Matrix multiplication: Difference between revisions

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@@ Line 2,083: / Line 2,083: @@
 =={{header|Emacs Lisp}}==
 <syntaxhighlight lang="lisp">
+(defvar M1 '((2 1 4)
+             (0 1 1)))
+(defvar M2 '(( 6  3 -1  0)
-(let ()
+             ( 1  1  0  4)
-  (defun matrices-multiply (m1 m2)
-    (let (fn-row-mult)
+             (-2  5  0  2)))
-      (setq fn-row-mult
-	    (lambda (row col-idx)
-	      (let ((col (cl-loop for m2-row in m2
-				  collect (nth col-idx m2-row))))
-		(apply '+ (cl-loop for v1 in row for v2 in col
-				   collect (* v1 v2))) ) ) )
-      (cl-loop for m1-row in m1 collect
-	       (seq-map-indexed (lambda (v col-idx)
-				  (funcall fn-row-mult m1-row col-idx) )
-				(nth 0 m2) ) ) ) )
-  (let ((m1 '((2 1 4)
+(seq-map (lambda (a1)
+           (seq-map (lambda (a2) (apply #'+ (seq-mapn #'* a1 a2)))
-	      (0 1 1)))
+                    (apply #'seq-mapn #'list M2)))
-	(m2 '((6 3 -1 0)
-	      (1 1 0 4)
+         M1)
-	      (-2 5 0 2)))
-	result-matrix)
-    (switch-to-buffer-other-window "**matrix-result**")
-    (erase-buffer)
-    (setq result-matrix (matrices-multiply m1 m2))
-    (cl-loop for line in result-matrix do
-	     (insert (format "%s\n"
-			     (apply 'concat
-				    (seq-map (lambda (item) (format "%5s " item)) line) ) ) ) ) )
-  )
 </syntaxhighlight>
 {{out}}
 <pre>
-27    -2    12
+((5 27 -2 12) (-1 6 0 6))
-   -1     6     0     6
 </pre>