derivative.rb in gphys-1.4.3

- old
+ new

@@ -15,9 +15,11 @@
 * ((<module NumRu::Derivative>))
   * ((<threepoint_O2nd_deriv>))
     * First derivative (2nd Order difference use three point.)
   * ((<cderiv>))
     * First derivative (center difference use two point.)
+  * ((<deriv2d>))
+    * 2nd derivative
   * ((<b_expand_linear_ext>))
     * return array extended boundaries with linear extention.
   * ((<cdiff>))
     * return difference. (center difference)
 