#!/bin/bash
# U scan: how the gap and the Fe local moment depend on U.
# For each U: rewrite the two U lines and the prefix (so runs don't collide),
# run pw.x, and pull three diagnostic lines out of the output:
#   - 'highest occupied, lowest unoccupied' appears only if a gap opened
#   - total magnetization should stay ~0 (AFM)
#   - absolute magnetization grows with U (stronger d localization)
for U in 0.001 2.0 4.0 4.6 6.0 8.0; do
  sed -e "s/^U Fe1-3d .*/U Fe1-3d $U/" -e "s/^U Fe2-3d .*/U Fe2-3d $U/" \
      -e "s/prefix      = 'FeO_U'/prefix      = 'FeO_U$U'/" feo_u.scf.in > tmp_U$U.in
  pw.x -in tmp_U$U.in > tmp_U$U.out
  GAP=$(grep 'highest occupied, lowest unoccupied' tmp_U$U.out | tail -1)
  MAG=$(grep 'total magnetization' tmp_U$U.out | tail -1)
  ABS=$(grep 'absolute magnetization' tmp_U$U.out | tail -1)
  echo "U=$U | $GAP | $MAG | $ABS"
done