I want to impose gravity in certain part of a cell using fix gravity command.
In order to accomplish this task, i must use dynamic group to update atoms in the group.But it seems that the fix gravity command conflict with dynamic group command.
COMMANDS i used
"#define the Gravity region
variable zlow equal (v_zmin+v_zmax)*0.25
variable zhi equal (v_zmin+v_zmax)*0.75
region gbox_reg block INF INF INF INF 0.0 50.0 #v_zlow v_zhi
group gbox dynamic all region gbox_reg
#fix g1 gbox gravity v_gm vector 0 0 -1
fix g1 gbox gravity 1.0 vector 0 0 -1"
"ERROR: Fix g1 does not allow use of dynamic group (../modify.cpp:226)"
What shall i do to overcome this problem?