  In this and subsequent papers, one dimensional system of Dirac fermions with
a random-varying mass is studied by the transfer-matrix methods which we
developed recently. We investigate the effects of nonlocal correlation of the
spatial-varying Dirac mass on the delocalization transition. Especially we
numerically calculate both the "typical" and "mean" localization lengths as a
function of energy and the correlation length of the random mass. To this end
we introduce an imaginary vector potential as suggested by Hatano and Nelson
and solve the eigenvalue problem. Numerical calculations are in good agreement
with the results of the analytical calculations. We obtain the relation between
the localization length of states and the correlation length of the random
mass. In subsequent paper, we shall study Dirac fermions with a random mass of
long-ranged correlations.
