Tue Sep 07  2004  D tsukahara
	* derivative 0.1.2 made (not released yet)
	  * NumRu::Derivative
	    * fix ((<threepoint_O2nd_deriv>)) (=> NArrayMiss * NArray)
Tue Aug 17  2004  D tsukahara
	* derivative 0.1.1 make
          * GPhys::Derivative
  	    * Recast document in English
            * add 2nd order derivative method (given by T horinouti)
            * add test script end of derivative.rb
Sat Aug 14  2004  D tsukahara
	* derivative 0.1 make
	  * NumRu::Derivative
  	    * Recast document in English
	    * add test script end of derivative.rb
Fri Aug 13  2004  D tsukahara && T horinouti
	* derivative 0.0.4 make
	  * NumRu::Derivative
	    * add 2nd order derivative method (given by T horinouti)
Fri Aug 6  2004  D tsukahara
	* derivative 0.0.1 make (have not been released)
	    