whole_func_string: function madgwickAHRSupdateIMU(gx, gy, gz, ax, ay, az) {
      let recipNorm;
      let s0, s1, s2, s3;
      let qDot1, qDot2, qDot3, qDot4;
      let v2q0, v2q1, v2q2, v2q3, v4q0, v4q1, v4q2, v8q1, v8q2, q0q0, q1q1, q2q2, q3q3;
  
      // Rate of change of quaternion from gyroscope
      qDot1 = 0.5 * (-q1 * gx - q2 * gy - q3 * gz);
      qDot2 = 0.5 * (q0 * gx + q2 * gz - q3 * gy);
      qDot3 = 0.5 * (q0 * gy - q1 * gz + q3 * gx);
      qDot4 = 0.5 * (q0 * gz + q1 * gy - q2 * gx);
  
      // Compute feedback only if accelerometer measurement valid (avoids NaN in accelerometer normalisation)
      if (!(ax === 0.0 && ay === 0.0 && az === 0.0)) {
        // Normalise accelerometer measurement
        recipNorm = (ax * ax + ay * ay + az * az) ** -0.5;
        ax *= recipNorm;
        ay *= recipNorm;
        az *= recipNorm;
  
        // Auxiliary variables to avoid repeated arithmetic
        v2q0 = 2.0 * q0;
        v2q1 = 2.0 * q1;
        v2q2 = 2.0 * q2;
        v2q3 = 2.0 * q3;
        v4q0 = 4.0 * q0;
        v4q1 = 4.0 * q1;
        v4q2 = 4.0 * q2;
        v8q1 = 8.0 * q1;
        v8q2 = 8.0 * q2;
        q0q0 = q0 * q0;
        q1q1 = q1 * q1;
        q2q2 = q2 * q2;
        q3q3 = q3 * q3;
  
        // Gradient decent algorithm corrective step
        s0 = v4q0 * q2q2 + v2q2 * ax + v4q0 * q1q1 - v2q1 * ay;
        s1 = v4q1 * q3q3 - v2q3 * ax + 4.0 * q0q0 * q1 - v2q0 * ay - v4q1 + v8q1 * q1q1 + v8q1 * q2q2 + v4q1 * az;
        s2 = 4.0 * q0q0 * q2 + v2q0 * ax + v4q2 * q3q3 - v2q3 * ay - v4q2 + v8q2 * q1q1 + v8q2 * q2q2 + v4q2 * az;
        s3 = 4.0 * q1q1 * q3 - v2q1 * ax + 4.0 * q2q2 * q3 - v2q2 * ay;
        recipNorm = (s0 * s0 + s1 * s1 + s2 * s2 + s3 * s3) ** -0.5; // normalise step magnitude
        s0 *= recipNorm;
        s1 *= recipNorm;
        s2 *= recipNorm;
        s3 *= recipNorm;
  
        // Apply feedback step
        qDot1 -= beta * s0;
        qDot2 -= beta * s1;
        qDot3 -= beta * s2;
        qDot4 -= beta * s3;
      }
  
      // Integrate rate of change of quaternion to yield quaternion
      q0 += qDot1 * recipSampleFreq;
      q1 += qDot2 * recipSampleFreq;
      q2 += qDot3 * recipSampleFreq;
      q3 += qDot4 * recipSampleFreq;
  
      // Normalise quaternion
      recipNorm = (q0 * q0 + q1 * q1 + q2 * q2 + q3 * q3) ** -0.5;
      q0 *= recipNorm;
      q1 *= recipNorm;
      q2 *= recipNorm;
      q3 *= recipNorm;
    }
func_code_string: function madgwickAHRSupdateIMU(gx, gy, gz, ax, ay, az) {
      let recipNorm;
      let s0, s1, s2, s3;
      let qDot1, qDot2, qDot3, qDot4;
      let v2q0, v2q1, v2q2, v2q3, v4q0, v4q1, v4q2, v8q1, v8q2, q0q0, q1q1, q2q2, q3q3;
  
      // Rate of change of quaternion from gyroscope
      qDot1 = 0.5 * (-q1 * gx - q2 * gy - q3 * gz);
      qDot2 = 0.5 * (q0 * gx + q2 * gz - q3 * gy);
      qDot3 = 0.5 * (q0 * gy - q1 * gz + q3 * gx);
      qDot4 = 0.5 * (q0 * gz + q1 * gy - q2 * gx);
  
      // Compute feedback only if accelerometer measurement valid (avoids NaN in accelerometer normalisation)
      if (!(ax === 0.0 && ay === 0.0 && az === 0.0)) {
        // Normalise accelerometer measurement
        recipNorm = (ax * ax + ay * ay + az * az) ** -0.5;
        ax *= recipNorm;
        ay *= recipNorm;
        az *= recipNorm;
  
        // Auxiliary variables to avoid repeated arithmetic
        v2q0 = 2.0 * q0;
        v2q1 = 2.0 * q1;
        v2q2 = 2.0 * q2;
        v2q3 = 2.0 * q3;
        v4q0 = 4.0 * q0;
        v4q1 = 4.0 * q1;
        v4q2 = 4.0 * q2;
        v8q1 = 8.0 * q1;
        v8q2 = 8.0 * q2;
        q0q0 = q0 * q0;
        q1q1 = q1 * q1;
        q2q2 = q2 * q2;
        q3q3 = q3 * q3;
  
        // Gradient decent algorithm corrective step
        s0 = v4q0 * q2q2 + v2q2 * ax + v4q0 * q1q1 - v2q1 * ay;
        s1 = v4q1 * q3q3 - v2q3 * ax + 4.0 * q0q0 * q1 - v2q0 * ay - v4q1 + v8q1 * q1q1 + v8q1 * q2q2 + v4q1 * az;
        s2 = 4.0 * q0q0 * q2 + v2q0 * ax + v4q2 * q3q3 - v2q3 * ay - v4q2 + v8q2 * q1q1 + v8q2 * q2q2 + v4q2 * az;
        s3 = 4.0 * q1q1 * q3 - v2q1 * ax + 4.0 * q2q2 * q3 - v2q2 * ay;
        recipNorm = (s0 * s0 + s1 * s1 + s2 * s2 + s3 * s3) ** -0.5; // normalise step magnitude
        s0 *= recipNorm;
        s1 *= recipNorm;
        s2 *= recipNorm;
        s3 *= recipNorm;
  
        // Apply feedback step
        qDot1 -= beta * s0;
        qDot2 -= beta * s1;
        qDot3 -= beta * s2;
        qDot4 -= beta * s3;
      }
  
      // Integrate rate of change of quaternion to yield quaternion
      q0 += qDot1 * recipSampleFreq;
      q1 += qDot2 * recipSampleFreq;
      q2 += qDot3 * recipSampleFreq;
      q3 += qDot4 * recipSampleFreq;
  
      // Normalise quaternion
      recipNorm = (q0 * q0 + q1 * q1 + q2 * q2 + q3 * q3) ** -0.5;
      q0 *= recipNorm;
      q1 *= recipNorm;
      q2 *= recipNorm;
      q3 *= recipNorm;
    }
func_documentation_string: --------------------------------------------------------------------------------------------------- IMU algorithm update