Data commit

Task/Polynomial-regression/Racket/polynomial-regression.rkt

@@ -0,0 +1,18 @@
+#lang racket
+(require math plot)
+
+(define xs '(0 1  2  3  4  5   6   7   8   9  10))
+(define ys '(1 6 17 34 57 86 121 162 209 262 321))
+
+(define (fit x y n)
+  (define Y (->col-matrix y))
+  (define V (vandermonde-matrix x (+ n 1)))
+  (define VT (matrix-transpose V))
+  (matrix->vector (matrix-solve (matrix* VT V) (matrix* VT Y))))
+
+(define ((poly v) x)
+  (for/sum ([c v] [i (in-naturals)])
+    (* c (expt x i))))
+
+(plot (list (points   (map vector xs ys))
+            (function (poly (fit xs ys 2)))))