Conver ASCII format covariance matrix to back binary form

GROMACS version: 2018
GROMACS modification: No
Hello, is there any straightforward way how to convert covariance matrix in ASCII format to binary form available for gmx to process it and diagonalize it? I am aware I could diagonalize it externally but I would like to have eigenvalues and eigenvectors as trr file so I could process it further by gmx utilities.