PWR037: Add benchmark

Benchmark/src/CMakeLists.txt

@@ -1,6 +1,7 @@
 add_benchmark(PWR003)
 add_benchmark(PWR022)
 add_benchmark(PWR032)
+add_benchmark(PWR037)
 add_benchmark(PWR039)
 add_benchmark(PWR043)
 add_benchmark(PWR062)

Benchmark/src/PWR037.cpp

@@ -0,0 +1,54 @@
+#include "Benchmark.h"
+
+// Forward-declare the functions to benchmark
+extern "C" {
+void compute_damped_sinusoid(const int n, const double *timesteps,
+                             const double amplitude,
+                             const double angularFrequency,
+                             const double decayRate, const double phaseShift,
+                             double *results);
+void compute_damped_sinusoid_improved(const int n, const double *timesteps,
+                                      const double amplitude,
+                                      const double angularFrequency,
+                                      const double decayRate,
+                                      const double phaseShift, double *results);
+}
+
+// Size adjusted to fit execution on micro-seconds
+constexpr int N = 1024 * 1024;
+constexpr double AMPLITUDE = 1.0;
+constexpr double ANGULAR_FREQUENCY = 2.0;
+constexpr double DECAY_RATE = 0.5;
+constexpr double PHASE_SHIFT = 3.141592653589793 / 4;
+
+#if OCB_ENABLE_C
+
+static void CExampleBench(benchmark::State &state) {
+  const auto timesteps = OpenCatalog::CreateRandomVector<double>(N, 0.0, 10.0);
+  auto results = OpenCatalog::CreateUninitializedVector<double>(N);
+
+  for (auto _ : state) {
+    compute_damped_sinusoid(N, timesteps.data(), AMPLITUDE, ANGULAR_FREQUENCY,
+                            DECAY_RATE, PHASE_SHIFT, results.data());
+    benchmark::DoNotOptimize(results);
+  }
+}
+
+static void CImprovedBench(benchmark::State &state) {
+  const auto timesteps = OpenCatalog::CreateRandomVector<double>(N, 0.0, 10.0);
+  auto results = OpenCatalog::CreateUninitializedVector<double>(N);
+
+  for (auto _ : state) {
+    compute_damped_sinusoid_improved(N, timesteps.data(), AMPLITUDE,
+                                     ANGULAR_FREQUENCY, DECAY_RATE, PHASE_SHIFT,
+                                     results.data());
+    benchmark::DoNotOptimize(results);
+  }
+}
+
+// A performance impact is expected when performing higher-precision
+// calculations
+OC_BENCHMARK("PWR037 C Example", CExampleBench);
+OC_BENCHMARK("PWR037 C Fixed", CImprovedBench);
+
+#endif

Checks/PWR037/benchmark/example.c

@@ -0,0 +1,17 @@
+// PWR037: Potential precision loss in call to mathematical function
+
+#include <math.h>
+
+// https://en.wikipedia.org/wiki/Damping#Damped_sine_wave
+void compute_damped_sinusoid(const int n, const double *timesteps,
+                             const double amplitude,
+                             const double angularFrequency,
+                             const double decayRate, const double phaseShift,
+                             double *results) {
+
+  for (int i = 0; i < n; ++i) {
+    double exponentialDecay = expf(-decayRate * timesteps[i]);
+    double angle = angularFrequency * timesteps[i] + phaseShift;
+    results[i] = amplitude * exponentialDecay * cosf(angle);
+  }
+}

Checks/PWR037/benchmark/solution.c

@@ -0,0 +1,18 @@
+// PWR037: Potential precision loss in call to mathematical function
+
+#include <math.h>
+
+// https://en.wikipedia.org/wiki/Damping#Damped_sine_wave
+void compute_damped_sinusoid_improved(const int n, const double *timesteps,
+                                      const double amplitude,
+                                      const double angularFrequency,
+                                      const double decayRate,
+                                      const double phaseShift,
+                                      double *results) {
+
+  for (int i = 0; i < n; ++i) {
+    double exponentialDecay = exp(-decayRate * timesteps[i]);
+    double angle = angularFrequency * timesteps[i] + phaseShift;
+    results[i] = amplitude * exponentialDecay * cos(angle);
+  }
+}