Initial CommitHEADmain

1 files changed, 44 insertions, 0 deletions

diff --git a/main.rkt b/main.rkt
new file mode 100644
index 0000000..845bd18
--- /dev/null
+++ b/main.rkt
@@ -0,0 +1,44 @@
+#lang racket
+
+(require "modulo-arithmetic.rkt")
+
+;; 4a^3 + 27b^2 != 0
+(define a 2)
+(define b 3)
+
+(define (point-in-curve lst)
+  (define x (car lst))
+  (define y (cadr lst))
+  (= (* y y) (+ (* x x x) (* x a) b)))
+
+(define (add p q)
+  (cond ((not (point-in-curve p))
+         q)
+        ((not (point-in-curve q))
+         p)
+        (else
+         (define xp (first p))
+         (define xq (first q))
+         (define yp (second p))
+         (define yq (second q))
+         (let* ((m (if (equal? p q)
+                       (/ (+ (* 3 xp xp) a)
+                          (* 2 yp))
+                       (/ (- yp yq)
+                          (- xp xq))))
+                (xr (- (* m m) xp xq))
+                (yr (+ yp (* m (- xr xp)))))
+           (list xr (- yr))))))
+
+(define (mul n p)
+  (cond ((= n 0)
+         (list 0 0))
+        ((= n 1)
+         p)
+        (else
+         (add p (mul (sub1 n) p)))))
+
+(define curve-points (filter point-in-curve
+                             (cartesian-product (range cardinality)
+                                                (range cardinality))))
+