[wpimath] Clean up Eigen usage

* Replace Matrix<> with Vector<> where vectors are explicitly intended.
  I found these via `rg "Eigen::Matrix<double, \w+, 1>"`.
* Pass all Eigen matrices by const reference. I found these via `rg
  "\(Eigen"` on main (the initializer list constructors make more false
  positives).
* Replace MakeMatrix() and operator<< usage with initializer list
  constructors. I found these via `rg MakeMatrix` and `rg "<<"`
  respectively.
* Deprecate MakeMatrix()

wpilibc/src/main/native/include/frc/simulation/DifferentialDrivetrainSim.h

@@ -80,7 +80,7 @@ class DifferentialDrivetrainSim {
    * @param maxVoltage The maximum voltage.
    * @return The normalized input.
    */
-  Eigen::Matrix<double, 2, 1> ClampInput(Eigen::Matrix<double, 2, 1> u);
+  Eigen::Vector<double, 2> ClampInput(const Eigen::Vector<double, 2>& u);
 
   /**
    * Sets the applied voltage to the drivetrain. Note that positive voltage must
@@ -178,7 +178,7 @@ class DifferentialDrivetrainSim {
    *
    * @param state The state.
    */
-  void SetState(const Eigen::Matrix<double, 7, 1>& state);
+  void SetState(const Eigen::Vector<double, 7>& state);
 
   /**
    * Sets the system pose.
@@ -187,8 +187,8 @@ class DifferentialDrivetrainSim {
    */
   void SetPose(const frc::Pose2d& pose);
 
-  Eigen::Matrix<double, 7, 1> Dynamics(const Eigen::Matrix<double, 7, 1>& x,
-                                       const Eigen::Matrix<double, 2, 1>& u);
+  Eigen::Vector<double, 7> Dynamics(const Eigen::Vector<double, 7>& x,
+                                    const Eigen::Vector<double, 2>& u);
 
   class State {
    public:
@@ -295,7 +295,7 @@ class DifferentialDrivetrainSim {
   /**
    * Returns the current output vector y.
    */
-  Eigen::Matrix<double, 7, 1> GetOutput() const;
+  Eigen::Vector<double, 7> GetOutput() const;
 
   /**
    * Returns an element of the state vector. Note that this will not include
@@ -308,7 +308,7 @@ class DifferentialDrivetrainSim {
   /**
    * Returns the current state vector x. Note that this will not include noise!
    */
-  Eigen::Matrix<double, 7, 1> GetState() const;
+  Eigen::Vector<double, 7> GetState() const;
 
   LinearSystem<2, 2, 2> m_plant;
   units::meter_t m_rb;
@@ -319,9 +319,9 @@ class DifferentialDrivetrainSim {
   double m_originalGearing;
   double m_currentGearing;
 
-  Eigen::Matrix<double, 7, 1> m_x;
-  Eigen::Matrix<double, 2, 1> m_u;
-  Eigen::Matrix<double, 7, 1> m_y;
+  Eigen::Vector<double, 7> m_x;
+  Eigen::Vector<double, 2> m_u;
+  Eigen::Vector<double, 7> m_y;
   std::array<double, 7> m_measurementStdDevs;
 };
 }  // namespace frc::sim

wpilibc/src/main/native/include/frc/simulation/ElevatorSim.h

@@ -123,9 +123,9 @@ class ElevatorSim : public LinearSystemSim<2, 1, 1> {
    * @param u           The system inputs (voltage).
    * @param dt          The time difference between controller updates.
    */
-  Eigen::Matrix<double, 2, 1> UpdateX(
-      const Eigen::Matrix<double, 2, 1>& currentXhat,
-      const Eigen::Matrix<double, 1, 1>& u, units::second_t dt) override;
+  Eigen::Vector<double, 2> UpdateX(const Eigen::Vector<double, 2>& currentXhat,
+                                   const Eigen::Vector<double, 1>& u,
+                                   units::second_t dt) override;
 
  private:
   DCMotor m_gearbox;

wpilibc/src/main/native/include/frc/simulation/LinearSystemSim.h

@@ -40,9 +40,9 @@ class LinearSystemSim {
       const LinearSystem<States, Inputs, Outputs>& system,
       const std::array<double, Outputs>& measurementStdDevs = {})
       : m_plant(system), m_measurementStdDevs(measurementStdDevs) {
-    m_x = Eigen::Matrix<double, States, 1>::Zero();
-    m_y = Eigen::Matrix<double, Outputs, 1>::Zero();
-    m_u = Eigen::Matrix<double, Inputs, 1>::Zero();
+    m_x = Eigen::Vector<double, States>::Zero();
+    m_y = Eigen::Vector<double, Outputs>::Zero();
+    m_u = Eigen::Vector<double, Inputs>::Zero();
   }
 
   /**
@@ -69,7 +69,7 @@ class LinearSystemSim {
    *
    * @return The current output of the plant.
    */
-  const Eigen::Matrix<double, Outputs, 1>& GetOutput() const { return m_y; }
+  const Eigen::Vector<double, Outputs>& GetOutput() const { return m_y; }
 
   /**
    * Returns an element of the current output of the plant.
@@ -84,9 +84,7 @@ class LinearSystemSim {
    *
    * @param u The system inputs.
    */
-  void SetInput(const Eigen::Matrix<double, Inputs, 1>& u) {
-    m_u = ClampInput(u);
-  }
+  void SetInput(const Eigen::Vector<double, Inputs>& u) { m_u = ClampInput(u); }
 
   /*
    * Sets the system inputs.
@@ -104,7 +102,7 @@ class LinearSystemSim {
    *
    * @param state The new state.
    */
-  void SetState(const Eigen::Matrix<double, States, 1>& state) { m_x = state; }
+  void SetState(const Eigen::Vector<double, States>& state) { m_x = state; }
 
   /**
    * Returns the current drawn by this simulated system. Override this method to
@@ -124,9 +122,9 @@ class LinearSystemSim {
    * @param u           The system inputs (usually voltage).
    * @param dt          The time difference between controller updates.
    */
-  virtual Eigen::Matrix<double, States, 1> UpdateX(
-      const Eigen::Matrix<double, States, 1>& currentXhat,
-      const Eigen::Matrix<double, Inputs, 1>& u, units::second_t dt) {
+  virtual Eigen::Vector<double, States> UpdateX(
+      const Eigen::Vector<double, States>& currentXhat,
+      const Eigen::Vector<double, Inputs>& u, units::second_t dt) {
     return m_plant.CalculateX(currentXhat, u, dt);
   }
 
@@ -137,17 +135,16 @@ class LinearSystemSim {
    * @param u          The input vector.
    * @return The normalized input.
    */
-  Eigen::Matrix<double, Inputs, 1> ClampInput(
-      Eigen::Matrix<double, Inputs, 1> u) {
+  Eigen::Vector<double, Inputs> ClampInput(Eigen::Vector<double, Inputs> u) {
     return frc::NormalizeInputVector<Inputs>(
         u, frc::RobotController::GetInputVoltage());
   }
 
   LinearSystem<States, Inputs, Outputs> m_plant;
 
-  Eigen::Matrix<double, States, 1> m_x;
-  Eigen::Matrix<double, Outputs, 1> m_y;
-  Eigen::Matrix<double, Inputs, 1> m_u;
+  Eigen::Vector<double, States> m_x;
+  Eigen::Vector<double, Outputs> m_y;
+  Eigen::Vector<double, Inputs> m_u;
   std::array<double, Outputs> m_measurementStdDevs;
 };
 }  // namespace frc::sim

wpilibc/src/main/native/include/frc/simulation/SingleJointedArmSim.h

@@ -142,9 +142,9 @@ class SingleJointedArmSim : public LinearSystemSim<2, 1, 1> {
    * @param u           The system inputs (voltage).
    * @param dt          The time difference between controller updates.
    */
-  Eigen::Matrix<double, 2, 1> UpdateX(
-      const Eigen::Matrix<double, 2, 1>& currentXhat,
-      const Eigen::Matrix<double, 1, 1>& u, units::second_t dt) override;
+  Eigen::Vector<double, 2> UpdateX(const Eigen::Vector<double, 2>& currentXhat,
+                                   const Eigen::Vector<double, 1>& u,
+                                   units::second_t dt) override;
 
  private:
   units::meter_t m_r;