September Morn Update

Task/Nth-root/Scala/nth-root-1.scala

@@ -0,0 +1,9 @@
+def nroot(n: Int, a: Double): Double = {
+  @tailrec
+  def rec(x0: Double) : Double = {
+    val x1 = ((n - 1) * x0 + a/math.pow(x0, n-1))/n
+    if (x0 <= x1) x0 else rec(x1)
+  }
+
+  rec(a)
+}

Task/Nth-root/Scala/nth-root-2.scala

@@ -0,0 +1,2 @@
+def fallPrefix(itr: Iterator[Double]): Iterator[Double] = itr.sliding(2).dropWhile(p => p(0) > p(1)).map(_.head)
+def nrootLazy(n: Int)(a: Double): Double = fallPrefix(Iterator.iterate(a){r => (((n - 1)*r) + (a/math.pow(r, n - 1)))/n}).next

Task/Nth-root/Scala/nth-root.scala

@@ -1,16 +0,0 @@
-object NthRoot {
-
-  def main(args: Array[String]) {
-    println(nthroot(3, 32))
-  }
-
-  def nthroot1(n: Int, a: Double): Double = {
-    def loop(x0: Double) : Double = {
-      val x1 = (1.0d/n * ((n - 1) * x0 + a/math.pow(x0, n-1)))
-      if (x0 <= x1) x0
-      else loop(x1)
-    }
-
-    return loop(a/2)
-  }
-}