Thanks a lot Ajay and Shyam sir for your valuable suggestions.
and solving Cahn-Hillard and Allen-Cahn equations for interface tracking.
I changed boundary conditions, re-examine declaration and initialization of scalar and vectors but everytime after exactly 1021000 steps i got same error (core dumped).
I am thinking (probably i am wrong), is there any limit in basilisk for number of steps ? or line num 245 in "events.h" (assert (n<INT_MAX); //check that dt is not too small), is this creating any problem. or anything else.
time step is 1e-5.
Your suggestions are valuable.
Thanks & regards