k points along high symmetry lines
 40              ! number of points per line
line mode
fractional
  0    0    0    G
  0.5  0    0    X

  0.5  0    0    X
  0.5  0.5  0    S

  0.5  0.5  0    S
  0    0.5  0    Y

  0    0.5  0    Y
  0    0    0    G

  0    0    0    G
  0    0    0.5  Z
