procedure mainvali ( infilename,outfilename : in string );
-- DESCRIPTION :
-- This is the routine for validating the solutions of a polynomial system,
-- as called by the central dispatcher.
-- The arguments are the names of the input and output file respectively.
-- FUNCTIONALITY :
-- There are three types of functionality offered:
-- 1. Weeding out the solution sets:
-- check residuals to separate solutions from path failures;
-- compute local condition numbers, which solution are regular/singular;
-- see whether solutions are clustered, eventually multiple solutions;
-- compute generators of the solution set in case of symmetry.
-- 2. Computation of winding numbers:
-- this requires a homotopy with solution paths at t < 1.
-- 3. Validation of polyhedral end game:
-- computation of frequency table of the path directions;
-- this requires an output file of poco where the path directions
-- have been computed.