OK  zero matrix                            lam=0+0j
OK  zero matrix 10                         lam=0+0j
OK  identity                               lam=1+0j
OK  diagonal                               lam=10+0j
OK  permutation (complex ring)             lam=-0.809+0.5878j
OK  2d rotation (complex pair)             lam=0.7648+0.6442j
OK  upper triangular of ones               lam=1+0j
OK  Jordan block (defective)               lam=2+0j
OK  symmetric                              lam=10.03+0j
OK  exactly singular integer               lam=5+0j
OK  swap                                   lam=1+0j
OK  1x1                                    lam=3+0j
OK  3000 scaled random matrices
