   }
   
   func magnitude() -> Float {
-    return sqrt(magnitudeSquared())
+    return sqrtf(magnitudeSquared())
   }
   
   func norm() -> Vec4f {

  // Construct a rotation matrix
  static func rotate(v: Vec3f, angle: Float) -> Mat4f {
    let r = angle.toRadians()
    let c = cos(r)
    let s = sin(r)
    let (x, y, z) = (v.x, v.y, v.z)
    let (x2, y2, z2) = (x*x, y*x, z*z)
    return Mat4f(

// Math module for core vector and matrix operations.
#if os(Linux)
  import Glibc
#else
  import Darwin
#endif

extension Float {

