add an "InvalidInput" enum, used by the SuperLU interface
add an "InvalidInput" enum, used by the SuperLU interface

rotorliu/eigen,madlib/eigen_backup,mjbshaw/Eigen,mjbshaw/Eigen,madlib/eigen_backup,mjbshaw/Eigen,rotorliu/eigen,mjbshaw/Eigen,rotorliu/eigen,rotorliu/eigen,madlib/eigen_backup,madlib/eigen_backup