Hi, I'm very new at this. I'm trying to look at components of a stress-energy tensor (I got the correct results on a trial case), and getting some weird output involving column vectors, inverse matrices, and tetrad unit vector things, and I was hoping somebody could tell me what my problem is and maybe how I could fix it.
Needs["xAct`xTensor`"]
Needs["xAct`xCoba`"]
Needs["xAct`xTras`"]
DefManifold[M4, 4, {a, b, c, d, e, f, g, h}];
DefChart[cb, M4, {0, 1, 2, 3}, {uu[], v[], y[], z[]},
ChartColor -> Blue]
cb /: CIndexForm[0, cb] := "u";
cb /: CIndexForm[1, cb] := "v";
cb /: CIndexForm[2, cb] := "y";
cb /: CIndexForm[3, cb] := "z";
DefConstantSymbol[G];
DefConstantSymbol[c1];
DefConstantSymbol[c2];
DefConstantSymbol[c3];
DefConstantSymbol[c4];
DefScalarFunction[aa];
DefScalarFunction[U];
DefScalarFunction[V];
u = CTensor[{1/Sqrt[2], 1/Sqrt[2], 0, 0}, {cb}];
g = CTensor[{{0, -1, 0, 0}, {-1, 0, 0, 0}, {0, 0,
Exp[V[uu[]] - U[uu[]]], 0}, {0, 0, 0,
Exp[-(U[uu[]] + V[uu[]])]}}, {-cb, -cb}];
SetCMetric[g, cb, SignatureOfMetric -> {3, 1, 0}];
CD = CovDOfMetric[g];
MetricCompute[g, cb, All];
Then I entered the tensor function like T[a_,b_]:=<stuff from another notebook where I used variation to get the equations of motion>
then I get the 00-component of the tensor in a nice simplified form, but other components I get nastiness like you see in the attached pictures. What can I do? Thanks.