Make readability-function-cognitive-complexity threshold more strict

Author: aobolensk

.clang-tidy

@@ -85,7 +85,8 @@ CheckOptions:
     value:           lower_case
   - key:             readability-identifier-naming.IgnoreMainLikeFunctions
     value:           1
+  # Functions with scores beyond 15 are typically flagged as potentially problematic (empirically)
   - key:             readability-function-cognitive-complexity.Threshold
-    value:           25  # default: 25
+    value:           15  # default: 25
   - key: misc-include-cleaner.IgnoreHeaders
     value: '(opencv2/.*|__chrono/.*)'

tasks/mpi/example/src/ops_mpi.cpp

@@ -25,29 +25,37 @@ bool nesterov_a_test_task_mpi::TestTaskMPI::ValidationImpl() {
 }
 
 bool nesterov_a_test_task_mpi::TestTaskMPI::RunImpl() {
-  int rank = -1;
-  MPI_Comm_rank(MPI_COMM_WORLD, &rank);
-  if (rank == 0) {
-    // Multiply matrices
-    for (int i = 0; i < rc_size_; ++i) {
-      for (int j = 0; j < rc_size_; ++j) {
-        for (int k = 0; k < rc_size_; ++k) {
-          output_[(i * rc_size_) + j] += input_[(i * rc_size_) + k] * input_[(k * rc_size_) + j];
-        }
-      }
-    }
+  MultiplyMatrixBasedOnRank();
+  return true;
+}
+
+void nesterov_a_test_task_mpi::TestTaskMPI::MultiplyMatrixBasedOnRank() {
+  if (world_.rank() == 0) {
+    MultiplyRowMajor();
   } else {
-    // Multiply matrices
+    MultiplyColumnMajor();
+  }
+  world_.barrier();
+}
+
+void nesterov_a_test_task_mpi::TestTaskMPI::MultiplyRowMajor() {
+  for (int i = 0; i < rc_size_; ++i) {
     for (int j = 0; j < rc_size_; ++j) {
       for (int k = 0; k < rc_size_; ++k) {
-        for (int i = 0; i < rc_size_; ++i) {
-          output_[(i * rc_size_) + j] += input_[(i * rc_size_) + k] * input_[(k * rc_size_) + j];
-        }
+        output_[(i * rc_size_) + j] += input_[(i * rc_size_) + k] * input_[(k * rc_size_) + j];
+      }
+    }
+  }
+}
+
+void nesterov_a_test_task_mpi::TestTaskMPI::MultiplyColumnMajor() {
+  for (int j = 0; j < rc_size_; ++j) {
+    for (int k = 0; k < rc_size_; ++k) {
+      for (int i = 0; i < rc_size_; ++i) {
+        output_[(i * rc_size_) + j] += input_[(i * rc_size_) + k] * input_[(k * rc_size_) + j];
       }
     }
   }
-  MPI_Barrier(MPI_COMM_WORLD);
-  return true;
 }
 
 bool nesterov_a_test_task_mpi::TestTaskMPI::PostProcessingImpl() {