EPS  Spacing of floating point numbers.
    D = EPS(X), is the positive distance from ABS(X) to the next larger in
    magnitude floating point number of the same precision as X.
    X may be either double precision or single precision.
    For all X, EPS(X) = EPS(-X) = EPS(ABS(X)).

    EPS, with no arguments, is the distance from 1.0 to the next larger double
    precision number, that is EPS = 2^(-52).