Add ENABLE_LAPACK

.github/CHANGELOG.md

@@ -88,6 +88,9 @@
 * Add `workflow_dispatch` to wheels recipes; allowing developers to build wheels manually on a branch instead of temporarily changing the headers.
   [(#679)](https://github.com/PennyLaneAI/pennylane-lightning/pull/679)
 
+* Add the `ENABLE_LAPACK` compilation flag to toggle dynamic linking to LAPACK library.
+  [(#678)](https://github.com/PennyLaneAI/pennylane-lightning/pull/678)
+
 ### Documentation
 
 ### Bug fixes

.github/workflows/tests_windows.yml

@@ -126,6 +126,7 @@ jobs:
               -DBUILD_TESTS=ON `
               -DENABLE_OPENMP=OFF `
               -DENABLE_PYTHON=OFF `
+              -DENABLE_LAPACK=OFF `
               -DENABLE_GATE_DISPATCHER=OFF `
               -DPL_BACKEND=${{ matrix.pl_backend }} `
               -DENABLE_WARNINGS=OFF
@@ -187,7 +188,7 @@ jobs:
 
       - name: Install dependencies
         run: |
-          python -m pip install cmake build ninja scipy
+          python -m pip install cmake build ninja
 
       - name: Checkout PennyLane-Lightning
         uses: actions/checkout@v4

.github/workflows/wheel_linux_aarch64.yml

@@ -131,10 +131,9 @@ jobs:
           # Python build settings
           CIBW_BEFORE_BUILD: |
             cat /etc/yum.conf | sed "s/\[main\]/\[main\]\ntimeout=5/g" > /etc/yum.conf
-            python -m pip install ninja cmake~=3.24.0 scipy
+            python -m pip install ninja cmake~=3.24.0
 
-          CIBW_ENVIRONMENT: |
-            PL_BACKEND="${{ matrix.pl_backend }}"
+          CIBW_ENVIRONMENT: PL_BACKEND="${{ matrix.pl_backend }}" CMAKE_ARGS="-DENABLE_LAPACK=OFF"
 
           CIBW_MANYLINUX_AARCH64_IMAGE: manylinux2014
 

.github/workflows/wheel_linux_ppc64le.yml

@@ -130,10 +130,9 @@ jobs:
           # Python build settings
           CIBW_BEFORE_BUILD: |
             cat /etc/yum.conf | sed "s/\[main\]/\[main\]\ntimeout=5/g" > /etc/yum.conf
-            python -m pip install ninja cmake~=3.24.0 scipy
+            python -m pip install ninja cmake~=3.24.0
 
-          CIBW_ENVIRONMENT: |
-            PL_BACKEND="${{ matrix.pl_backend }}"
+          CIBW_ENVIRONMENT: PL_BACKEND="${{ matrix.pl_backend }}" CMAKE_ARGS="-DENABLE_LAPACK=OFF"
 
           CIBW_MANYLINUX_PPC64LE_IMAGE: manylinux2014
 

.github/workflows/wheel_win_x86_64.yml

@@ -127,6 +127,7 @@ jobs:
             python -m pip install pybind11 cmake~=3.24.0 build
 
           CIBW_ENVIRONMENT: |
+            CMAKE_ARGS="-DENABLE_LAPACK=OFF"
             PL_BACKEND="${{ matrix.pl_backend }}"
 
           CIBW_MANYLINUX_X86_64_IMAGE: manylinux2014

CMakeLists.txt

@@ -47,6 +47,8 @@ option(ENABLE_WARNINGS "Enable warnings" ON)
 option(ENABLE_NATIVE "Enable native CPU build tuning" OFF)
 option(ENABLE_PYTHON "Enable compilation of the Python module" ON)
 
+option(ENABLE_LAPACK "Enable compilation with scipy/LAPACK" ON)
+
 # OpenMP
 find_package(OpenMP)
 if (OpenMP_CXX_FOUND)
@@ -81,39 +83,42 @@ set(CMAKE_POLICY_DEFAULT_CMP0127 NEW) # To suppress pybind11 CMP0127 warning
 # Add pybind11
 include(FetchContent)
 
-# TODO: Add a flag to toggle the Python requirement.
-find_package(Python COMPONENTS Interpreter Development)
-message("Python site-packages directory: ${Python_SITELIB}")
-set(SCIPYLIBS ${Python_SITELIB})
-
-if(CMAKE_SYSTEM_NAME MATCHES "Darwin")
-    set(SCIPYLIBS "/System/Library/Frameworks/Accelerate.framework/Versions/Current/Frameworks/vecLib.framework/libLAPACK.dylib")
-elseif(CMAKE_SYSTEM_NAME MATCHES "Linux")
-    if(EXISTS ${SCIPYLIBS}/scipy.libs)
-        set(SCIPYLIBS ${SCIPYLIBS}/scipy.libs)
+if(ENABLE_LAPACK)
+    find_package(Python COMPONENTS Interpreter Development)
+    set(SCIPYLIBS ${Python_SITELIB})
+
+    if(CMAKE_SYSTEM_NAME MATCHES "Darwin")
+        set(SCIPYLIBS "/System/Library/Frameworks/Accelerate.framework/Versions/Current/Frameworks/vecLib.framework/libLAPACK.dylib")
+    elseif(CMAKE_SYSTEM_NAME MATCHES "Linux")
+        if(EXISTS ${SCIPYLIBS}/scipy.libs)
+            set(SCIPYLIBS ${SCIPYLIBS}/scipy.libs)
+        else()
+            # Fallback to the lib path of Python for `conda` support
+            set(SCIPYLIBS ${SCIPYLIBS}/../..)
+        endif()
+    elseif(CMAKE_SYSTEM_NAME MATCHES "Windows")
     else()
-        # Fallback to the lib path of Python for `conda` support
-        set(SCIPYLIBS ${SCIPYLIBS}/../..)
+        message(FATAL_ERROR "Unsupported platform: ${CMAKE_SYSTEM_NAME}")
     endif()
-elseif(CMAKE_SYSTEM_NAME MATCHES "Windows")
-    # TODO: add windows support
-    #    string(REPLACE "\\" "/" SCIPYLIBS "${SCIPYLIBS}")
-    #    message("Python site-packages directory (Windows): ${SCIPYLIBS}")
-else()
-    message(FATAL_ERROR "Unsupported platform: ${CMAKE_SYSTEM_NAME}")
-endif()
 
-configure_file(${CMAKE_CURRENT_SOURCE_DIR}/pennylane_lightning/core/src/utils/config.h.in
-    ${CMAKE_CURRENT_SOURCE_DIR}/pennylane_lightning/core/src/utils/config.h)
+    configure_file(${CMAKE_CURRENT_SOURCE_DIR}/pennylane_lightning/core/src/utils/config.h.in
+        ${CMAKE_CURRENT_SOURCE_DIR}/pennylane_lightning/core/src/utils/config.h)
+
+    message(STATUS "Python scipy-lib path: ${SCIPYLIBS}")
+endif()
 
 if(ENABLE_PYTHON)
+    find_package(Python COMPONENTS Interpreter Development)
     FetchContent_Declare(pybind11
                         GIT_REPOSITORY https://github.com/pybind/pybind11.git
                         GIT_TAG        v2.11.1
     )
     FetchContent_MakeAvailable(pybind11)
 endif()
 
+# Print Python site-packages directory for reference
+message("Python site-packages directory: ${Python_SITELIB}")
+
 set (CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR})
 
 # All CMakeLists.txt in subdirectories use pennylane_lightning_compile_options and pennylane_lightning_external_libs

cmake/process_options.cmake

@@ -101,3 +101,6 @@ if (UNIX AND (${CMAKE_SYSTEM_PROCESSOR} MATCHES "(AMD64)|(X64)|(x64)|(x86_64)"))
     target_compile_options(lightning_compile_options INTERFACE -mavx)
 endif()
 
+if(ENABLE_LAPACK)
+    target_compile_options(lightning_compile_options INTERFACE "-DPL_USE_LAPACK=1")
+endif()

pennylane_lightning/core/src/measurements/tests/Test_MeasurementsBase.cpp

@@ -570,7 +570,7 @@ TEST_CASE("Expval Shot- NamedObs", "[MeasurementsBase][Observables]") {
     }
 }
 
-#ifndef _MSC_VER
+#ifdef PL_USE_LAPACK
 template <typename TypeList> void testHermitianObsExpvalShot() {
     if constexpr (!std::is_same_v<TypeList, void>) {
         using StateVectorT = typename TypeList::Type;
@@ -839,7 +839,7 @@ template <typename TypeList> void testTensorProdObsExpvalShot() {
                                      expected, static_cast<PrecisionT>(0.20)));
         }
 
-#ifndef _MSC_VER
+#ifdef PL_USE_LAPACK
         DYNAMIC_SECTION(" With Identity and shots_range"
                         << StateVectorToName<StateVectorT>::name) {
             size_t num_shots = 80000;
@@ -1011,7 +1011,7 @@ TEST_CASE("Var - HermitianObs", "[MeasurementsBase][Observables]") {
     }
 }
 
-#ifndef _MSC_VER
+#ifdef PL_USE_LAPACK
 template <typename TypeList> void testHermitianObsShotVar() {
     if constexpr (!std::is_same_v<TypeList, void>) {
         using StateVectorT = typename TypeList::Type;
@@ -1147,7 +1147,7 @@ template <typename TypeList> void testTensorProdObsVarShot() {
                                      expected, static_cast<PrecisionT>(0.20)));
         }
 
-#ifndef _MSC_VER
+#ifdef PL_USE_LAPACK
         DYNAMIC_SECTION("With Hermitian and NameObs"
                         << StateVectorToName<StateVectorT>::name) {
             using MatrixT = std::vector<ComplexT>;
@@ -1555,7 +1555,7 @@ template <typename TypeList> void testHamiltonianObsExpvalShot() {
             REQUIRE_THAT(res, Catch::Matchers::WithinRel(
                                   expected, static_cast<PrecisionT>(0.20)));
         }
-#ifndef _MSC_VER
+#ifdef PL_USE_LAPACK
         DYNAMIC_SECTION("YHer" << StateVectorToName<StateVectorT>::name) {
             auto Y0 = std::make_shared<NamedObs<StateVectorT>>(
                 "PauliY", std::vector<size_t>{0});
@@ -1636,6 +1636,7 @@ template <typename TypeList> void testHamiltonianObsVarShot() {
                                   expected, static_cast<PrecisionT>(0.20)));
         }
 
+#ifdef PL_USE_LAPACK
         DYNAMIC_SECTION("YHer" << StateVectorToName<StateVectorT>::name) {
             using ComplexT = typename StateVectorT::ComplexT;
             auto Y0 = std::make_shared<NamedObs<StateVectorT>>(
@@ -1664,6 +1665,7 @@ template <typename TypeList> void testHamiltonianObsVarShot() {
             REQUIRE_THAT(res, Catch::Matchers::WithinRel(
                                   expected, static_cast<PrecisionT>(0.20)));
         }
+#endif
 
         testHamiltonianObsVarShot<typename TypeList::Next>();
     }

pennylane_lightning/core/src/observables/Observables.hpp

@@ -23,7 +23,7 @@
 #include "Error.hpp"
 #include "Util.hpp"
 
-#ifndef _MSC_VER
+#ifdef PL_USE_LAPACK
 #include "UtilLinearAlg.hpp"
 #endif
 
@@ -220,7 +220,7 @@ class HermitianObsBase : public Observable<StateVectorT> {
     MatrixT matrix_;
     std::vector<size_t> wires_;
 
-#ifndef _MSC_VER
+#ifdef PL_USE_LAPACK
     std::vector<PrecisionT> eigenVals_;
     MatrixT unitary_;
 #endif
@@ -245,7 +245,7 @@ class HermitianObsBase : public Observable<StateVectorT> {
         : matrix_{std::move(matrix)}, wires_{std::move(wires)} {
         PL_ASSERT(matrix_.size() == Util::exp2(2 * wires_.size()));
 
-#ifndef _MSC_VER
+#ifdef PL_USE_LAPACK
         std::vector<std::complex<PrecisionT>> mat(matrix_.size());
 
         std::transform(matrix_.begin(), matrix_.end(), mat.begin(),
@@ -284,7 +284,7 @@ class HermitianObsBase : public Observable<StateVectorT> {
         [[maybe_unused]] StateVectorT &sv,
         [[maybe_unused]] std::vector<std::vector<PrecisionT>> &eigenValues,
         [[maybe_unused]] std::vector<size_t> &ob_wires) const override {
-#ifndef _MSC_VER
+#ifdef PL_USE_LAPACK
         std::vector<std::complex<PrecisionT>> mat(matrix_.size());
 
         std::transform(matrix_.begin(), matrix_.end(), mat.begin(),
@@ -303,8 +303,10 @@ class HermitianObsBase : public Observable<StateVectorT> {
         sv.applyMatrix(unitary_, wires_);
         eigenValues.push_back(eigenVals_);
 #else
-        PL_ABORT("Hermitian observables do not support shot measurement for "
-                 "Windows.");
+        PL_ABORT(
+            "Hermitian observables with shot measurement are not supported; "
+            "consider building the device with `ENABLE_LAPACK=ON` compilation "
+            "flag.");
 #endif
     }
 };

pennylane_lightning/core/src/observables/tests/Test_Observables.cpp

@@ -207,7 +207,7 @@ template <typename TypeList> void testHermitianObsBase() {
             REQUIRE(ob2 != ob3);
         }
 
-#ifndef _MSC_VER
+#ifdef PL_USE_LAPACK
         DYNAMIC_SECTION("Failed to create a HermitianObs- "
                         << StateVectorToName<StateVectorT>::name) {
             std::mt19937_64 re{1337};
@@ -244,9 +244,8 @@ template <typename TypeList> void testHermitianObsBase() {
 
             REQUIRE_THROWS_WITH(
                 obs.applyInPlaceShots(state_vector, eigenValues, ob_wires),
-                Catch::Matchers::Contains(
-                    "Hermitian observables do not support shot measurement for "
-                    "Windows."));
+                Catch::Matchers::Contains("Hermitian observables with shot "
+                                          "measurement are not supported"));
         }
 #endif
 

pennylane_lightning/core/src/utils/CMakeLists.txt

@@ -7,7 +7,7 @@ set(LQUBIT_UTILS_FILES RuntimeInfo.cpp CACHE INTERNAL "" FORCE)
 
 add_library(lightning_utils STATIC ${LQUBIT_UTILS_FILES})
 
-if(NOT WIN32)
+if(ENABLE_LAPACK)
     list(APPEND LQUBIT_UTILS_FILES UtilLinearAlg.cpp)
 endif()
 

pennylane_lightning/core/src/utils/tests/CMakeLists.txt

@@ -34,7 +34,7 @@ set(TEST_SOURCES    Test_BitUtil.cpp
                     Test_Util.cpp
                     )
 
-if(NOT WIN32)
+if(ENABLE_LAPACK)
     list(APPEND TEST_SOURCES Test_UtilLinearAlg.cpp)
 endif()