Merge 322d80b into c7de986

Author: trbromley

.github/workflows/build.yml

@@ -17,7 +17,7 @@ jobs:
       - uses: actions/checkout@v2
 
       - name: Install dependencies
-        run: sudo apt-get -y -q install cmake gcc libeigen3-dev
+        run: sudo apt-get -y -q install cmake gcc
 
       - name: Install Google Test
         run: |
@@ -50,7 +50,7 @@ jobs:
           python-version: '3.7'
 
       - name: Install dependencies
-        run: sudo apt-get -y -q install cmake gcc libeigen3-dev
+        run: sudo apt-get -y -q install cmake gcc
 
       - name: Get required Python packages
         run: |

.github/workflows/deploy.yml

@@ -6,27 +6,11 @@ on:
 env:
   CIBW_SKIP: "cp27-* cp34-* cp35-* *i686 pp* *win32"
 
-  # Linux specific build settings
-
-  CIBW_BEFORE_ALL_LINUX: |
-    curl -OsL https://gitlab.com/libeigen/eigen/-/archive/3.3.7/eigen-3.3.7.tar.gz
-    tar xzf eigen-3.3.7.tar.gz eigen-3.3.7/Eigen --strip-components 1
-    tar xzf eigen-3.3.7.tar.gz eigen-3.3.7/unsupported --strip-components 1
-    mkdir -p {project}/include
-    cp -rf Eigen {project}/include
-    cp -rf unsupported {project}/include
-
   # MacOS specific build settings
 
   CIBW_BEFORE_ALL_MACOS: |
     brew cask uninstall --force oclint
-    brew install gcc eigen libomp
-
-  CIBW_ENVIRONMENT_MACOS: EIGEN_INCLUDE_DIR=/usr/local/Cellar/eigen/3.3.7/include/eigen3
-
-  # Windows specific build settings
-
-  CIBW_ENVIRONMENT_WINDOWS: EIGEN_INCLUDE_DIR="C:\\eigen-3.3.7\\"
+    brew install gcc libomp
 
   # Python build settings
 
@@ -68,16 +52,6 @@ jobs:
           python -m pip install --upgrade pip
           python -m pip install cibuildwheel==1.5.5
 
-      - name: Install Eigen on Windows
-        if: runner.os == 'Windows'
-        shell: powershell
-        env:
-          GIT_REDIRECT_STDERR: "2>&1"
-        run: |
-          choco install vcpython27 -f -y
-          Invoke-WebRequest -Uri "https://gitlab.com/libeigen/eigen/-/archive/3.3.7/eigen-3.3.7.zip" -UseBasicParsing -OutFile C:\eigen3.zip
-          & "C:\\Program Files\\7-Zip\\7z.exe" x C:\eigen3.zip -o"C:\" -y
-
       - name: Build wheels
         run: |
           python -m cibuildwheel --output-dir wheelhouse

.github/workflows/wheels.yml

@@ -8,27 +8,11 @@ on:
 env:
   CIBW_SKIP: "cp27-* cp34-* cp35-* *i686 pp* *win32"
 
-  # Linux specific build settings
-
-  CIBW_BEFORE_ALL_LINUX: |
-    curl -OsL https://gitlab.com/libeigen/eigen/-/archive/3.3.7/eigen-3.3.7.tar.gz
-    tar xzf eigen-3.3.7.tar.gz eigen-3.3.7/Eigen --strip-components 1
-    tar xzf eigen-3.3.7.tar.gz eigen-3.3.7/unsupported --strip-components 1
-    mkdir -p {project}/include
-    cp -rf Eigen {project}/include
-    cp -rf unsupported {project}/include
-
   # MacOS specific build settings
 
   CIBW_BEFORE_ALL_MACOS: |
     brew cask uninstall --force oclint
-    brew install gcc eigen libomp
-
-  CIBW_ENVIRONMENT_MACOS: EIGEN_INCLUDE_DIR=/usr/local/Cellar/eigen/3.3.7/include/eigen3
-
-  # Windows specific build settings
-
-  CIBW_ENVIRONMENT_WINDOWS: EIGEN_INCLUDE_DIR="C:\\eigen-3.3.7\\"
+    brew install gcc libomp
 
   # Python build settings
 
@@ -72,16 +56,6 @@ jobs:
           python -m pip install --upgrade pip
           python -m pip install cibuildwheel==1.5.5
 
-      - name: Install Eigen on Windows
-        if: runner.os == 'Windows'
-        shell: powershell
-        env:
-          GIT_REDIRECT_STDERR: "2>&1"
-        run: |
-          choco install vcpython27 -f -y
-          Invoke-WebRequest -Uri "https://gitlab.com/libeigen/eigen/-/archive/3.3.7/eigen-3.3.7.zip" -UseBasicParsing -OutFile C:\eigen3.zip
-          & "C:\\Program Files\\7-Zip\\7z.exe" x C:\eigen3.zip -o"C:\" -y
-
       - name: Build wheels
         run: |
           python -m cibuildwheel --output-dir wheelhouse

CHANGELOG.md

@@ -6,21 +6,24 @@
 
 ### Improvements
 
-* Add new lightweight backend with performance improvements
+* Add new lightweight backend with performance improvements.
   [(#57)](https://github.com/PennyLaneAI/pennylane-lightning/pull/57)
 
+* Remove the previous Eigen-based backend.
+  [(#67)](https://github.com/PennyLaneAI/pennylane-lightning/pull/67)
+
 ### Documentation
 
 ### Bug fixes
 
-* Re-add dispatch table after fixing static initialisation order issue
+* Re-add dispatch table after fixing static initialisation order issue.
   [(#68)](https://github.com/PennyLaneAI/pennylane-lightning/pull/68)
 
 ### Contributors
 
 This release contains contributions from (in alphabetical order):
 
-Thomas Loke
+Thomas Bromley, Christina Lee, Thomas Loke, Antal Száva.
 
 ---
 

README.rst

@@ -27,7 +27,7 @@ PennyLane-Lightning Plugin
 
 .. header-start-inclusion-marker-do-not-remove
 
-The PennyLane-Lightning plugin provides a fast state-vector simulator written in C++ using `Eigen <http://eigen.tuxfamily.org/index.php?title=Main_Page>`_.
+The PennyLane-Lightning plugin provides a fast state-vector simulator written in C++.
 
 `PennyLane <https://pennylane.readthedocs.io>`_ is a cross-platform Python library for quantum machine
 learning, automatic differentiation, and optimization of hybrid quantum-classical computations.
@@ -65,15 +65,14 @@ Note that subsequent calls to ``pip install -e .`` will use cached binaries stor
 The following dependencies are required to install PennyLane-Lightning:
 
 * A C++ compiler, such as ``g++``, ``clang``, or ``MSVC``.
-* `Eigen3 <http://eigen.tuxfamily.org/index.php?title=Main_Page>`_ - a C++ header library for linear algebra.
 * `pybind11 <https://pybind11.readthedocs.io/en/stable/>`_ a library for binding C++
   functionality to Python.
 
 On Debian-based systems, these can be installed via ``apt`` and ``pip``:
 
 .. code-block:: console
 
-    $ sudo apt install g++ libeigen3-dev
+    $ sudo apt install g++
     $ pip install pybind11
 
 Testing

doc/devices.rst

@@ -2,7 +2,7 @@ Lightning Qubit device
 ======================
 
 The ``lightning.qubit`` device is an extension of PennyLane's built-in ``default.qubit`` device.
-It uses the C++ `Eigen <http://eigen.tuxfamily.org/index.php?title=Main_Page>`__ library to
+It uses a custom-built backend to
 perform fast linear algebra calculations for simulating quantum state-vector evolution.
 
 A ``lightning.qubit`` device can be loaded using:

lightning_benchmark.ipynb

@@ -15,4 +15,3 @@
 
 from ._version import __version__
 from .lightning_qubit import LightningQubit
-from .lightning_qubit_new import LightningQubitNew

pennylane_lightning/__init__.py

@@ -1,4 +1,4 @@
-# Copyright 2020 Xanadu Quantum Technologies Inc.
+# Copyright 2021 Xanadu Quantum Technologies Inc.
 
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -15,12 +15,10 @@
 This module contains the :class:`~.LightningQubit` class, a PennyLane simulator device that
 interfaces with C++ for fast linear algebra calculations.
 """
-import warnings
-
 from pennylane.devices import DefaultQubit
 from .lightning_qubit_ops import apply
 import numpy as np
-from pennylane import QubitStateVector, BasisState, DeviceError
+from pennylane import QubitStateVector, BasisState, DeviceError, QubitUnitary
 
 from ._version import __version__
 
@@ -29,17 +27,11 @@ class LightningQubit(DefaultQubit):
     """PennyLane Lightning device.
 
     An extension of PennyLane's built-in ``default.qubit`` device that interfaces with C++ to
-    perform fast linear algebra calculations using the
-    `Eigen <http://eigen.tuxfamily.org/index.php?title=Main_Page>`__ library.
+    perform fast linear algebra calculations.
 
     Use of this device requires pre-built binaries or compilation from source. Check out the
     :doc:`/installation` guide for more details.
 
-    .. warning::
-
-        The C++ interface currently supports up to 50 wires. If Lightning Qubit is loaded with
-        more than 50 wires, it will revert to a NumPy-based simulation.
-
     Args:
         wires (int): the number of wires to initialize the device with
         shots (int): How many times the circuit should be evaluated (or sampled) to estimate
@@ -82,21 +74,11 @@ class LightningQubit(DefaultQubit):
         "CRot",
     }
 
-    observables = {"PauliX", "PauliY", "PauliZ", "Hadamard", "Identity"}
-
-    _MAX_WIRES = 50
-    """Maximum number of supported wires. Beyond this number, lightning.qubit behaves like 
-    default.qubit."""
+    observables = {"PauliX", "PauliY", "PauliZ", "Hadamard", "Hermitian", "Identity"}
 
     def __init__(self, wires, *, shots=1000, analytic=True):
         super().__init__(wires, shots=shots, analytic=analytic)
 
-        if self.num_wires > self._MAX_WIRES:
-            warnings.warn(
-                f"The number of wires exceeds {self._MAX_WIRES}, reverting to NumPy-based evaluation.",
-                UserWarning,
-            )
-
     @classmethod
     def capabilities(cls):
         capabilities = super().capabilities().copy()
@@ -112,14 +94,10 @@ def capabilities(cls):
 
     def apply(self, operations, rotations=None, **kwargs):
 
-        if self.num_wires > self._MAX_WIRES:
-            super().apply(operations, rotations=rotations, **kwargs)
-            return
-
         # State preparation is currently done in Python
         if operations:  # make sure operations[0] exists
             if isinstance(operations[0], QubitStateVector):
-                self._apply_state_vector(operations[0].parameters[0], operations[0].wires)
+                self._apply_state_vector(operations[0].parameters[0].copy(), operations[0].wires)
                 del operations[0]
             elif isinstance(operations[0], BasisState):
                 self._apply_basis_state(operations[0].parameters[0], operations[0].wires)
@@ -138,7 +116,10 @@ def apply(self, operations, rotations=None, **kwargs):
             self._pre_rotated_state = self._state
 
         if rotations:
-            self._state = self.apply_lightning(self._pre_rotated_state, rotations)
+            if any(isinstance(r, QubitUnitary) for r in rotations):
+                super().apply(operations=[], rotations=rotations)
+            else:
+                self._state = self.apply_lightning(np.copy(self._pre_rotated_state), rotations)
         else:
             self._state = self._pre_rotated_state
 
@@ -156,6 +137,6 @@ def apply_lightning(self, state, operations):
         op_wires = [self.wires.indices(o.wires) for o in operations]
         op_param = [o.parameters for o in operations]
 
-        state_vector = np.ravel(state, order="F")
-        state_vector_updated = apply(state_vector, op_names, op_wires, op_param, self.num_wires)
-        return np.reshape(state_vector_updated, state.shape, order="F")
+        state_vector = np.ravel(state)
+        apply(state_vector, op_names, op_wires, op_param, self.num_wires)
+        return np.reshape(state_vector, state.shape)