b1: BOND_DIRECTIONS GROUP=1-5 SWITCH={RATIONAL D_0=2.0 R_0=0.5 D_MAX=5.0} 

h: HISTOGRAM VECTORS=b1 CONCENTRATION=10 GRID_BIN=100

iv: INTEGRATE_GRID GRID=h

b: RESTRAINT ARG=iv AT=0.75 KAPPA=10.0
PRINT ARG=iv,b.* FILE=colvar FMT=%8.4f
