src/math/matrices.lisp

   1
   2 (in-package :lineal.math)
   3
   4 (defun mtrix-transpose (mtrix)
   5   (apply #'mapcar #'list mtrix))
   6
   7 (defun mtrix-addn (&rest matrs)
   8   (apply #'mapcar #'tuple-addn matrs))
   9
  10 (defun mtrix-subtrn (&rest matrs)
  11   (apply #'mapcar #'tuple-subtrn matrs))
  12
  13 (defun scalar-mtrix-multn (k a)
  14   "Multiply a scalar /k/ and matrix /a/."
  15   (mapcar
  16     (lambda (arow)
  17       (scalar-tuple-multn k arow))
  18     a))
  19
  20 (defun mtrix-mult2n (a b)
  21   "Multiply 2 matrices."
  22   (mapcar
  23     (lambda (arow)
  24       (apply #'tuple-addn
  25              (mapcar #'scalar-tuple-multn
  26                      arow b)))
  27     a))
  28
  29 (defun mtrix-multn (&rest mats)
  30   "Standard matrix multiplication."
  31   (do ((a (car mats) (mtrix-mult2n a (car tomult)))
  32        (tomult (cdr mats) (cdr tomult)))
  33     ((endp tomult) a)))
  34
  35 (defun mtrix-coltuple-multn (a u)
  36   (declare (inline dot-prod))
  37   "Multiply matrix /a/ and column vector /u/."
  38   (loop :for row :in a
  39         :collect (dot-prod row u)))
  40
  41