This block defines an explicit set of k-points and their weights for a periodic-system calculation. The first column is the weight of each k-point and the following are the components of the k-point vector. You only need to specify the components for the periodic directions. Note that the k-points should be given in Cartesian coordinates (not in reduced coordinates), in the units of inverse length. The weights will be renormalized so they sum to 1 (and must be rational numbers).
For example, if you want to include only the Gamma point, you can use:
1.0 | 0 | 0 | 0
electrons/kpoints.F90 : 811
if (parse_block(namespace, 'KPoints', blk) /= 0) then