Tensor[{l₁,l₂,l₃}]

creates a diffuison tensor with vectors {{0,0,1},{0,1,0},{1,0,0}} and eigenvalues {l1, l2, l3}.

Tensor[{l1,l2,l3},{e1,e2,e3}]

creates a diffuison tensor with vectors {e1, e2, e3} and eigenvalues {l1, l2, l3}.

Tensor[{l1,l2,l3},"Random"]

creates a diffuison tensor with random orthogonal eigenvectors {{e1e1, e2, e2} and eigenvalues {l1, l2, l3}.

Tensor[{l₁,l₂,l₃},"RandomZ"]

creates a diffuison tensor with random orthogonal eigenvectors {{1,0,0}, e2, e3} with random eigenvectors and eigenvalues {l1, l2, l3}.

Tensor[{l1,l2,l3},"OrtRandom"]

creates a diffuison tensor with random orthogonal eigenvectors {{1,0,0},{0,1,0},{0,0,1}} and eigenvalues {l1, l2, l3l3}}.

Tensor[]

is based on DOI: 10.1002/nbm.2959.