anchor.diff:                                               :input-constraints (vector i j)
                                                :output-rank 0)))))
   
  +(defun zeros (m &optional (n m))
  +  (assert (plusp m))
  +  (assert (plusp n))
  +  (reshape 0 (make-shape (range 1 m) (range 1 n))))
  +
  +(declaim (inline δ))
  +(defun δ (i j)
  +  (declare (type integer i j))
  +  (if (= i j) 1 0))
  +
  +(defun eye (m &optional (n m))
  +  (assert (plusp m))
  +  (assert (plusp n))
  +  (let ((shape (make-shape (range 1 m) (range 1 n))))
  +    (αδ (indices shape 0) (indices shape 1))))
  +
   (defun transpose (x)
     (reshape
      (coerce-to-matrix x)
  
positive.code:         (values (coerce-to-scalar max)
                  (coerce-to-scalar index))))))
  
  (defun matmul (a b)
    (β #'+
       (α #'*
          (reshape (coerce-to-matrix a) (τ (m n) (n m 1)))
          (reshape (coerce-to-matrix b) (τ (n k) (n 1 k))))))
  
negative.code: 
  (defun amax (x)
    (flet ((amax-fn (lmax lind rmax rind)
             (if (>= (abs lmax) (abs rmax))
                 (values lmax lind)
                 (values rmax rind))))
      (let ((vector (coerce-to-matrix x)))
  