Function: math-matrix-inv-raw

math-matrix-inv-raw is an autoloaded and byte-compiled function defined in calc-mtx.el.gz.

Signature

(math-matrix-inv-raw M)

Source Code

;; Defined in /usr/src/emacs/lisp/calc/calc-mtx.el.gz
;;; Matrix inverse and determinant.
(defun math-matrix-inv-raw (m)
  (let ((n (1- (length m))))
    (if (<= n 3)
	(let ((det (math-det-raw m)))
	  (and (not (math-zerop det))
	       (math-div
		(cond ((= n 1) 1)
		      ((= n 2)
		       (list 'vec
			     (list 'vec
				   (nth 2 (nth 2 m))
				   (math-neg (nth 2 (nth 1 m))))
			     (list 'vec
				   (math-neg (nth 1 (nth 2 m)))
				   (nth 1 (nth 1 m)))))
		      ((= n 3)
		       (list 'vec
			     (list 'vec
				   (math-sub (math-mul (nth 3 (nth 3 m))
						       (nth 2 (nth 2 m)))
					     (math-mul (nth 3 (nth 2 m))
						       (nth 2 (nth 3 m))))
				   (math-sub (math-mul (nth 3 (nth 1 m))
						       (nth 2 (nth 3 m)))
					     (math-mul (nth 3 (nth 3 m))
						       (nth 2 (nth 1 m))))
				   (math-sub (math-mul (nth 3 (nth 2 m))
						       (nth 2 (nth 1 m)))
					     (math-mul (nth 3 (nth 1 m))
						       (nth 2 (nth 2 m)))))
			     (list 'vec
				   (math-sub (math-mul (nth 3 (nth 2 m))
						       (nth 1 (nth 3 m)))
					     (math-mul (nth 3 (nth 3 m))
						       (nth 1 (nth 2 m))))
				   (math-sub (math-mul (nth 3 (nth 3 m))
						       (nth 1 (nth 1 m)))
					     (math-mul (nth 3 (nth 1 m))
						       (nth 1 (nth 3 m))))
				   (math-sub (math-mul (nth 3 (nth 1 m))
						       (nth 1 (nth 2 m)))
					     (math-mul (nth 3 (nth 2 m))
						       (nth 1 (nth 1 m)))))
			     (list 'vec
				   (math-sub (math-mul (nth 2 (nth 3 m))
						       (nth 1 (nth 2 m)))
					     (math-mul (nth 2 (nth 2 m))
						       (nth 1 (nth 3 m))))
				   (math-sub (math-mul (nth 2 (nth 1 m))
						       (nth 1 (nth 3 m)))
					     (math-mul (nth 2 (nth 3 m))
						       (nth 1 (nth 1 m))))
				   (math-sub (math-mul (nth 2 (nth 2 m))
						       (nth 1 (nth 1 m)))
					     (math-mul (nth 2 (nth 1 m))
						       (nth 1 (nth 2 m))))))))
		det)))
      (let ((lud (math-matrix-lud m)))
	(and lud
	     (math-lud-solve lud (calcFunc-idn 1 n)))))))