My colleague computed the Christoffel symbols to verify the calculations
given in Sean Carroll's book by using Maxima matrices. His session is
in the attachment.
I wanted to do the samr thing using the tensor package. It seemed it
would only take a few lines.
load("ctensor");
depends([alpha,beta], [t,r]);
ct_coordsys([-%e^^2*alpha,%e^^2*b,r^^2,r^^2*(sin(theta))^^2]);
cmetric();
lg:trigsimp(lg);
ug:trigsimp(ug);
christof();
I am told
(%i5) cmetric();
Division by 0#0: cmetric(dis=[])(ctensor.mac line 310) -- an error.
To debug this try debugmode(true);
(%i6) lg;
(%o6) matrix([0,0,0],[0,0,0],[0,0,0])
(%i7) ug;
(%o7) matrix([1,0,0],[0,1,0],[0,0,1])
So obviously I don't know what I am doing.
1. How should I do it?
2. How did he get that nice output of the WxMaxima session?
3. He said he got the Greek letters by simply puting in their names
without a preceding %. That didn't work for me? Is there a trick?
Thanks
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