z1: ZANGLES GROUP=1-5 SWITCH={RATIONAL D_0=2.0 R_0=0.5 D_MAX=5.0}
z2: ZXTORSIONS GROUP=1-5 SWITCH={RATIONAL D_0=2.0 R_0=0.5 D_MAX=5.0}
 
h: HISTOGRAM DATA=z1,z2 GRID_BIN=20,20 GRID_MIN=0,-pi GRID_MAX=pi,pi BANDWIDTH=0.2,0.2 
iv: INTEGRATE_GRID GRID=h 

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