The error occurs again ( sorry that I haven’t update ipython notebook because it’s running) .
No error information at all  and I use top,
PR  NI    VIRT    RES    SHR S  %CPU %MEM     TIME+ COMMAND
20   0 17.009g 0.012t 124964 R  2000 19.0   8580:31 python
20   0 12.678g 9.038g 128752 S   0.0 14.4  76:30.30 python
it seems that the code is still running but cost 0 cpu. ( the machine has enough cpu and memory to run )
( The first line is the same code, but with different weight. The first runs well and the second seems strange).