problem by deleting atoms (related: liggghtscommands, atom shrink)

hello everyone,

I am using CFDE to simulate the combustion process of particles. I wish the particlesl shrink after heating to 350 degrees and disappear after the radius is less than 0.003. I used two ways to solve the problem, but both got ERRORS.

1.way

I write the following code in in.liggghts_run:
------------------------------------------------------------------------------------------------------------------------
variable shrinkevery equal 100
variable Temptrigger equal 350
variable rate equal 0.99
variable tresh atom f_Temp>${Temptrigger}
variable tresh atom f_Temp>350
compute rad all property/atom radius
variable dshrunk atom 2.*c_rad*(v_tresh*${rate}+(1.-v_tresh))
variable dshrunk atom 2.*c_rad*(v_tresh*0.99+(1.-v_tresh))
fix grow all adapt ${shrinkevery} atom diameter v_dshrunk
fix grow all adapt 100 atom diameter v_dshrunk

variable radiussmall atom c_rad<0.003
group Asche variable radiussmall
----------------------------------------------------------------------------------------------------------------------------
and the codeline: delete_atoms group Asche in ../CFD/Constant/liggghtsCommands
----------------------------------------------------------------------------------------------------------------------------
executeProps1
{
command
(
delete_atoms
blanks
group
blanks
Asche
);
runFirst off;
runLast off;
runEveryCouplingStep on;
}
------------------------------------------------------------------------------------------------------------------------------

In the simulation Error shows: ERROR: Compute used in variable between runs is not current. Use the update_on_run_end option for computes to avoid this. (../variable.cpp:1094) so the c_rad will not be updated during the simulation.
I added the update_on_run_end yes after compute rad all property/atom radius. The Error shows ERROR: Invalid keyword in compute property/atom command. It seems that update_on_run_end yes not suitable for this codeline.

2.Way

I write 3 codeline in ../CFD/constant/liggghtsCommand
variable radiussmall atom c_rad<0.003
group Asche variable radiussmall
delete_atoms group Asche

--------------------------------------------------------------------------------------------------------------------------------

FoamFile
{
version 2.0;
format ascii;

root "";
case "";
instance "";
local "";

class dictionary;
object liggghtsCommands;
}

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

liggghtsCommandModels
(
runLiggghts
execute
);

executeProps1
{
command
(
variable
radiussmall
atom
noBlanks
c_rad
<
number
);
scalars
(
0.003
);

runFirst off;
runLast off;
runEveryCouplingStep on;
}

executeProps2
{
command
(
group
Asche
variable
radiussmall
);
runFirst off;
runLast off;
runEveryCouplingStep on;
}

executeProps3
{
command
(
delete_atoms
blanks
group
blanks
Asche
);
runFirst off;
runLast off;
runEveryCouplingStep on;
}
-----------------------------------------------------------------------------------------------

but just the first codeline will be readed in the simulation:
-----------------------------------------------------------------------------------------------
Total # of neighbors = 500
Ave neighs/atom = 2.5
Neighbor list builds = 0
Dangerous builds = 0
Executing command: 'variable radiussmall atom c_rad<0.003000'
variable radiussmall atom c_rad<0.003000
LIGGGHTS finished
-----------------------------------------------------------------------------------------------------------

my question:
which way is the correct way to delete the atoms?
if the first way is correct: how to update the c_rad?
if the second way is correct: how to run the three executeProps on by one?

I am grateful for your help！

kind regards

Jiang