Fix shake and dump errors

Dear all,

Could anybody explain what are the problems about using these commands?

fix 2 all shake 0.0001 20 0 b 2 a 2
dump 1 waterdump all atom 500 dump.waterinfo

where I got the following errors

ERROR: Could not find dump group ID (…/output.cpp:546)
ERROR: Unknown fix style (…/modify.cpp:762)

My input

***************** Initialization *********************

units real
dimension 3
boundary p p p
atom_style full
read_data atmdata.dat

group ox type 1
group hy type 2
group ca type 3
set group ox charge -0.8476
set group hy charge 0.4238
set group ca charge 0.0000

pair_style dpd/tstat 300.0 300.0 1.0 34387
comm_style brick
comm_modify vel yes
pair_style lj/cut/coul/long 10.0 10.0
pair_coeff 1 1 0.1553 3.169
pair_coeff 1 2 0.000000 0.000
pair_coeff 1 3 0.093627 3.190
velocity all create 300.0 34387 rot yes dist gaussian # for Oxygen
#velocity 2 create 300.0 34387 rot yes dist gaussian # for Hydrogen
kspace_style pppm 1.0e-6

*************** Setting ******************************

neighbor 2.0 bin
neigh_modify delay 0 every 10 check yes

thermo 100
thermo_style custom step elapsed dt time atoms lx ly lz xlo xhi ylo yhi zlo zhi
thermo_modify norm no flush yes

fix 2 all shake 0.0001 20 0 b 2 a 2
fix nvt all nvt temp 300.0 300.0 1.0
#fix_modify 1 temp myTemp press myPress

#dumps
dump 1 waterdump all atom 500 dump.waterinfo
write_data waterinfo.data
write_restart waterinfo.restart

timestep 0.2
run 100

Thanks in advance

Your dump command specifies the group “waterdump”
which doesn’t appear to be defined. If the
unknown fix error is for fix shake, you probably didn’t
build LAMMPS with that fix (from the RIGID package)
installed.

Steve