⬆️ Update munich-quantum-toolkit/core (#610)

mqt-app[bot] · denialhaag · burgholzer · web-flow · commit cf2b59b9696f · 2025-08-01T11:33:14.000Z
This pull request updates the [munich-quantum-toolkit/core](https://github.com/munich-quantum-toolkit/core) dependency from munich-quantum-toolkit/core@1f95d92 (version v3.1.0) to munich-quantum-toolkit/core@28e41bf (version v3.2.0). **Full Changelog**: munich-quantum-toolkit/core@1f95d92...28e41bf --------- Signed-off-by: Daniel Haag <121057143+denialhaag@users.noreply.github.com> Co-authored-by: mqt-app[bot] <219534693+mqt-app[bot]@users.noreply.github.com> Co-authored-by: Daniel Haag <121057143+denialhaag@users.noreply.github.com> Co-authored-by: Lukas Burgholzer <burgholzer@me.com>
diff --git a/.clang-format b/.clang-format
@@ -1,3 +1,4 @@
 BasedOnStyle: LLVM
 IncludeBlocks: Regroup
 PointerAlignment: Left
+Standard: c++20
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
@@ -88,6 +88,12 @@ jobs:
           [ubuntu-22.04, ubuntu-24.04, ubuntu-22.04-arm, ubuntu-24.04-arm]
         compiler: [gcc, clang, clang-19, clang-20]
         config: [Release, Debug]
+        exclude:
+          # both combinations do not support C++20 due to the compiler being too old
+          - runs-on: ubuntu-22.04
+            compiler: clang
+          - runs-on: ubuntu-22.04-arm
+            compiler: clang
     uses: munich-quantum-toolkit/workflows/.github/workflows/reusable-cpp-tests-ubuntu.yml@v1.16
     with:
       runs-on: ${{ matrix.runs-on }}
@@ -153,6 +159,7 @@ jobs:
       files-changed-only: true
       install-pkgs: "pybind11==3.0.0"
       setup-python: true
+      cpp-linter-extra-args: "-std=c++20"
 
   python-tests:
     name: 🐍 Test
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -18,7 +18,9 @@ _If you are upgrading: please see [`UPGRADING.md`](UPGRADING.md#Unreleased)._
 
 ### Changed
 
-- ✨ Expose enums to Python via `pybind11`'s new (`enum.Enum`-compatible) `py::native_enum` ([#607]) ([**@denialhaag**])
+- **Breaking**: ⬆️ Bump minimum required `mqt-core` version to `3.2.1` ([#610]) ([**@denialhaag**])
+- **Breaking**: ⬆️ Require C++20 ([#610]) ([**@denialhaag**])
+- **Breaking**: ✨ Expose enums to Python via `pybind11`'s new (`enum.Enum`-compatible) `py::native_enum` ([#607]) ([**@denialhaag**])
 - **Breaking**: ⬆️ Bump minimum required `mqt-core` version to `3.1.0` ([#591]) ([**@denialhaag**])
 - **Breaking**: ⬆️ Bump minimum required `pybind11` version to `3.0.0` ([#591]) ([**@denialhaag**])
 - ♻️ Move the C++ code for the Python bindings to the top-level `bindings` directory ([#567]) ([**@denialhaag**])
@@ -51,6 +53,7 @@ _📚 Refer to the [GitHub Release Notes] for previous changelogs._
 
 <!-- PR links -->
 
+[#610]: https://github.com/munich-quantum-toolkit/ddsim/pull/610
 [#608]: https://github.com/munich-quantum-toolkit/ddsim/pull/608
 [#607]: https://github.com/munich-quantum-toolkit/ddsim/pull/607
 [#606]: https://github.com/munich-quantum-toolkit/ddsim/pull/606
diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -14,6 +14,8 @@ project(
   LANGUAGES C CXX
   DESCRIPTION "MQT DDSIM - A quantum circuit simulator based on decision diagrams")
 
+set(CMAKE_CXX_STANDARD 20)
+
 option(BUILD_MQT_DDSIM_BINDINGS "Build the MQT DDSIM Python bindings" OFF)
 if(BUILD_MQT_DDSIM_BINDINGS)
   # ensure that the BINDINGS option is set
diff --git a/README.md b/README.md
@@ -61,7 +61,7 @@ print(counts)
 
 ## System Requirements and Building
 
-The implementation is compatible with any C++17 compiler and a minimum CMake version of 3.24.
+The implementation is compatible with any C++20 compiler and a minimum CMake version of 3.24.
 Please refer to the [documentation](https://mqt.readthedocs.io/projects/ddsim) on how to build the project.
 
 Building (and running) is continuously tested under Linux, macOS, and Windows using the [latest available system versions for GitHub Actions](https://github.com/actions/virtual-environments).
diff --git a/UPGRADING.md b/UPGRADING.md
@@ -42,6 +42,9 @@ The `ConstructionMode`, `HybridMode`, and `PathSimulatorMode` enums are now expo
 As a result, the enums can no longer be initialized using a string.
 Instead of `PathSimulatorMode("sequential")` or `"sequential"`, use `PathSimulatorMode.sequential`.
 
+Finally, the minimum required C++ version has been raised from C++17 to C++20.
+The default compilers of our test systems support all relevant features of the standard.
+
 <!-- Version links -->
 
 [unreleased]: https://github.com/munich-quantum-toolkit/qmap/compare/v1.24.0...HEAD
diff --git a/cmake/ExternalDependencies.cmake b/cmake/ExternalDependencies.cmake
@@ -41,11 +41,11 @@ if(BUILD_MQT_DDSIM_BINDINGS)
 endif()
 
 # cmake-format: off
-set(MQT_CORE_MINIMUM_VERSION 3.1.0
+set(MQT_CORE_MINIMUM_VERSION 3.2.1
     CACHE STRING "MQT Core minimum version")
-set(MQT_CORE_VERSION 3.1.0
+set(MQT_CORE_VERSION 3.2.1
     CACHE STRING "MQT Core version")
-set(MQT_CORE_REV "1f95d92320b116497d6f516a085fbe3bb8693960"
+set(MQT_CORE_REV "0425f88169f573e4505b49703c4cadf3699ccbcd"
     CACHE STRING "MQT Core identifier (tag, branch or commit hash)")
 set(MQT_CORE_REPO_OWNER "munich-quantum-toolkit"
     CACHE STRING "MQT Core repository owner (change when using a fork)")
diff --git a/docs/development_guide.md b/docs/development_guide.md
@@ -118,7 +118,7 @@ Ready to contribute to the project? This guide will get you started.
 
 ## Working on the C++ library
 
-Building the project requires a C++ compiler supporting _C++17_ and CMake with a minimum version of _3.24_.
+Building the project requires a C++ compiler supporting _C++20_ and CMake with a minimum version of _3.24_.
 As of 2025, our CI pipeline on GitHub continuously tests the library under the following matrix of systems and compilers:
 
 - Ubuntu 24.04 with GCC 13 or Clang 18 on x86_64 and arm64
diff --git a/docs/index.md b/docs/index.md
@@ -4,7 +4,7 @@
 \begin{abstract}
 ```
 
-MQT DDSIM is an open-source C++17 and Python library for classical quantum circuit simulation developed as part of the _{doc}`Munich Quantum Toolkit (MQT) <mqt:index>`_ [^1].
+MQT DDSIM is an open-source C++20 and Python library for classical quantum circuit simulation developed as part of the _{doc}`Munich Quantum Toolkit (MQT) <mqt:index>`_ [^1].
 
 This documentation provides a comprehensive guide to the MQT DDSIM library, including {doc}`installation instructions <installation>`, a {doc}`quickstart guide <quickstart>`, and detailed {doc}`API documentation <api/mqt/ddsim/index>`.
 The source code of MQT DDSIM is publicly available on GitHub at [munich-quantum-toolkit/ddsim](https://github.com/munich-quantum-toolkit/ddsim), while pre-built binaries are available via [PyPI](https://pypi.org/project/mqt.ddsim/) for all major operating systems and all modern Python versions.
diff --git a/docs/installation.md b/docs/installation.md
@@ -1,6 +1,6 @@
 # Installation
 
-MQT DDSIM is mainly developed as a C++17 library with Python bindings.
+MQT DDSIM is mainly developed as a C++20 library with Python bindings.
 The resulting Python package is available on [PyPI](https://pypi.org/project/mqt.ddsim/) and can be installed on all major operating systems using all modern Python versions.
 
 :::::{tip}
@@ -96,7 +96,7 @@ $ uv pip install mqt.ddsim --no-binary mqt.ddsim --no-binary mqt.core
 :::
 ::::
 
-This requires a [C++ compiler supporting C++17](https://en.wikipedia.org/wiki/List_of_compilers#C++_compilers) and a minimum [CMake](https://cmake.org/) version of 3.24.
+This requires a [C++ compiler supporting C++20](https://en.wikipedia.org/wiki/List_of_compilers#C++_compilers) and a minimum [CMake](https://cmake.org/) version of 3.24.
 The library is continuously tested under Linux, MacOS, and Windows using the [latest available system versions for GitHub Actions](https://github.com/actions/virtual-environments).
 In order to access the latest build logs, visit the [GitHub Actions page](https://github.com/munich-quantum-toolkit/ddsim/actions/workflows/ci.yml).
 
diff --git a/pyproject.toml b/pyproject.toml
@@ -11,7 +11,7 @@ requires = [
     "scikit-build-core>=0.11.2",
     "setuptools-scm>=8.3.1",
     "pybind11>=3.0.0",
-    "mqt.core~=3.1.0",
+    "mqt.core~=3.2.1",
 ]
 build-backend = "scikit_build_core.build"
 
@@ -48,7 +48,7 @@ classifiers = [
 ]
 requires-python = ">=3.9"
 dependencies = [
-    "mqt.core[qiskit]~=3.1.0",
+    "mqt.core[qiskit]~=3.2.1",
     "qiskit>=1.1",
 ]
 dynamic = ["version"]
@@ -300,10 +300,10 @@ test-skip = [
 environment = { DEPLOY = "ON" }
 # The SOVERSION needs to be updated when the shared libraries are updated.
 repair-wheel-command = """auditwheel repair -w {dest_dir} {wheel} \
---exclude libmqt-core-ir.so.3.1 \
---exclude libmqt-core-qasm.so.3.1 \
---exclude libmqt-core-circuit-optimizer.so.3.1 \
---exclude libmqt-core-dd.so.3.1"""
+--exclude libmqt-core-ir.so.3.2 \
+--exclude libmqt-core-qasm.so.3.2 \
+--exclude libmqt-core-circuit-optimizer.so.3.2 \
+--exclude libmqt-core-dd.so.3.2"""
 
 [tool.cibuildwheel.macos]
 environment = { MACOSX_DEPLOYMENT_TARGET = "10.15" }
@@ -336,7 +336,7 @@ build = [
   "pybind11>=3.0.0",
   "scikit-build-core>=0.11.2",
   "setuptools-scm>=8.3.1",
-  "mqt.core~=3.1.0",
+  "mqt.core~=3.2.1",
 ]
 docs = [
   "furo>=2024.8.6",
diff --git a/src/ShorFastSimulator.cpp b/src/ShorFastSimulator.cpp
@@ -464,7 +464,7 @@ void ShorFastSimulator::uAEmulate2Rec(dd::vEdge e) {
     return;
   }
   auto& nodes = nodesOnLevel.at(static_cast<std::size_t>(e.p->v));
-  if (nodes.find(e.p) != nodes.end()) {
+  if (nodes.contains(e.p)) {
     return;
   }
   nodes[e.p] = dd::vCachedEdge::zero();
diff --git a/src/ShorSimulator.cpp b/src/ShorSimulator.cpp
@@ -110,8 +110,7 @@ ShorSimulator::simulate([[maybe_unused]] std::size_t shots) {
   }
 
   // EXACT QFT
-  for (std::int32_t i = 0; i < static_cast<std::int32_t>(2 * requiredBits);
-       i++) {
+  for (std::int32_t i = 0; std::cmp_less(i, 2 * requiredBits); i++) {
     if (verbose) {
       std::clog << "[ " << i + 1 << "/" << 2 * requiredBits
                 << " ] QFT Pass. dd size=" << rootEdge.size() << "\n";
diff --git a/src/Simulator.cpp b/src/Simulator.cpp
@@ -24,6 +24,7 @@
 #include <cmath>
 #include <complex>
 #include <cstddef>
+#include <functional>
 #include <iostream>
 #include <iterator>
 #include <map>
@@ -58,11 +59,9 @@ std::map<std::string, std::size_t> Simulator::sampleFromAmplitudeVectorInPlace(
   for (unsigned int i = 0; i < shots; ++i) {
     auto p = dist(mt);
     // use binary search to find the first entry >= p
-    auto mit =
-        std::upper_bound(amplitudes.begin(), amplitudes.end(), p,
-                         [](const dd::fp val, const std::complex<dd::fp>& c) {
-                           return val < c.real();
-                         });
+    auto mit = std::ranges::upper_bound(
+        amplitudes, p, std::less<>{},
+        [](const std::complex<dd::fp>& c) { return c.real(); });
     auto m = std::distance(amplitudes.begin(), mit);
 
     // construct basis state string
@@ -98,7 +97,7 @@ Simulator::getNodeContributions(const dd::vEdge& edge) const {
     const dd::fp parentProb = probsMone[ptr];
 
     if (ptr->e.at(0).p != nullptr && !ptr->e.at(0).w.exactlyZero()) {
-      if (probsMone.find(ptr->e.at(0).p) == probsMone.end()) {
+      if (!probsMone.contains(ptr->e.at(0).p)) {
         q.push(ptr->e.at(0).p);
         probsMone[ptr->e.at(0).p] = 0;
       }
@@ -107,7 +106,7 @@ Simulator::getNodeContributions(const dd::vEdge& edge) const {
     }
 
     if (ptr->e.at(1).p != nullptr && !ptr->e.at(1).w.exactlyZero()) {
-      if (probsMone.find(ptr->e.at(1).p) == probsMone.end()) {
+      if (!probsMone.contains(ptr->e.at(1).p)) {
         q.push(ptr->e.at(1).p);
         probsMone[ptr->e.at(1).p] = 0;
       }
@@ -259,13 +258,13 @@ double Simulator::approximateBySampling(std::unique_ptr<dd::Package>& localDD,
     q.pop();
 
     if (ptr->e.at(0).p != nullptr && !ptr->e.at(0).w.approximatelyZero() &&
-        visitedNodes2.find(ptr->e.at(0).p) == visitedNodes2.end()) {
+        !visitedNodes2.contains(ptr->e.at(0).p)) {
       visitedNodes2.insert(ptr->e.at(0).p);
       q.push(ptr->e.at(0).p);
     }
 
     if (ptr->e.at(1).p != nullptr && !ptr->e.at(1).w.approximatelyZero() &&
-        visitedNodes2.find(ptr->e.at(1).p) == visitedNodes2.end()) {
+        !visitedNodes2.contains(ptr->e.at(1).p)) {
       visitedNodes2.insert(ptr->e.at(1).p);
       q.push(ptr->e.at(1).p);
     }
diff --git a/test/test_det_noise_sim.cpp b/test/test_det_noise_sim.cpp
@@ -133,7 +133,7 @@ TEST(DeterministicNoiseSimTest, SimulateAdder4TrackAPDWithSimulate) {
                  907, 4145, 235, 262, 184, 116, 110};
   const auto tolerance = 100;
   for (std::size_t i = 0; i < expectedEntries.size(); ++i) {
-    if (m.count(expectedEntries.at(i)) == 0) {
+    if (!m.contains(expectedEntries.at(i))) {
       FAIL() << "Expected entry " << expectedEntries.at(i)
              << " not found in result";
     }
@@ -164,7 +164,7 @@ TEST(DeterministicNoiseSimTest, SimulateAdder4TrackD) {
       0.0186346925411, 0.0275086747656};
   const auto tolerance = 1e-10;
   for (std::size_t i = 0; i < expectedEntries.size(); ++i) {
-    if (m.count(expectedEntries.at(i)) == 0) {
+    if (!m.contains(expectedEntries.at(i))) {
       FAIL() << "Expected entry " << expectedEntries.at(i)
              << " not found in result";
     }
@@ -195,7 +195,7 @@ TEST(DeterministicNoiseSimTest, SimulateAdder4TrackAPD) {
       0.0184033482066, 0.0116282811276, 0.0110373166627};
   const auto tolerance = 1e-10;
   for (std::size_t i = 0; i < expectedEntries.size(); ++i) {
-    if (m.count(expectedEntries.at(i)) == 0) {
+    if (!m.contains(expectedEntries.at(i))) {
       FAIL() << "Expected entry " << expectedEntries.at(i)
              << " not found in result";
     }
@@ -221,7 +221,7 @@ TEST(DeterministicNoiseSimTest, SimulateAdder4TrackAP) {
       std::array{0.03008702498522842, 0.9364832248561167};
   const auto tolerance = 1e-10;
   for (std::size_t i = 0; i < expectedEntries.size(); ++i) {
-    if (m.count(expectedEntries.at(i)) == 0) {
+    if (!m.contains(expectedEntries.at(i))) {
       FAIL() << "Expected entry " << expectedEntries.at(i)
              << " not found in result";
     }
@@ -261,7 +261,7 @@ TEST(DeterministicNoiseSimTest, SimulateAdder4TrackAPDCustomProb) {
       0.0157508473593, 0.0187340765889, 0.0132640682125};
   const auto tolerance = 1e-10;
   for (std::size_t i = 0; i < expectedEntries.size(); ++i) {
-    if (m.count(expectedEntries.at(i)) == 0) {
+    if (!m.contains(expectedEntries.at(i))) {
       FAIL() << "Expected entry " << expectedEntries.at(i)
              << " not found in result";
     }
@@ -282,7 +282,7 @@ TEST(DeterministicNoiseSimTest, SimulateAdder4TrackAPDWithShots) {
   const auto expectedValues = std::array{616, 1487, 570, 5519};
   const std::size_t tolerance = 500;
   for (std::size_t i = 0; i < expectedEntries.size(); ++i) {
-    if (m.count(expectedEntries.at(i)) == 0) {
+    if (!m.contains(expectedEntries.at(i))) {
       FAIL() << "Expected entry " << expectedEntries.at(i)
              << " not found in result";
     }
@@ -304,7 +304,7 @@ TEST(DeterministicNoiseSimTest, SimulateAdder4NoNoise1) {
   std::cout << std::setw(2) << nlohmann::basic_json(m) << "\n";
 
   const double tolerance = 1e-10;
-  if (m.count("1001") == 0) {
+  if (!m.contains("1001")) {
     FAIL() << "Expected entry 1001 not found in result";
   }
   EXPECT_NEAR(m.find("1001")->second, 1, tolerance);
@@ -321,7 +321,7 @@ TEST(DeterministicNoiseSimTest, SimulateAdder4NoNoise2) {
   std::cout << std::setw(2) << nlohmann::basic_json(m) << "\n";
 
   const double tolerance = 1e-10;
-  if (m.count("1001") == 0) {
+  if (!m.contains("1001")) {
     FAIL() << "Expected entry 1001 not found in result";
   }
   EXPECT_NEAR(static_cast<double>(m.find("1001")->second),
@@ -353,7 +353,7 @@ TEST(DeterministicNoiseSimTest, TestSimulateInterface) {
   const auto expectedValues = std::array{616, 1487, 570, 5519};
   const double tolerance = 500;
   for (std::size_t i = 0; i < expectedEntries.size(); ++i) {
-    if (m.count(expectedEntries.at(i)) == 0) {
+    if (!m.contains(expectedEntries.at(i))) {
       FAIL() << "Expected entry " << expectedEntries.at(i)
              << " not found in result";
     }
@@ -381,7 +381,7 @@ TEST(DeterministicNoiseSimTest, TestSimulateInterfaceWithMeasurements) {
   const auto expectedValues = std::array{616, 1487, 570, 5519};
   const double tolerance = 500;
   for (std::size_t i = 0; i < expectedEntries.size(); ++i) {
-    if (m.count(expectedEntries.at(i)) == 0) {
+    if (!m.contains(expectedEntries.at(i))) {
       FAIL() << "Expected entry " << expectedEntries.at(i)
              << " not found in result";
     }
diff --git a/uv.lock b/uv.lock
