 README file for Benchmark B, a simple 3-D multigrid solver.

  The file  'mgrid.f'  demonstrates the simple 3-D multigrid
  solver of kernel B.  It requires no input file, and its output
  should be the contents of file  'mgrid.tiny.out'.  The size of the grid
  is  32 by 32 by 32,  large enough to demonstrate fairly good
  performance on a vector computer.

  To run the Class A case, on a  256 by 256 by 256  grid, edit 
  three parameter statements to replace  lm=5  with  lm=8,  and 
  compile on a machine with 60 MW (or 240 MB) of memory available.  
  Then the output should match that in file  'mgrid.A.out'.

  To run the Class B case, increase the number of iterations to 20.
  Then the output should match that in file  'mgrid.B.out'.

  Both sample output files are based on four multigrid iterations.
  
