error CS0019: Operator `&' cannot be applied to operands of type `float' and `float'

Hi this code that´s ok but I want to set "running" when the player press left shift... In this original code of tutorial in their functions are walk and jump but miss run. I don´t know how to make this...

    [System.Serializable]
     public class MoveSettings{
         public float runVel = 30;
         public float forwardVel = 12;
         public float rotateVel = 100;
         public float jumpVel = 25;
         public float distToGrounded = 0.1f;
         public LayerMask ground;
     }
 
     [System.Serializable]
     public class PhysSettings{
         public float downAccel = 0.75f;
     }
 
     [System.Serializable]
     public class InputSettings{
         public float inputDelay = 0.1f;
         public string JUMP_AXIS = "Jump";
         public string TURN_AXIS     = "Horizontal";
         public string FORWARD_AXIS = "Vertical";
         public string RUN_AXIS = "Speed";
     }
 
     public MoveSettings moveSetting = new MoveSettings ();
     public PhysSettings physSetting = new PhysSettings ();
     public InputSettings inputSetting = new InputSettings ();
 
     Vector3 movement;                   // The vector to store the direction of the player's movement.
     Animator anim;                      // Reference to the animator component.
     Rigidbody rBody;          // Reference to the player's rigidbody.
 
 
     Vector3 velocity = Vector3.zero;
     Quaternion targetRotation;
     float jumpInput, turnInput, forwardInput, runInput;
 
 
     public bool alive = true;
 
     void onTriggerEnter(Collider other){
         if (other.gameObject.name == "eyes") {
             other.transform.parent.GetComponent<GuardaRealMovement6> ().checkSight();
         }
     }
 
     public Quaternion TargetRotation {
         get{ return targetRotation; }
     }
 
     bool Grounded(){
         return Physics.Raycast (transform.position, Vector3.down, moveSetting.distToGrounded, moveSetting.ground);
     }
 
     void Awake ()
     {
         
         anim = GetComponent <Animator> ();
     
     }
     void Start(){
         targetRotation = transform.rotation;
         if (GetComponent<Rigidbody> ())
             rBody = GetComponent<Rigidbody> ();
         else
             Debug.LogError ("The character needs a rigidbody.");
         
         forwardInput = turnInput = jumpInput = runInput = 0;
 
     }
 
     void GetInput(){
         forwardInput = Input.GetAxis (inputSetting.FORWARD_AXIS);
         jumpInput = Input.GetAxisRaw (inputSetting.JUMP_AXIS);
         turnInput = Input.GetAxis (inputSetting.TURN_AXIS);
         runInput = Input.GetAxisRaw (inputSetting.RUN_AXIS);
     }
     void Update(){
         GetInput ();
         Turn ();
 
     }
 
     void FixedUpdate ()
     {
         
         // Animate the player.
     
 
         Animating (forwardInput);
         RunFast ();
         Run ();
         Jump ();
         rBody.velocity = transform.TransformDirection (velocity);
 
     }
     void Animating (float forwardInput)
     {
         // Create a boolean that is true if either of the input axes is non-zero.
         bool walking = forwardInput != 0f;
 
         // Tell the animator whether or not the player is walking.
         anim.SetBool ("IsWalking", walking);
     }
 
     void Run (){
         if(Mathf.Abs(forwardInput)>inputSetting.inputDelay){
             //move
             //rBody.velocity = transform.forward*forwardInput*moveSetting.forwardVel;
             velocity.z = moveSetting.forwardVel*forwardInput;
         }
         else{
             //zero.velocity
             //rBody.velocity=Vector3.zero;
             velocity.z = 0;}
         }
     void RunFast (){
         if(Mathf.Abs(forwardInput & runInput)>inputSetting.inputDelay){
             //move
             //rBody.velocity = transform.forward*forwardInput*moveSetting.forwardVel;
             velocity.z = moveSetting.runVel*forwardInput;
         }
         else{
             //zero.velocity
             //rBody.velocity=Vector3.zero;
             velocity.z = 0;}
     }
 
 
     void Turn ()
     {
         if (Mathf.Abs (turnInput) > inputSetting.inputDelay) {
 
             targetRotation *= Quaternion.AngleAxis (moveSetting.rotateVel * turnInput * Time.deltaTime, Vector3.up);
         }
         transform.rotation = targetRotation;
     }
     void Jump(){
         if(jumpInput>0 && Grounded()){
             //jump
             velocity.y=moveSetting.jumpVel;
         }
         else if(jumpInput == 0 && Grounded()){
             //zero out our velocity
             velocity.y=0;
         }
         else{
             //decrease velocity.y
             velocity.y -=physSetting.downAccel;
         }
 
     }