The isotropic constant $L_K$ is an affine-invariant measure of the spread of
a convex body $K$. For a $d$-dimensional convex body $K$, $L_K$ can be defined
by $L_K^{2d} = \det(A(K))/(\mathrm{vol}(K))^2$, where $A(K)$ is the covariance
matrix of the uniform distribution on $K$. It is an