joker.math/hypot

candid82 · Feb 5, 2018 · 207838a · 207838a
1 parent 42bf89d
commit 207838a
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Showing 3 changed files with 31 additions and 0 deletions.
diff --git a/std/math.joke b/std/math.joke
@@ -14,3 +14,9 @@
   {:added "1.0"
   :go "cos(x)"}
   [^Number x])
+
+(defn ^Double hypot
+  "Returns Sqrt(p*p + q*q), taking care to avoid unnecessary overflow and underflow."
+  {:added "1.0"
+  :go "hypot(p, q)"}
+  [^Number p, ^Number q])
diff --git a/std/math/a_math.go b/std/math/a_math.go
@@ -24,6 +24,22 @@ var cos_ Proc = func(args []Object) Object {
   return NIL
 }
 
+var hypot_ Proc = func(args []Object) Object {
+  c := len(args)
+  switch  {
+  case c == 2:
+
+    p := ExtractNumber(args, 0)
+    q := ExtractNumber(args, 1)
+    res := hypot(p, q)
+    return MakeDouble(res)
+
+  default:
+    PanicArity(c)
+  }
+  return NIL
+}
+
 var sin_ Proc = func(args []Object) Object {
   c := len(args)
   switch  {
@@ -49,6 +65,11 @@ mathNamespace.InternVar("cos", cos_,
     NewListFrom(NewVectorFrom(MakeSymbol("x"))),
     `Returns the cosine of the radian argument x.`, "1.0"))
 
+mathNamespace.InternVar("hypot", hypot_,
+  MakeMeta(
+    NewListFrom(NewVectorFrom(MakeSymbol("p"), MakeSymbol("q"))),
+    `Returns Sqrt(p*p + q*q), taking care to avoid unnecessary overflow and underflow.`, "1.0"))
+
 mathNamespace.InternVar("sin", sin_,
   MakeMeta(
     NewListFrom(NewVectorFrom(MakeSymbol("x"))),

diff --git a/std/math/math_native.go b/std/math/math_native.go
@@ -10,3 +10,7 @@ func sin(x Number) float64 {
 func cos(x Number) float64 {
 	return math.Cos(x.Double().D)
 }
+
+func hypot(p Number, q Number) float64 {
+	return math.Hypot(p.Double().D, q.Double().D)
+}