a: GROUP ATOMS=1-102
b: GROUP ATOMS=103
c: GROUP ATOMS=104

w1: BRIDGE BRIDGING_ATOMS=a GROUPA=b GROUPB=c SWITCH={RATIONAL R_0=1.0}
w2: BRIDGE BRIDGING_ATOMS=a,a GROUPA=b GROUPB=c SWITCH={RATIONAL R_0=1.0}
w4: BRIDGE BRIDGING_ATOMS=a,a,a,a GROUPA=b GROUPB=c SWITCH={RATIONAL R_0=1.0}
w8: BRIDGE BRIDGING_ATOMS=a,a,a,a,a,a,a,a GROUPA=b GROUPB=c SWITCH={RATIONAL R_0=1.0}
w16: BRIDGE BRIDGING_ATOMS=a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a GROUPA=b GROUPB=c SWITCH={RATIONAL R_0=1.0}

x1: COMBINE ARG=w1 COEFFICIENTS=16 PERIODIC=NO
x2: COMBINE ARG=w2 COEFFICIENTS=8 PERIODIC=NO
x4: COMBINE ARG=w4 COEFFICIENTS=4 PERIODIC=NO
x8: COMBINE ARG=w8 COEFFICIENTS=2 PERIODIC=NO
x16: COMBINE ARG=w16 COEFFICIENTS=1 PERIODIC=NO

# all these numbers should be identical
PRINT ARG=x1,x2,x4,x8,x16 FILE=colvar FMT=%8.4f
