Initialize the User-defined Aggregate in ECPG

Hi all,

I'm using the embedded SQL in C to create the User-Defined
Aggregate(UDA).
The command is :
CREATE AGGREGATE aggname( sfunc=kmeans,
stype=double precision[],
finalfunc=kmeansfinal,
INITCOND='{1,2,3}');

Since I need to do the aggregation in multiple rounds. I need to
initialize
the INITCOND using the execution result of last execution
（aggregation.）
Any one can tell me how can I initialize the INITCOND using host
variables
instead of hard code the INITCOND?

Thanks.

Jay