Not exactly plotting, but at least data visualisation ...
I have a matrix which looks as follows, generated here in Mathematica from a 4x4 identity matrix and a tensor product of Pauli matrices:
H := 5.907 IdentityMatrix[4] + .2183 KroneckerProduct[
PauliMatrix[3], IdentityMatrix[2]] -
6.125 KroneckerProduct[IdentityMatrix[2], PauliMatrix[3]] -
2.143 (KroneckerProduct[PauliMatrix[1], PauliMatrix[1]] +
KroneckerProduct[PauliMatrix[2], PauliMatrix[2]]);
H // MatrixForm
what I'd like to do is highlight the block diagonal bits - i.e. elements (1,1), (4,4) and the 2x2 block in the middle. From some searching of the internet (particularly this useful page) and the Mathematica documentation, I see that the Background attribute can be applied to a Grid view of the matrix:
bg = {None,
None, {{1, 1} -> LightGreen, {4, 4} ->
LightGreen, {{2, 3}, {2, 3}} -> LightGreen}};
Grid[H, Background -> bg]
which has indeed highlighted the elements that I wanted it to, but at the expense of no longer using the brackets of MatrixForm. I you ask for this to be printed in MatrixForm, the background colouring disappears. As far as I have been able to work out, the Background attribute cannot be combined with MatrixForm. Oh well, the blocking is still as I wanted.
The syntax for Background is given in the hyperlink above.
