;******************************************************************
;Program:  MatInv.lsp
;Name:     Tihomir Bojanic, dipl.ing.geodezije
;Country:  Serbia
;Sity:     Novi Sad
;Adress:   Sterijina 15/15
;Mail:     tikab@nadlanu.com
;Language: Serbian
;Date:     27.07.2007.
;******************************************************************
(defun MATINV(QQ / i j k n R H)
   ;inverzija matrice QQ  (SHARP)
   (setq n (fix (sqrt (length QQ))) i 0)
   (while (< i n)
      (setq i (1+ i) QQ (setmat QQ i i (+ (getmat QQ i i) 1.0)))
   )
   (setq k 0)
   (while (< k n)
      (setq k (1+ k) R (- (getmat QQ k k) 1) j 0)
      (while (< j n)
         (setq j (1+ j) QQ (setmat QQ k j (/ (getmat QQ k j) R)))
      )
      (setq i 0)
      (while (< i n)
         (setq i (1+ i) H (getmat QQ i k) j 0)
         (if (/= i k)(progn
            (while (< j n)
               (setq j (1+ j) QQ (setmat QQ i j (- (getmat QQ i j) (* H (getmat QQ k j)))))
            )
         ))
      )
   )
   (setq i 0)
   (while (< i n)
      (setq i (1+ i) QQ (setmat QQ i i (- (getmat QQ i i) 1.0)))
   )
   QQ
)
;********************************************************************
;Funkcija za matricni racun u programskom jeziku AutoLISP
;********************************************************************
(defun IJ(i j / )
   ;formiranje asocijativnog clana matrice
   (atof (strcat (itoa i) "." (itoa j)))
)
;********************************************************************
(defun DIMAT(m n / i j AA)
   ;dimenzionisanje matrice AA(m,n)
   (setq i 0 AA '())
   (while (< i m)
      (setq j 0 i (1+ i))
      (while (< j n)
         (setq j (1+ j) AA (cons (list (IJ i j) 0.0) AA))
      )
   )
   (reverse AA)
)
;********************************************************************
(defun GETMAT(AA i j / )
   ;daje AA(i,j) matrice
   (cadr (assoc (IJ i j) AA))
)
;********************************************************************
(defun SETMAT(AA i j BB / k)
   ;prima vrednost AA(i,j) matrice
   (setq k (IJ i j) AA (subst (list k BB) (assoc k AA) AA))
)
;********************************************************************
(princ)