Data commit

Task/Miller-Rabin-primality-test/EchoLisp/miller-rabin-primality-test.l

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+(lib 'bigint)
+
+;; output : #t if n probably prime
+(define (miller-rabin n (k 7) (composite #f)(x))
+(define d (1- n))
+(define s 0)
+(define a 0)
+(while (even? d)
+	(set! s (1+ s))
+	(set! d (quotient d 2)))
+
+(for [(i k)]
+	(set! a (+ 2 (random (- n 3))))
+	(set! x (powmod a d n))
+	#:continue (or (= x 1) (= x (1- n)))
+	(set! composite
+	(for [(r (in-range 1 s))]
+		(set! x (powmod x 2 n))
+		#:break (= x 1) => #t
+		#:break (= x (1- n)) =>  #f
+		#t
+		))
+	 #:break composite => #f )
+ (not composite))
+
+;; output
+(miller-rabin #101)
+    → #t
+(miller-rabin #111)
+    → #f
+(define big-prime (random-prime 1e+100))
+3461396142610375479080862553800503306376298093021233334170610435506057862777898396429
+6627816219192601527
+(miller-rabin big-prime)
+    → #t
+(miller-rabin (1+ (factorial 100)))
+    → #f
+(prime? (1+ (factorial 100))) ;; native
+    → #f