Fix compilation issue in mat = permutation (regression introduced in 0e78c04fea69)
Fix compilation issue in mat = permutation (regression introduced in 0e78c04fea69)

ritsu1228/eigen,pasuka/eigen,ritsu1228/eigen,ritsu1228/eigen,pasuka/eigen,ritsu1228/eigen,pasuka/eigen,ritsu1228/eigen,pasuka/eigen,pasuka/eigen