-forest", "PennyLane-Forest Documentation", [author], 1)]
 
 
 # -- Options for Texinfo output -------------------------------------------
@@ -265,13 +259,19 @@
 # (source start file, target name, title, author,
 #  dir menu entry, description, category)
 texinfo_documents = [
-    (master_doc, 'PennyLane-Forest', 'PennyLane-Forest Documentation',
-     author, 'PennyLane-Forest', 'pyQuil plugin for the PennyLane quantum machine learning library.',
-     'Miscellaneous'),
+    (
+        master_doc,
+        "PennyLane-Forest",
+        "PennyLane-Forest Documentation",
+        author,
+        "PennyLane-Forest",
+        "pyQuil plugin for the PennyLane quantum machine learning library.",
+        "Miscellaneous",
+    )
 ]
 
 
-#============================================================
+# ============================================================
 
 # the order in which autodoc lists the documented members
-autodoc_member_order = 'bysource'
+autodoc_member_order = "bysource"

pennylane_forest/device.py

@@ -30,7 +30,6 @@
 ~~~~~~~~~~~~
 """
 import uuid
-import abc
 
 import numpy as np
 
@@ -44,7 +43,7 @@
 # following gates are not supported by PennyLane
 from pyquil.gates import S, T, CPHASE00, CPHASE01, CPHASE10, CPHASE, CCNOT, CSWAP, ISWAP, PSWAP
 
-from pennylane import QubitDevice
+from pennylane import QubitDevice, DeviceError
 
 from ._version import __version__
 
@@ -186,7 +185,7 @@ class ForestDevice(QubitDevice):
     _operation_map = pyquil_operation_map
     _capabilities = {"model": "qubit", "tensor_observables": True}
 
-    def __init__(self, wires, shots=1000, analytic=False,  **kwargs):
+    def __init__(self, wires, shots=1000, analytic=False, **kwargs):
         super().__init__(wires, shots, analytic=analytic)
         self.analytic = analytic
         self.forest_url = kwargs.get("forest_url", pyquil_config.forest_url)
@@ -244,21 +243,38 @@ def apply(self, operations, **kwargs):
 
         # Apply the circuit operations
         for i, operation in enumerate(operations):
-            # number of wires on device
+            # map the operation wires to the physical device qubits
             wires = self.remap_wires(operation.wires)
             par = operation.parameters
 
             if i > 0 and operation.name in ("QubitStateVector", "BasisState"):
-                raise DeviceError("Operation {} cannot be used after other Operations have already been applied "
-                                  "on a {} device.".format(operation.name, self.short_name))
-
+                raise DeviceError(
+                    "Operation {} cannot be used after other Operations have already "
+                    "been applied on a {} device.".format(operation.name, self.short_name)
+                )
             self.prog += self._operation_map[operation.name](*par, *wires)
 
-        # Apply the circuit rotations
+        self.prog += self.apply_rotations(rotations)
+
+    def apply_rotations(self, rotations):
+        """Apply the circuit rotations.
+
+        This method serves as an auxiliary method to :meth:`~.ForestDevice.apply`.
+
+        Args:
+            rotations (List[pennylane.Operation]): operations that rotate into the
+                measurement basis
+
+        Returns:
+            pyquil.Program: the pyquil Program that specifies the corresponding rotations
+        """
+        rotation_operations = Program()
         for operation in rotations:
             wires = self.remap_wires(operation.wires)
             par = operation.parameters
-            self.prog += self._operation_map[operation.name](*par, *wires)
+            rotation_operations += self._operation_map[operation.name](*par, *wires)
+
+        return rotation_operations
 
     def reset(self):
         self.prog = Program()