diff --git a/regtest/basic/rt11/plumed.dat b/regtest/basic/rt11/plumed.dat
index c8ea0710b64da7d079d1db0a47e54e1b49a2774e..51b2acf421ea521d99683df7fb37073307fcb5c4 100644
--- a/regtest/basic/rt11/plumed.dat
+++ b/regtest/basic/rt11/plumed.dat
@@ -1,14 +1,14 @@
 d1: DISTANCE ATOMS=1,10
 vol: VOLUME 
 
-METAD ARG=d1,vol SIGMA=0.1,0.2 HEIGHT=1.0 PACE=10 LABEL=md TEMP=300 GRID_MIN=0.0,120.0 GRID_MAX=2.0,130.0 BIASFACTOR=10 GRID_BIN=100,100 FMT=%14.6f
-METAD ARG=d1,vol SIGMA=0.1,0.2 HEIGHT=1.0 PACE=10 LABEL=md1 TEMP=300 GRID_MIN=0.0,120.0 GRID_MAX=2.0,130.0 BIASFACTOR=10 GRID_BIN=50,300 GRID_SPACING=0.02,0.1 FMT=%14.6f FILE=h1
-METAD ARG=d1,vol SIGMA=0.1,0.2 HEIGHT=1.0 PACE=10 LABEL=md2 TEMP=300 GRID_MIN=0.0,120.0 GRID_MAX=2.0,130.0 BIASFACTOR=10 GRID_SPACING=0.02,0.1 FMT=%14.6f FILE=h2
-METAD ARG=d1,vol SIGMA=0.1,0.2 HEIGHT=1.0 PACE=10 LABEL=md3 TEMP=300 GRID_MIN=0.0,120.0 GRID_MAX=2.0,130.0 BIASFACTOR=10 FMT=%14.6f FILE=h3
+METAD ARG=d1,vol SIGMA=0.1,0.2 HEIGHT=1.0 PACE=10 LABEL=md TEMP=300 GRID_MIN=0.0,120.0 GRID_MAX=2.0,130.0 BIASFACTOR=10 GRID_BIN=100,100 FMT=%14.6f GRID_SPARSE
+METAD ARG=d1,vol SIGMA=0.1,0.2 HEIGHT=1.0 PACE=10 LABEL=md1 TEMP=300 GRID_MIN=0.0,120.0 GRID_MAX=2.0,130.0 BIASFACTOR=10 GRID_BIN=50,300 GRID_SPACING=0.02,0.1 FMT=%14.6f FILE=h1 GRID_SPARSE
+METAD ARG=d1,vol SIGMA=0.1,0.2 HEIGHT=1.0 PACE=10 LABEL=md2 TEMP=300 GRID_MIN=0.0,120.0 GRID_MAX=2.0,130.0 BIASFACTOR=10 GRID_SPACING=0.02,0.1 FMT=%14.6f FILE=h2 GRID_SPARSE
+METAD ARG=d1,vol SIGMA=0.1,0.2 HEIGHT=1.0 PACE=10 LABEL=md3 TEMP=300 GRID_MIN=0.0,120.0 GRID_MAX=2.0,130.0 BIASFACTOR=10 FMT=%14.6f FILE=h3 GRID_SPARSE
 
 # this is doubling the force
 # (to test TAU)
-METAD ARG=d1,vol SIGMA=0.1,0.2 TAU=1.122452 PACE=10 TEMP=300 GRID_MIN=0.0,120.0 GRID_MAX=2.0,130.0 BIASFACTOR=10 GRID_BIN=100,100 FMT=%14.6f FILE=HILLSX
+METAD ARG=d1,vol SIGMA=0.1,0.2 TAU=1.122452 PACE=10 TEMP=300 GRID_MIN=0.0,120.0 GRID_MAX=2.0,130.0 BIASFACTOR=10 GRID_BIN=100,100 FMT=%14.6f FILE=HILLSX GRID_SPARSE
 
 PRINT ...
   STRIDE=1