d1: DISTANCE ATOMS=1,10
d2: DISTANCE ATOMS=50,40
md: PBMETAD ARG=d1,d2 SIGMA=0.1,0.2 HEIGHT=1.0 PACE=10 TEMP=300 BIASFACTOR=5 FILE=HILLS.0,HILLS.1 GRID_WFILES=grid0,grid1 GRID_WSTRIDE=10 GRID_MIN=0,0 GRID_MAX=10,10
co: COMBINE ARG=md.bias COEFFICIENTS=-1 PERIODIC=NO
BIASVALUE ARG=co
