KMAP & REDUCEK are the mapping list between non-reduced k and reducd k.
These files are generated by modified Elk code.
Format of KMAP:         
col   1: index of non reduced k points
col 2-4: lattice coordinates of k points 
col   5: corresponding indices of reduced k points

Format REDUCEDK.OUT:      
col   1: index of reduced k points
col 2-4: lattice coordinates of reduced k points