Fix is_symmetric
Fix is_symmetric

agisga/nmatrix,wlevine/nmatrix,janusnic/nmatrix,johnmarinelli/nmatrix,wlevine/nmatrix,agisga/nmatrix,janusnic/nmatrix,wlevine/nmatrix,johnmarinelli/nmatrix,janusnic/nmatrix,wlevine/nmatrix,agisga/nmatrix,johnmarinelli/nmatrix,johnmarinelli/nmatrix,janusnic/nmatrix,agisga/nmatrix