Release 0.12.1

.clang-format

@@ -0,0 +1,3 @@
+BasedOnStyle: LLVM
+AlwaysBreakTemplateDeclarations: Yes
+RemoveBracesLLVM: No

.git-blame-ignore-revs

@@ -0,0 +1 @@
+8c9cfb3a2cde607dd0fe3236cc5ea53e6d06b2fe

.github/workflows/docs-publish.yml

@@ -1,5 +1,6 @@
 name: Docs Publish
 on:
+  workflow_dispatch:
   push:
     tags:
       - "*"

.github/workflows/docs.yml

@@ -37,7 +37,7 @@ jobs:
           pip install -U pip virtualenv wheel
           pip install -U tox
           sudo apt-get update
-          sudo apt-get install -y build-essential libopenblas-dev
+          sudo apt-get install -y build-essential libopenblas-dev pandoc
         shell: bash
       - name: Run Docs Build
         run: tox -edocs
@@ -50,7 +50,7 @@ jobs:
     needs: [docs]
     strategy:
       matrix:
-        python-version: [3.7]
+        python-version: [3.8]
     steps:
       - uses: actions/checkout@v2
       - name: Set up Python ${{ matrix.python-version }}

.github/workflows/tests.yml

@@ -34,10 +34,15 @@ jobs:
           pip install -U pip wheel
           pip install -U -c constraints.txt -r requirements-dev.txt qiskit-terra numpy scipy
         shell: bash
+      - name: Run clang-format
+        run: |
+          set -e
+          sh tools/clang-format.sh --Werror -n
+        shell: bash          
       - name: Run Lint
         run: |
           set -e
-          pycodestyle --ignore=E402,W503,W504 --max-line-length=100 qiskit_aer
+          black --check qiskit_aer test tools setup.py
           pylint -j 2 -rn qiskit_aer
   sdist:
     runs-on: ${{ matrix.platform.os }}

.pylintrc

@@ -21,7 +21,7 @@ persistent=yes
 # List of plugins (as comma separated values of python modules names) to load,
 # usually to register additional checkers.
 load-plugins=pylint.extensions.docparams, # enable checking of docstring args
-    pylint.extensions.docstyle  # basic docstring stle checks
+    pylint.extensions.docstyle,  # basic docstring style checks
 
 # Use multiple processes to speed up Pylint.
 jobs=1
@@ -33,8 +33,7 @@ unsafe-load-any-extension=no
 # A comma-separated list of package or module names from where C extensions may
 # be loaded. Extensions are loading into the active Python interpreter and may
 # run arbitrary code
-extension-pkg-whitelist=
-
+extension-pkg-allow-list=
 
 [MESSAGES CONTROL]
 
@@ -43,10 +42,10 @@ extension-pkg-whitelist=
 confidence=
 
 # Enable the message, report, category or checker with the given id(s). You can
-# either give multiple identifiers separated by comma (,) or put this option
+# either give multiple identifier separated by comma (,) or put this option
 # multiple time (only on the command line, not in the configuration file where
 # it should appear only once). See also the "--disable" option for examples.
-#enable=
+enable=use-symbolic-message-instead
 
 # Disable the message, report, category or checker with the given id(s). You
 # can either give multiple identifiers separated by comma (,) or put this
@@ -57,7 +56,8 @@ confidence=
 # --enable=similarities". If you want to run only the classes checker, but have
 # no Warning level messages displayed, use"--disable=all --enable=classes
 # --disable=W"
-disable=no-self-use,        # disabled as it is too verbose
+disable=spelling,       # way too noisy
+    no-self-use,        # disabled as it is too verbose
     fixme,              # disabled as TODOs would show up as warnings
     protected-access,   # disabled as we don't follow the public vs private
                         # convention strictly
@@ -70,8 +70,13 @@ disable=no-self-use,        # disabled as it is too verbose
     unnecessary-pass,   # allow for methods with just "pass", for clarity
     no-else-return,     # relax "elif" after a clause with a return
     docstring-first-line-empty, # relax docstring style
-    unsubscriptable-object, # pylint can't determine this for numpy types
-    bad-continuation, bad-whitespace # differences of opinion with black
+    import-outside-toplevel,
+    bad-continuation, bad-whitespace, # differences of opinion with black
+    import-error,       # overzealous with our optionals/dynamic packages
+    consider-using-f-string, # pass re-lint old commits
+    broad-exception-raised, # pass re-lint old commits
+    unsubscriptable-object # pass re-lint old commits
+
 
 
 
@@ -83,12 +88,6 @@ disable=no-self-use,        # disabled as it is too verbose
 # mypackage.mymodule.MyReporterClass.
 output-format=text
 
-# Put messages in a separate file for each module / package specified on the
-# command line instead of printing them on stdout. Reports (if any) will be
-# written in a file name "pylint_global.[txt|html]". This option is deprecated
-# and it will be removed in Pylint 2.0.
-files-output=no
-
 # Tells whether to display a full report or only the messages
 reports=yes
 
@@ -117,8 +116,8 @@ evaluation=10.0 - ((float(5 * error + warning + refactor + convention) / stateme
 # pi = the PI constant
 # op = operation iterator
 # b = basis iterator
-good-names=i,j,k,n,m,ex,v,w,x,y,z,Run,_,logger,q,c,r,qr,cr,qc,nd,pi,op,b,ar,br,dt,
-    __unittest
+good-names=a,b,i,j,k,d,n,m,ex,v,w,x,y,z,Run,_,logger,q,c,r,qr,cr,qc,nd,pi,op,b,ar,br,p,cp,dt,
+    __unittest,iSwapGate,mu
 
 # Bad variable names which should always be refused, separated by a comma
 bad-names=foo,bar,toto,tutu,tata
@@ -171,16 +170,16 @@ attr-rgx=[a-z_][a-z0-9_]{2,30}$
 attr-name-hint=[a-z_][a-z0-9_]{2,30}$
 
 # Regular expression matching correct argument names
-argument-rgx=[a-z_][a-z0-9_]{2,30}$
+argument-rgx=[a-z_][a-z0-9_]{2,30}|ax|dt$
 
 # Naming hint for argument names
 argument-name-hint=[a-z_][a-z0-9_]{2,30}$
 
 # Regular expression matching correct variable names
-variable-rgx=[a-z_][a-z0-9_]{2,30}$
+variable-rgx=[a-z_][a-z0-9_]{1,30}$
 
 # Naming hint for variable names
-variable-name-hint=[a-z_][a-z0-9_]{2,30}$
+variable-name-hint=[a-z_][a-z0-9_]{1,30}$
 
 # Regular expression matching correct class attribute names
 class-attribute-rgx=([A-Za-z_][A-Za-z0-9_]{2,30}|(__.*__))$
@@ -212,7 +211,7 @@ max-nested-blocks=5
 [FORMAT]
 
 # Maximum number of characters on a single line.
-max-line-length=100
+max-line-length=105
 
 # Regexp for a line that is allowed to be longer than the limit.
 ignore-long-lines=^\s*(# )?<?https?://\S+>?$
@@ -279,7 +278,7 @@ spelling-dict=
 spelling-ignore-words=
 
 # A path to a file that contains private dictionary; one word per line.
-spelling-private-dict-file=
+spelling-private-dict-file=.local-spellings
 
 # Tells whether to store unknown words to indicated private dictionary in
 # --spelling-private-dict-file option instead of raising a message.
@@ -296,7 +295,7 @@ ignore-mixin-members=yes
 # (useful for modules/projects where namespaces are manipulated during runtime
 # and thus existing member attributes cannot be deduced by static analysis. It
 # supports qualified module names, as well as Unix pattern matching.
-ignored-modules=matplotlib.cm,numpy.random,qiskit.providers
+ignored-modules=numpy
 
 # List of class names for which member attributes should not be checked (useful
 # for classes with dynamically set attributes). This supports the use of
@@ -333,7 +332,7 @@ callbacks=cb_,_cb
 
 # List of qualified module names which can have objects that can redefine
 # builtins.
-redefining-builtins-modules=six.moves,future.builtins,tools.compiler
+redefining-builtins-modules=six.moves,future.builtins
 
 
 [CLASSES]

CMakeLists.txt

@@ -262,7 +262,7 @@ if(AER_THRUST_SUPPORTED)
 		set(CUDA_NVCC_FLAGS "${CUDA_NVCC_FLAGS} ${AER_CUDA_ARCH_FLAGS_EXPAND} -DAER_THRUST_CUDA -I${AER_SIMULATOR_CPP_SRC_DIR} -isystem ${AER_SIMULATOR_CPP_SRC_DIR}/third-party/headers -use_fast_math --expt-extended-lambda")
 
 		set(AER_COMPILER_DEFINITIONS ${AER_COMPILER_DEFINITIONS} THRUST_DEVICE_SYSTEM=THRUST_DEVICE_SYSTEM_CUDA)
-		set(THRUST_DEPENDENT_LIBS "")
+		set(THRUST_DEPENDANT_LIBS "-L${CUDA_TOOLKIT_ROOT_DIR}/lib64")
 		if(NOT DEFINED CUQUANTUM_ROOT)
 			if(DEFINED ENV{CUQUANTUM_ROOT})
 				set(CUQUANTUM_ROOT $ENV{CUQUANTUM_ROOT})
@@ -283,14 +283,14 @@ if(AER_THRUST_SUPPORTED)
 			set(AER_COMPILER_DEFINITIONS ${AER_COMPILER_DEFINITIONS} AER_CUSTATEVEC AER_CUTENSORNET)
 			if(DEFINED CUQUANTUM_ROOT)
 				set(AER_COMPILER_FLAGS "${AER_COMPILER_FLAGS} -I${CUQUANTUM_ROOT}/include")
-				set(THRUST_DEPENDANT_LIBS "-L${CUQUANTUM_ROOT}/lib")
+				set(THRUST_DEPENDANT_LIBS "${THRUST_DEPENDANT_LIBS} -L${CUQUANTUM_ROOT}/lib/${CUDA_VERSION_MAJOR}")
 			endif()
 			if(DEFINED CUTENSOR_ROOT)
 				set(AER_COMPILER_FLAGS "${AER_COMPILER_FLAGS} -I${CUTENSOR_ROOT}/include")
-				set(THRUST_DEPENDANT_LIBS "${THRUST_DEPENDANT_LIBS} -L${CUTENSOR_ROOT}/lib/11")
+				set(THRUST_DEPENDANT_LIBS "${THRUST_DEPENDANT_LIBS} -L${CUTENSOR_ROOT}/lib/${CUDA_VERSION_MAJOR}")
 			endif()
             if(CUQUANTUM_STATIC)
-				set(THRUST_DEPENDANT_LIBS "${THRUST_DEPENDANT_LIBS} -lcustatevec_static -lcutensornet_static  -lcutensor -lcublas")
+				set(THRUST_DEPENDANT_LIBS "${THRUST_DEPENDANT_LIBS} -lcustatevec_static -lcutensornet_static  -lcutensor_static -lmetis_static -lcusolver_static -lcusparse_static -lcusolver_lapack_static -lcublas_static -lcublasLt_static -lculibos")
 			else()
 				set(THRUST_DEPENDANT_LIBS "${THRUST_DEPENDANT_LIBS} -lcustatevec -lcutensornet -lcutensor")
 			endif()
@@ -299,9 +299,9 @@ if(AER_THRUST_SUPPORTED)
 			set(AER_COMPILER_DEFINITIONS ${AER_COMPILER_DEFINITIONS} AER_CUSTATEVEC)
 			set(AER_COMPILER_FLAGS "${AER_COMPILER_FLAGS} -I${CUSTATEVEC_ROOT}/include")
             if(CUSTATEVEC_STATIC)
-				set(THRUST_DEPENDANT_LIBS "-L${CUSTATEVEC_ROOT}/lib -L${CUSTATEVEC_ROOT}/lib64 -lcustatevec_static -L${CUDA_TOOLKIT_ROOT_DIR}/lib64 -lcublas")
+				set(THRUST_DEPENDANT_LIBS "${THRUST_DEPENDANT_LIBS} -L${CUSTATEVEC_ROOT}/lib -L${CUSTATEVEC_ROOT}/lib/${CUDA_VERSION_MAJOR} -lcustatevec_static -lcusolver_static -lcusparse_static -lcusolver_lapack_static -lcublas_static -lcublasLt_static -lculibos")
 			else()
-				set(THRUST_DEPENDANT_LIBS "-L${CUSTATEVEC_ROOT}/lib -L${CUSTATEVEC_ROOT}/lib64 -lcustatevec")
+				set(THRUST_DEPENDANT_LIBS "${THRUST_DEPENDANT_LIBS} -L${CUSTATEVEC_ROOT}/lib -L${CUSTATEVEC_ROOT}/lib/${CUDA_VERSION_MAJOR} -lcustatevec")
 			endif()
 		endif()
 	elseif(AER_THRUST_BACKEND STREQUAL "TBB")

CONTRIBUTING.md

@@ -18,6 +18,11 @@ please ensure that:
 1. The code follows the code style of the project and successfully
    passes the tests. For convenience, you can execute `tox` locally,
    which will run these checks and report any issues.
+
+   If your code fails the local style checks, you can use `tox -eblack`
+   and `tox -eclang` to automatically fix and update the code formatting
+   in python and C++, respectively.
+
 2. The documentation has been updated accordingly. In particular, if a
    function or class has been modified during the PR, please update the
    *docstring* accordingly.
@@ -34,7 +39,7 @@ automation. This works through a combination of the git log and the pull
 request. When a release is tagged and pushed to GitHub, the release automation
 bot looks at all commit messages from the git log for the release. It takes the
 PR numbers from the git log (assuming a squash merge) and checks if that PR had
-a `Changelog:` label on it. If there is a label it will add the git commit
+a `Changelog:` label on it. If there is a label, it will add the git commit
 message summary line from the git log for the release to the changelog.
 
 If there are multiple `Changelog:` tags on a PR, the git commit message summary
@@ -64,7 +69,7 @@ understand if they need to update their program which uses Qiskit, and how they
 would go about doing that. It ideally should explain why they need to make
 this change too, to provide the necessary context.
 
-To make sure we don't forget a release note or if the details of user-facing
+To make sure we don't forget a release note if the details of user-facing
 changes over a release cycle, we require that all user facing changes include
 documentation at the same time as the code. To accomplish this, we use the
 [reno](https://docs.openstack.org/reno/latest/) tool which enables a git-based
@@ -181,10 +186,29 @@ https://github.com/Qiskit/qiskit/blob/master/docs/release_notes.rst)
 
 Building The release notes are part of the standard qiskit-aer documentation
 builds. To check what the rendered HTML output of the release notes will look
-like for the current state of the repo, you can run: `tox -edocs` which will
+like for the current state of the repo, you need to install 
+[pandoc](https://pandoc.org/installing.html), then you can run: `tox -edocs` which will
 build all the documentation into `docs/_build/html` and the release notes in
 particular will be located at `docs/_build/html/release_notes.html`
 
+## Style and lint
+
+Qiskit Aer uses 3 tools for verifying code formatting and lint checking. The
+first tool is [black](https://github.com/psf/black) which is a Python code formatting
+tool that will automatically update the code formatting to a consistent style.
+The second tool is [pylint](https://www.pylint.org/) which is a code linter
+which does a deeper analysis of the Python code to find both style issues and
+potential bugs and other common issues in Python. The third tool is
+[clang-format](https://clang.llvm.org/docs/ClangFormat.html) which is a
+C++ code formatting tool that will automatically update codes with a consistent style.
+
+You can check that your local modifications conform to the style rules
+by running `tox -elint` which will run `black`, `pylint` and `clang-format`
+to check the local code formatting and lint. If black returns a code
+formatting error you can run `tox -eblack` to automatically update the
+code formatting to conform to the style. However, if `pylint` returns
+any error you will have to fix these issues by manually updating your code.
+
 ### Development Cycle
 
 The development cycle for qiskit-aer is all handled in the open using
@@ -216,7 +240,7 @@ When it is time to release a new minor version of qiskit-aer, we will:
 1.  Create a new tag with the version number and push it to github
 2.  Change the `main` version to the next release version.
 
-The release automation processes will be triggered by the new tag and perform
+The release automation processes will be triggered by the new tag and will perform
 the following steps:
 
 1.  Create a stable branch for the new minor version from the release tag
@@ -439,7 +463,7 @@ As any other Python package, we can install from source code by just running:
     qiskit-aer$ pip install .
 
 This will build and install `Aer` with the default options which is probably suitable for most of the users.
-There's another Pythonic approach to build and install software: build the wheels distributable file.
+There's another Pythonic approach to building and installing software: build the wheels distributable file.
 
 
     qiskit-aer$ python ./setup.py bdist_wheel
@@ -542,7 +566,7 @@ As any other Python package, we can install from source code by just running:
     (QiskitDevEnv) qiskit-aer > pip install .
 
 This will build and install `Aer` with the default options which is probably suitable for most of the users.
-There's another Pythonic approach to build and install software: build the wheels distributable file.
+There's another Pythonic approach to building and installing software: build the wheels distributable file.
 
 
     (QiskitDevEnv) qiskit-aer > python ./setup.py bdist_wheel
@@ -1079,3 +1103,28 @@ Now we can run the Python interpreter and pass the arguments (the python file to
     Target 0: (python) stopped.
 
 After this, you can step through the code and continue with your debug session as always.
+
+
+## Dealing with the git blame ignore list
+
+In the qiskit-aer repository we maintain a list of commits for git blame to
+ignore. This is mostly commits that are code style changes that don't change
+the functionality but just change the code formatting (for example, when we
+migrated to use black for code formatting). This file, `.git-blame-ignore-revs`
+just contains a list of commit SHA1s you can tell git to ignore when using the
+`git blame` command. This can be done one time with something like
+
+```
+git blame --ignore-revs-file .git-blame-ignore-revs qiskit/version.py
+
+```
+
+from the root of the repository. If you'd like to enable this by default you
+can update your local repository's configuration with:
+
+```
+git config blame.ignoreRevsFile .git-blame-ignore-revs
+```
+
+which will update your local repositories configuration to use the ignore list
+by default.

README.md

@@ -4,7 +4,7 @@
 
 **Qiskit** is an open-source framework for working with noisy quantum computers at the level of pulses, circuits, and algorithms.
 
-Qiskit is made up of elements that each work together to enable quantum computing. This element is **Aer**, which provides high-performance quantum computing simulators with realistic noise models.
+Qiskit is made up of elements that work together to enable quantum computing. This element is **Aer**, which provides high-performance quantum computing simulators with realistic noise models.
 
 ## Installation
 
@@ -14,7 +14,7 @@ We encourage installing Qiskit via the pip tool (a python package manager). The
 pip install qiskit qiskit-aer
 ```
 
-Pip will handle all dependencies automatically for us and you will always install the latest (and well-tested) version.
+Pip will handle all dependencies automatically for us, and you will always install the latest (and well-tested) version.
 
 To install from source, follow the instructions in the [contribution guidelines](CONTRIBUTING.md).
 
@@ -34,7 +34,7 @@ the same functionality found in the canonical `qiskit-aer` package, plus the
 ability to run the GPU supported simulators: statevector, density matrix, and unitary.
 
 **Note**: This package is only available on x86_64 Linux. For other platforms
-that have CUDA support you will have to build from source. You can refer to
+that have CUDA support, you will have to build from source. You can refer to
 the [contributing guide](CONTRIBUTING.md#building-with-gpu-support)
 for instructions on doing this.
 
@@ -84,9 +84,9 @@ print('Counts(noise):', counts_noise)
 ## Contribution Guidelines
 
 If you'd like to contribute to Qiskit, please take a look at our
-[contribution guidelines](CONTRIBUTING.md). This project adheres to Qiskit's [code of conduct](CODE_OF_CONDUCT.md). By participating, you are expect to uphold to this code.
+[contribution guidelines](CONTRIBUTING.md). This project adheres to Qiskit's [code of conduct](CODE_OF_CONDUCT.md). By participating, you are expected to uphold this code.
 
-We use [GitHub issues](https://github.com/Qiskit/qiskit-aer/issues) for tracking requests and bugs. Please use our [slack](https://qiskit.slack.com) for discussion and simple questions. To join our Slack community use the [link](https://qiskit.slack.com/join/shared_invite/zt-fybmq791-hYRopcSH6YetxycNPXgv~A#/). For questions that are more suited for a forum we use the Qiskit tag in the [Stack Exchange](https://quantumcomputing.stackexchange.com/questions/tagged/qiskit).
+We use [GitHub issues](https://github.com/Qiskit/qiskit-aer/issues) for tracking requests and bugs. Please use our [slack](https://qiskit.slack.com) for discussion and simple questions. To join our Slack community use the [link](https://qiskit.slack.com/join/shared_invite/zt-fybmq791-hYRopcSH6YetxycNPXgv~A#/). For questions that are more suited for a forum, we use the Qiskit tag in the [Stack Exchange](https://quantumcomputing.stackexchange.com/questions/tagged/qiskit).
 
 ## Next Steps
 

cmake/FindPybind11.cmake

@@ -1,4 +1,4 @@
-find_package(PythonLibs REQUIRED)
+find_package(PythonLibs)
 
 message(STATUS ${PYTHON_INCLUDE_DIRS})
 message(STATUS "PYTHON EXECUTABLE: ${PYTHON_EXECUTABLE}")