anchor.diff:  * sign - provides the sign of a value (1 if positive, -1 if negative, 0 if 0).
   * log - provides the link:http://en.wikipedia.org/wiki/Natural_logarithm[natural logarithm] of a value.
   * sqrt - provides the link:http://en.wikipedia.org/wiki/Square_root[square root] of a value.
  -* invSqrt - provides the inverse link:http://en.wikipedia.org/wiki/Square_root[square root] of a value (1 / sqrt(value).
  +* invSqrt - provides the inverse square root of a value (1 / sqrt(value).
   
   
   ==== Linear Algebra
  
positive.code: 
  === Rotation Matrix
  
  Commonly you might find yourself with a <<jme3/matrix#,Matrix>> defining a rotation. In fact, it's very common to contain a rotation in a <<jme3/matrix#,Matrix>> create a Quaternion, rotate the Quaternion, and then get the <<jme3/matrix#,Matrix>> back. Quaternion contains a `fromRotationMatrix` method that will create the appropriate Quaternion based on the give <<jme3/matrix#,Matrix>>. The `toRotationMatrix` will populate a given <<jme3/matrix#,Matrix>>.
  
  
  ==== Example - Rotate a Spatial Using a Rotation Matrix
  
negative.code: * counterClockwise - given three points (defining a triangle), the winding is determined. 1 if counter-clockwise, -1 if clockwise and 0 if the points define a line.
  * pointInsideTriangle - calculates if a point is inside a triangle.
  * sphericalToCartesian - converts a point from link:https://en.wikipedia.org/wiki/Spherical_coordinate_system[spherical coordinates] to link:https://en.wikipedia.org/wiki/Cartesian[cartesian coordinates].
  * cartesianToSpherical - converts a point from cartesian coordinates to link:https://en.wikipedia.org/wiki/Spherical_coordinate_system[spherical coordinates].
  
  
  ==== Misc.
  