src: avoid use of double precision pow & exp

saves around 5KB flash on px4-fmu-v5

src/drivers/uwb/uwb_sr150/uwb_sr150.cpp

@@ -587,18 +587,18 @@ UWB_POS_ERROR_CODES UWB_SR150::localization()
 	/* Writing values resulting from least square error method (A_trans*A*x = A_trans*r; row 0 was used to remove x^2,y^2,z^2 entries => index starts at 1) */
 	for (int i = 1; i < no_valid_distances; i++) {
 		/* Matrix (needed to be multiplied with 2, afterwards) */
-		M_11 += (int64_t)pow((int64_t)(anchor_pos[i].x - anchor_pos[0].x), 2);
+		M_11 += sq((int64_t)(anchor_pos[i].x - anchor_pos[0].x));
 		M_12 += (int64_t)((int64_t)(anchor_pos[i].x - anchor_pos[0].x) * (int64_t)(anchor_pos[i].y - anchor_pos[0].y));
 		M_13 += (int64_t)((int64_t)(anchor_pos[i].x - anchor_pos[0].x) * (int64_t)(anchor_pos[i].z - anchor_pos[0].z));
-		M_22 += (int64_t)pow((int64_t)(anchor_pos[i].y - anchor_pos[0].y), 2);
+		M_22 += sq((int64_t)(anchor_pos[i].y - anchor_pos[0].y));
 		M_23 += (int64_t)((int64_t)(anchor_pos[i].y - anchor_pos[0].y) * (int64_t)(anchor_pos[i].z - anchor_pos[0].z));
-		M_33 += (int64_t)pow((int64_t)(anchor_pos[i].z - anchor_pos[0].z), 2);
+		M_33 += sq((int64_t)(anchor_pos[i].z - anchor_pos[0].z));
 
 		/* Vector */
-		temp = (int64_t)((int64_t)pow(distances_cm[0], 2) - (int64_t)pow(distances_cm[i], 2)
-				 + (int64_t)pow(anchor_pos[i].x, 2) + (int64_t)pow(anchor_pos[i].y, 2)
-				 + (int64_t)pow(anchor_pos[i].z, 2) - (int64_t)pow(anchor_pos[0].x, 2)
-				 - (int64_t)pow(anchor_pos[0].y, 2) - (int64_t)pow(anchor_pos[0].z, 2));
+		temp = sq(distances_cm[0]) - sq(distances_cm[i])
+		       + sq(anchor_pos[i].x) + sq(anchor_pos[i].y)
+		       + sq(anchor_pos[i].z) - sq(anchor_pos[0].x)
+		       - sq(anchor_pos[0].y) - sq(anchor_pos[0].z);
 
 		b[0] += (int64_t)((int64_t)(anchor_pos[i].x - anchor_pos[0].x) * temp);
 		b[1] += (int64_t)((int64_t)(anchor_pos[i].y - anchor_pos[0].y) * temp);

src/drivers/uwb/uwb_sr150/uwb_sr150.h

@@ -163,6 +163,8 @@ public:
 	void run() override;
 
 private:
+	static constexpr int64_t sq(int64_t x) { return x * x; }
+
 	void parameters_update();
 
 	void grid_info_read(position_t *grid);

src/lib/pid_design/pid_design.hpp

@@ -82,7 +82,7 @@ inline matrix::Vector3f computePidGmvc(const matrix::Vector3f &num, const matrix
 	const float rho = dt / sigma;
 	const float mu = 0.25f * (1.f - delta) + 0.51f * delta; // mu is in the interval [0.25 0.51]
 	const float p1 = -2.f * expf(-rho / (2.f * mu)) * cosf(sqrtf(4.f * mu - 1.f) * rho / (2.f * mu));
-	const float p2 = exp(-rho / mu);
+	const float p2 = expf(-rho / mu);
 	const float e1 = -a1 + p1 + 1.f;
 	const float f0 = -a1 * e1 + a1 - a2 + e1 + p2;
 	const float f1 = a1 * e1 - a2 * e1 + a2;

src/modules/flight_mode_manager/tasks/AutoFollowTarget/follow_target_estimator/TargetEstimator.cpp

@@ -193,7 +193,7 @@ void TargetEstimator::update_filter_gains(filter_gains_s &filter_gains) const
 	// The "G" gain is equivalent to "(1-responsiveness)", but beta is required for H and K gains
 	// From alpha-beta-gamma filter equations: G = 1-beta^3
 	// Therefore: beta = (1-Gp)^(1/3) = (1-(1-responsiveness))^(1/3) = (r)^(1/3)
-	const float beta_p = pow((filter_gains.responsiveness), 1.0f / 3.0f);
+	const float beta_p = powf((filter_gains.responsiveness), 1.0f / 3.0f);
 	const float beta_v = 0.9f * beta_p; // velocity fusion gain is slightly lower. TODO: individual parameter?
 
 	// Estimator gains for horizontal position update