Wednesday, October 17, 2012

GRtensor commands

I would try to collect some useful resources for GRtensor package of Maple.
I contains a host of commands which are very useful but the documentation is scarce.

A good page to learn the applicability of the commands through example is

All GRtensor outputs needs o be simplified one way or another and GRtensor provides specialized routines to accomplish just that. The gralter command does the job instead of the Maple command simplify.

And everyone needs to know the keyboard shortcuts of any program they are using. It makes life efficient.

For example, I was unable to enter the Greek symbols for a long time till I found that it is very easy to do so in Maple. Just type the Greek word in English and press escape key. A menu pops up displaying all names that can be entered which begins with the letters entered. Most of the time it is the first entry. So I just start typing lamb ESC and press enter to get the λ symbol.


To calc. with a general form and then substitute the functional form use subs command.

So if I have to calc. the G_ab of a complicated metric which is of the f(r) metric form then I would instead calc. using the f(r) metric and then substitute the functional form of the f(r) .

But this works only for individual components of a tensor which are extracted by the grcomponent command. To apply the substitution on an entire tensor w have to use the grmap command.


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