Adding the clang format to the CI (#37)

* Applied the clang format to the files we have in `src/`
* No code change

Author: LalehB

.clang-format

@@ -1,7 +1,6 @@
 BasedOnStyle: Google
 IndentWidth: 2
-ColumnLimit: 80
+ColumnLimit: 100
 AllowShortFunctionsOnASingleLine: Empty
 PointerAlignment: Left
-Standard: C++20
 SortIncludes: true

.github/workflows/ci.yml

@@ -1,4 +1,5 @@
 name: ci
+
 on:
   push:
     branches:
@@ -15,8 +16,26 @@ concurrency:
   group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
   cancel-in-progress: true
 
-
 jobs:
+  clang-format-check:
+    name: Clang code formatting
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Checkout repository
+      uses: actions/checkout@v4
+
+    - name: Install clang-format
+      run: |
+        sudo apt-get update
+        sudo apt-get install -y clang-format
+
+    - name: Run clang-format check
+      run: |
+        clang-format --version
+        files=$(git ls-files '*.cc' '*.cpp' '*.h' '*.hpp')
+        [ -z "$files" ] || clang-format --dry-run --Werror $files
+
   build:
     strategy:
       matrix:
@@ -35,5 +54,22 @@ jobs:
         disk-cache: ${{ github.workflow }}
         repository-cache: true
 
+    - name: Install clang-format (Linux)
+      if: runner.os == 'Linux'
+      run: |
+        sudo apt-get update
+        sudo apt-get install -y clang-format
+
+    - name: Install clang-format (macOS)
+      if: runner.os == 'macOS'
+      run: |
+        brew install clang-format
+
+    - name: Check formatting (redundant but allowed)
+      run: |
+        clang-format --version
+        files=$(git ls-files '*.cc' '*.cpp' '*.h' '*.hpp')
+        [ -z "$files" ] || clang-format --dry-run --Werror $files
+
     - name: Bazel tests
       run: bazel test src:all

src/common.cc

@@ -52,12 +52,10 @@ common::Error::Error(const stim::DemInstruction& error) {
 }
 
 std::string common::Error::str() {
-  return "Error{cost=" + std::to_string(likelihood_cost) +
-         ", symptom=" + symptom.str() + "}";
+  return "Error{cost=" + std::to_string(likelihood_cost) + ", symptom=" + symptom.str() + "}";
 }
 
-std::vector<stim::DemTarget> common::Symptom::as_dem_instruction_targets()
-    const {
+std::vector<stim::DemTarget> common::Symptom::as_dem_instruction_targets() const {
   std::vector<stim::DemTarget> targets;
   for (int d : detectors) {
     targets.push_back(stim::DemTarget::relative_detector_id(d));
@@ -72,8 +70,7 @@ std::vector<stim::DemTarget> common::Symptom::as_dem_instruction_targets()
   return targets;
 }
 
-stim::DetectorErrorModel common::merge_identical_errors(
-    const stim::DetectorErrorModel& dem) {
+stim::DetectorErrorModel common::merge_identical_errors(const stim::DetectorErrorModel& dem) {
   stim::DetectorErrorModel out_dem;
 
   // Map to track the distinct symptoms
@@ -89,11 +86,9 @@ stim::DetectorErrorModel common::merge_identical_errors(
         // Merge with existing error with the same symptom (if applicable)
         if (errors_by_symptom.find(error.symptom) != errors_by_symptom.end()) {
           double p0 = errors_by_symptom[error.symptom].probability;
-          error.probability =
-              p0 * (1 - error.probability) + (1 - p0) * error.probability;
+          error.probability = p0 * (1 - error.probability) + (1 - p0) * error.probability;
         }
-        error.likelihood_cost =
-            -1 * std::log(error.probability / (1 - error.probability));
+        error.likelihood_cost = -1 * std::log(error.probability / (1 - error.probability));
         errors_by_symptom[error.symptom] = error;
         break;
       }
@@ -106,9 +101,9 @@ stim::DetectorErrorModel common::merge_identical_errors(
     }
   }
   for (const auto& it : errors_by_symptom) {
-    out_dem.append_error_instruction(
-        it.second.probability, it.second.symptom.as_dem_instruction_targets(),
-        /*tag=*/"");
+    out_dem.append_error_instruction(it.second.probability,
+                                     it.second.symptom.as_dem_instruction_targets(),
+                                     /*tag=*/"");
   }
   return out_dem;
 }
@@ -136,19 +131,17 @@ stim::DetectorErrorModel common::remove_zero_probability_errors(
   return out_dem;
 }
 
-stim::DetectorErrorModel common::dem_from_counts(
-    stim::DetectorErrorModel& orig_dem, const std::vector<size_t>& error_counts,
-    size_t num_shots) {
+stim::DetectorErrorModel common::dem_from_counts(stim::DetectorErrorModel& orig_dem,
+                                                 const std::vector<size_t>& error_counts,
+                                                 size_t num_shots) {
   if (orig_dem.count_errors() != error_counts.size()) {
     throw std::invalid_argument(
         "Error hits array must be the same size as the number of errors in the "
         "original DEM.");
   }
 
-  for (const stim::DemInstruction& instruction :
-       orig_dem.flattened().instructions) {
-    if (instruction.type == stim::DemInstructionType::DEM_ERROR &&
-        instruction.arg_data[0] == 0) {
+  for (const stim::DemInstruction& instruction : orig_dem.flattened().instructions) {
+    if (instruction.type == stim::DemInstructionType::DEM_ERROR && instruction.arg_data[0] == 0) {
       throw std::invalid_argument(
           "dem_from_counts requires DEMs without zero-probability errors. Use"
           " remove_zero_probability_errors first.");
@@ -157,17 +150,14 @@ stim::DetectorErrorModel common::dem_from_counts(
 
   stim::DetectorErrorModel out_dem;
   size_t ei = 0;
-  for (const stim::DemInstruction& instruction :
-       orig_dem.flattened().instructions) {
+  for (const stim::DemInstruction& instruction : orig_dem.flattened().instructions) {
     switch (instruction.type) {
       case stim::DemInstructionType::DEM_SHIFT_DETECTORS:
         assert(false && "unreachable");
         break;
       case stim::DemInstructionType::DEM_ERROR: {
-        double est_probability =
-            double(error_counts.at(ei)) / double(num_shots);
-        out_dem.append_error_instruction(est_probability,
-                                         instruction.target_data, /*tag=*/"");
+        double est_probability = double(error_counts.at(ei)) / double(num_shots);
+        out_dem.append_error_instruction(est_probability, instruction.target_data, /*tag=*/"");
         ++ei;
         break;
       }

src/common.h

@@ -51,11 +51,9 @@ struct Error {
   Symptom symptom;
   std::vector<bool> dets_array;
   Error() = default;
-  Error(double likelihood_cost, std::vector<int>& detectors,
-        ObservablesMask observables, std::vector<bool>& dets_array)
-      : likelihood_cost(likelihood_cost),
-        symptom{detectors, observables},
-        dets_array(dets_array) {}
+  Error(double likelihood_cost, std::vector<int>& detectors, ObservablesMask observables,
+        std::vector<bool>& dets_array)
+      : likelihood_cost(likelihood_cost), symptom{detectors, observables}, dets_array(dets_array) {}
   Error(double likelihood_cost, double probability, std::vector<int>& detectors,
         ObservablesMask observables, std::vector<bool>& dets_array)
       : likelihood_cost(likelihood_cost),
@@ -68,21 +66,18 @@ struct Error {
 
 // Makes a new (flattened) dem where identical error mechanisms have been
 // merged.
-stim::DetectorErrorModel merge_identical_errors(
-    const stim::DetectorErrorModel& dem);
+stim::DetectorErrorModel merge_identical_errors(const stim::DetectorErrorModel& dem);
 
 // Returns a copy of the given error model with any zero-probability DEM_ERROR
 // instructions removed.
-stim::DetectorErrorModel remove_zero_probability_errors(
-    const stim::DetectorErrorModel& dem);
+stim::DetectorErrorModel remove_zero_probability_errors(const stim::DetectorErrorModel& dem);
 
 // Makes a new dem where the probabilities of errors are estimated from the
 // fraction of shots they were used in.
 // Throws std::invalid_argument if `orig_dem` contains zero-probability errors;
 // call remove_zero_probability_errors first.
-stim::DetectorErrorModel dem_from_counts(
-    stim::DetectorErrorModel& orig_dem, const std::vector<size_t>& error_counts,
-    size_t num_shots);
+stim::DetectorErrorModel dem_from_counts(stim::DetectorErrorModel& orig_dem,
+                                         const std::vector<size_t>& error_counts, size_t num_shots);
 
 }  // namespace common
 

src/common.pybind.h

@@ -32,8 +32,7 @@ void add_common_module(py::module &root) {
 
   py::class_<common::Symptom>(m, "Symptom")
       .def(py::init<std::vector<int>, common::ObservablesMask>(),
-           py::arg("detectors") = std::vector<int>(),
-           py::arg("observables") = 0)
+           py::arg("detectors") = std::vector<int>(), py::arg("observables") = 0)
       .def_readwrite("detectors", &common::Symptom::detectors)
       .def_readwrite("observables", &common::Symptom::observables)
       .def("__str__", &common::Symptom::str)
@@ -51,25 +50,22 @@ void add_common_module(py::module &root) {
       .def_readwrite("symptom", &common::Error::symptom)
       .def("__str__", &common::Error::str)
       .def(py::init<>())
-      .def(py::init<double, std::vector<int> &, common::ObservablesMask,
-                    std::vector<bool> &>(),
-           py::arg("likelihood_cost"), py::arg("detectors"),
-           py::arg("observables"), py::arg("dets_array"))
+      .def(py::init<double, std::vector<int> &, common::ObservablesMask, std::vector<bool> &>(),
+           py::arg("likelihood_cost"), py::arg("detectors"), py::arg("observables"),
+           py::arg("dets_array"))
       .def(py::init<double, double, std::vector<int> &, common::ObservablesMask,
                     std::vector<bool> &>(),
-           py::arg("likelihood_cost"), py::arg("probability"),
-           py::arg("detectors"), py::arg("observables"), py::arg("dets_array"))
+           py::arg("likelihood_cost"), py::arg("probability"), py::arg("detectors"),
+           py::arg("observables"), py::arg("dets_array"))
       .def(py::init([](stim_pybind::ExposedDemInstruction edi) {
              return new common::Error(edi.as_dem_instruction());
            }),
            py::arg("error"));
 
-  m.def("merge_identical_errors", &common::merge_identical_errors,
-        py::arg("dem"));
-  m.def("remove_zero_probability_errors",
-        &common::remove_zero_probability_errors, py::arg("dem"));
-  m.def("dem_from_counts", &common::dem_from_counts, py::arg("orig_dem"),
-        py::arg("error_counts"), py::arg("num_shots"));
+  m.def("merge_identical_errors", &common::merge_identical_errors, py::arg("dem"));
+  m.def("remove_zero_probability_errors", &common::remove_zero_probability_errors, py::arg("dem"));
+  m.def("dem_from_counts", &common::dem_from_counts, py::arg("orig_dem"), py::arg("error_counts"),
+        py::arg("num_shots"));
 }
 
 #endif

src/common.test.cc

@@ -38,9 +38,7 @@ TEST(common, DemFromCountsRejectsZeroProbabilityErrors) {
 
   std::vector<size_t> counts{1, 7, 4};
   size_t num_shots = 10;
-  EXPECT_THROW({
-    common::dem_from_counts(dem, counts, num_shots);
-  }, std::invalid_argument);
+  EXPECT_THROW({ common::dem_from_counts(dem, counts, num_shots); }, std::invalid_argument);
 
   stim::DetectorErrorModel cleaned = common::remove_zero_probability_errors(dem);
   stim::DetectorErrorModel out_dem =
@@ -50,11 +48,9 @@ TEST(common, DemFromCountsRejectsZeroProbabilityErrors) {
   ASSERT_EQ(out_dem.count_errors(), 2);
   ASSERT_GE(flat.instructions.size(), 2);
 
-  EXPECT_EQ(flat.instructions[0].type,
-            stim::DemInstructionType::DEM_ERROR);
+  EXPECT_EQ(flat.instructions[0].type, stim::DemInstructionType::DEM_ERROR);
   EXPECT_NEAR(flat.instructions[0].arg_data[0], 0.1, 1e-9);
-  ASSERT_EQ(flat.instructions[1].type,
-            stim::DemInstructionType::DEM_ERROR);
+  ASSERT_EQ(flat.instructions[1].type, stim::DemInstructionType::DEM_ERROR);
   EXPECT_NEAR(flat.instructions[1].arg_data[0], 0.4, 1e-9);
 }
 
@@ -68,18 +64,15 @@ TEST(common, DemFromCountsSimpleTwoErrors) {
 
   std::vector<size_t> counts{5, 7};
   size_t num_shots = 20;
-  stim::DetectorErrorModel out_dem =
-      common::dem_from_counts(dem, counts, num_shots);
+  stim::DetectorErrorModel out_dem = common::dem_from_counts(dem, counts, num_shots);
 
   auto flat = out_dem.flattened();
   ASSERT_EQ(out_dem.count_errors(), 2);
 
   ASSERT_GE(flat.instructions.size(), 2);
-  EXPECT_EQ(flat.instructions[0].type,
-            stim::DemInstructionType::DEM_ERROR);
+  EXPECT_EQ(flat.instructions[0].type, stim::DemInstructionType::DEM_ERROR);
   EXPECT_NEAR(flat.instructions[0].arg_data[0], 0.25, 1e-9);
-  EXPECT_EQ(flat.instructions[1].type,
-            stim::DemInstructionType::DEM_ERROR);
+  EXPECT_EQ(flat.instructions[1].type, stim::DemInstructionType::DEM_ERROR);
   EXPECT_NEAR(flat.instructions[1].arg_data[0], 0.35, 1e-9);
 }
 
@@ -93,15 +86,12 @@ TEST(common, RemoveZeroProbabilityErrors) {
         detector(0, 0, 0) D2
       )DEM");
 
-  stim::DetectorErrorModel cleaned =
-      common::remove_zero_probability_errors(dem);
+  stim::DetectorErrorModel cleaned = common::remove_zero_probability_errors(dem);
 
   EXPECT_EQ(cleaned.count_errors(), 2);
   auto flat = cleaned.flattened();
-  ASSERT_EQ(flat.instructions[0].type,
-            stim::DemInstructionType::DEM_ERROR);
+  ASSERT_EQ(flat.instructions[0].type, stim::DemInstructionType::DEM_ERROR);
   EXPECT_NEAR(flat.instructions[0].arg_data[0], 0.1, 1e-9);
-  ASSERT_EQ(flat.instructions[1].type,
-            stim::DemInstructionType::DEM_ERROR);
+  ASSERT_EQ(flat.instructions[1].type, stim::DemInstructionType::DEM_ERROR);
   EXPECT_NEAR(flat.instructions[1].arg_data[0], 0.2, 1e-9);
 }