  The truncation and approximation errors for the set of numerical solutions
computed by methods based on the algorithms of different structure are
calculated and analyzed for the case of the two-dimensional steady inviscid
compressible flow. The truncation errors are calculated using a special
postprocessor, while the approximation errors are obtained by the comparison of
the numerical solution and the analytic one. The extent of the independence of
errors for the numerical solutions may be estimated via the Pearson correlation
coefficient that may be geometrically expressed by the angle between errors.
Due to this reason, the angles between the approximation errors are computed
and related with the corresponding angles between the truncation errors. The
angles between the approximation errors are found to be far from zero that
enables a posteriori estimation of the error norm. The analysis of the
distances between these solutions provides another approach to the estimation
of the error. The comparison of the error norms, obtained by these two
procedures, is provided that demonstrates the acceptable values of their
effectivity indices. The results of the approximation error norm estimation for
the supersonic flows, containing shock waves, are presented. The measure
concentration phenomenon and the algorithmic randomness give some insights into
these results.
