Program "killed" in the Virtual Machine [Windows 8.1]

[Keccogrin]

Hello,
I am using VMware Workstation 12 Player (with host = Windows 8.1, Intel(R) Core(TM) i7-3632QM CPU @ 2.20GHz, 64-bit o.s., RAM = 8 GB) (and guest = Ubuntu 14.04-LTS).
When I try to run a (particularly big) program written in Fortran (which would require 13-14 hours as I estimated), at the very beginning (when some matrices are built) the message "Killed" appears, and the program stops.
What is the problem here?
I think it should not be a problem of memory size because I have 23.5 GB used and 22.5 GB free.
Maybe is it the small RAM?
I've also tried to set the memory of the Virtual Machine to the "maximum recommended memory = 6320 MB (Memory swapping may occur beyond this size.)", but nothing.


Thank you in advance,
Bye,


Francesco