June 2018 Update

Task/Safe-addition/D/safe-addition.d

@@ -0,0 +1,16 @@
+import std.traits;
+auto safeAdd(T)(T a, T b)
+if (isFloatingPoint!T) {
+    import std.math;     // nexDown, nextUp
+    import std.typecons; // tuple
+    return tuple!("d", "u")(nextDown(a+b), nextUp(a+b));
+}
+
+import std.stdio;
+void main() {
+    auto a = 1.2;
+    auto b = 0.03;
+
+    auto r = safeAdd(a, b);
+    writefln("(%s + %s) is in the range %0.16f .. %0.16f", a, b, r.d, r.u);
+}

Task/Safe-addition/Java/safe-addition.java

@@ -0,0 +1,20 @@
+public class SafeAddition {
+    private static double stepDown(double d) {
+        return Math.nextAfter(d, Double.NEGATIVE_INFINITY);
+    }
+
+    private static double stepUp(double d) {
+        return Math.nextUp(d);
+    }
+
+    private static double[] safeAdd(double a, double b) {
+        return new double[]{stepDown(a + b), stepUp(a + b)};
+    }
+
+    public static void main(String[] args) {
+        double a = 1.2;
+        double b = 0.03;
+        double[] result = safeAdd(a, b);
+        System.out.printf("(%.2f + %.2f) is in the range %.16f..%.16f", a, b, result[0], result[1]);
+    }
+}

Task/Safe-addition/Julia/safe-addition.julia

@@ -0,0 +1,19 @@
+julia> using IntervalArithmetic
+
+julia> n = 2.0
+2.0
+
+julia> @interval 2n/3 + 1
+[2.33333, 2.33334]
+
+julia> showall(ans)
+Interval(2.333333333333333, 2.3333333333333335)
+
+julia> a = @interval(0.1, 0.3)
+[0.0999999, 0.300001]
+
+julia> b = @interval(0.3, 0.6)
+[0.299999, 0.600001]
+
+julia> a + b
+[0.399999, 0.900001]

Task/Safe-addition/Scala/safe-addition.scala

@@ -0,0 +1,13 @@
+object SafeAddition extends App {
+  val (a, b) = (1.2, 0.03)
+  val result = safeAdd(a, b)
+
+  private def safeAdd(a: Double, b: Double) = Seq(stepDown(a + b), stepUp(a + b))
+
+  private def stepDown(d: Double) = Math.nextAfter(d, Double.NegativeInfinity)
+
+  private def stepUp(d: Double) = Math.nextUp(d)
+
+  println(f"($a%.2f + $b%.2f) is in the range ${result.head}%.16f .. ${result.last}%.16f")
+
+}