From 2a1d6d26b9f287379efeb3ed2e0535c02c240636 Mon Sep 17 00:00:00 2001
From: Taekjin LEE <taekjin.lee@tier4.jp>
Date: Mon, 21 Oct 2024 16:17:45 +0900
Subject: [PATCH] perf PR 8751

---
 .../src/path_generator.cpp                    | 30 ++++++++++++-------
 1 file changed, 19 insertions(+), 11 deletions(-)

diff --git a/perception/map_based_prediction/src/path_generator.cpp b/perception/map_based_prediction/src/path_generator.cpp
index a7dda00dc4f21..0850c55b3c248 100644
--- a/perception/map_based_prediction/src/path_generator.cpp
+++ b/perception/map_based_prediction/src/path_generator.cpp
@@ -223,16 +223,18 @@ FrenetPath PathGenerator::generateFrenetPath(
 
   path.reserve(static_cast<size_t>(duration / sampling_time_interval_));
   for (double t = 0.0; t <= duration; t += sampling_time_interval_) {
+    const auto t2 = t * t;
+    const auto t3 = t2 * t;
+    const auto t4 = t3 * t;
+    const auto t5 = t4 * t;
     const double current_acc =
       0.0;  // Currently we assume the object is traveling at a constant speed
-    const double d_next_ = current_point.d + current_point.d_vel * t +
-                           current_acc * 2.0 * std::pow(t, 2) + lat_coeff(0) * std::pow(t, 3) +
-                           lat_coeff(1) * std::pow(t, 4) + lat_coeff(2) * std::pow(t, 5);
+    const double d_next_ = current_point.d + current_point.d_vel * t + current_acc * 2.0 * t2 +
+                           lat_coeff(0) * t3 + lat_coeff(1) * t4 + lat_coeff(2) * t5;
     // t > lateral_duration: 0.0, else d_next_
     const double d_next = t > lateral_duration ? 0.0 : d_next_;
-    const double s_next = current_point.s + current_point.s_vel * t +
-                          2.0 * current_acc * std::pow(t, 2) + lon_coeff(0) * std::pow(t, 3) +
-                          lon_coeff(1) * std::pow(t, 4);
+    const double s_next = current_point.s + current_point.s_vel * t + 2.0 * current_acc * t2 +
+                          lon_coeff(0) * t3 + lon_coeff(1) * t4;
     if (s_next > max_length) {
       break;
     }
@@ -265,10 +267,14 @@ Eigen::Vector3d PathGenerator::calcLatCoefficients(
   // b = np.matrix([[xe - self.a0 - self.a1 * T - self.a2 * T**2],
   //                [vxe - self.a1 - 2 * self.a2 * T],
   //                [axe - 2 * self.a2]])
+  const auto T2 = T * T;
+  const auto T3 = T2 * T;
+  const auto T4 = T3 * T;
+  const auto T5 = T4 * T;
+
   Eigen::Matrix3d A_lat_inv;
-  A_lat_inv << 10 / std::pow(T, 3), -4 / std::pow(T, 2), 1 / (2 * T), -15 / std::pow(T, 4),
-    7 / std::pow(T, 3), -1 / std::pow(T, 2), 6 / std::pow(T, 5), -3 / std::pow(T, 4),
-    1 / (2 * std::pow(T, 3));
+  A_lat_inv << 10 / T3, -4 / T2, 1 / (2 * T), -15 / T4, 7 / T3, -1 / T2, 6 / T5, -3 / T4,
+    1 / (2 * T3);
   Eigen::Vector3d b_lat;
   b_lat[0] = target_point.d - current_point.d - current_point.d_vel * T;
   b_lat[1] = target_point.d_vel - current_point.d_vel;
@@ -286,9 +292,11 @@ Eigen::Vector2d PathGenerator::calcLonCoefficients(
   //                         [-1/(2*T**3), 1/(4*T**2)]])
   // b = np.matrix([[vxe - self.a1 - 2 * self.a2 * T],
   //               [axe - 2 * self.a2]])
+  const auto T2 = T * T;
+  const auto T3 = T2 * T;
+
   Eigen::Matrix2d A_lon_inv;
-  A_lon_inv << 1 / std::pow(T, 2), -1 / (3 * T), -1 / (2 * std::pow(T, 3)),
-    1 / (4 * std::pow(T, 2));
+  A_lon_inv << 1 / T2, -1 / (3 * T), -1 / (2 * T3), 1 / (4 * T2);
   Eigen::Vector2d b_lon;
   b_lon[0] = target_point.s_vel - current_point.s_vel;
   b_lon[1] = 0.0;