For a long time I was used to using Matlab as a mathematical tool.  After several years  I switched to the Mathematica to deal with the symbolic computings. While my doctoral supervisor and my firend use Maple to calculate the metric and the equations. Today I learn of this powerful tool and get aware of the advantages of Maple compare to Mathematica. And I realized that Maple is very cool, I mean really really cool ! And also might be very handy.

I will learn to use this tool, and hope it is really comfortable.