actually use the new matrix logging stuff
diff --git a/frc971/control_loops/drivetrain/drivetrain.cc b/frc971/control_loops/drivetrain/drivetrain.cc
index f7affb9..9f3b94d 100644
--- a/frc971/control_loops/drivetrain/drivetrain.cc
+++ b/frc971/control_loops/drivetrain/drivetrain.cc
@@ -126,6 +126,8 @@
       }
       loop_->UpdateObserver();
     }
+    ::Eigen::Matrix<double, 4, 1> E = loop_->R - loop_->X_hat;
+    LOG_MATRIX(DEBUG, "E", E);
   }
 
   double GetEstimatedRobotSpeed() {
@@ -148,10 +150,6 @@
       output->right_voltage = loop_->U(1, 0);
     }
   }
-  void PrintMotors() const {
-    ::Eigen::Matrix<double, 4, 1> E = loop_->R - loop_->X_hat;
-    LOG_MATRIX(DEBUG, "E", E);
-  }
 
  private:
   ::std::unique_ptr<StateFeedbackLoop<4, 2, 2>> loop_;