I understand that but I dont think virual memeory management would affect the use of memory, this is what operation system and c library should gurantee. If malloc return sucess I should be able to use it freely. In fact I have run my program on my laptop with a smaller memory size and it works fine. So that is why I suspect setonix doesn't give enough resource. And I know some other students have similar issue about that. Anyway, I'll have a test again but I don't expect that works since I have tested many times. Probably the only solution is not to create the original matrix but I am not sure if it fits the project guidline.