1valid symmetric matrix (A=A+A^T where A=sparse(magic(4))) |sym4 2 3 1 1 1 3isa 4 4 10 0 4(26I3) (40I2) (26I3) 5 1 5 8 10 11 6 1 2 3 4 2 3 4 3 4 4 7 32 7 12 17 22 17 22 12 27 2 8