Hi Vasantha,

This is a generic segfault error and it's impossible to know what's wrong without more details on your system. A few ideas: use cpptraj's "check" action to see if you have some bad contacts in your structure. Do this on the input but also save your coordinates at the minimization step just before the segfault and check that. Use ntpr=1 when running your minimization and monitor the output energies/gradients to see if anything looks bad. 

Also, posting your question to the Amber mailing list will likely give you a quicker helpful response.

Pawel

A segmentation violation, or segfault, indicates an attempted illegal memory access or write, and the operating system helpfully kills the program (rather than bringing down the entire machine!).  If this doesn't make sense to you, then the take-home message is that "something went wrong, but we don't know what".

Segfaults are almost always a bug in the code.  The bug is also frequently not catching bad input and quitting before the segfault happens.  If you haven't already, I suggest asking this question in the Amber mailing list; you will probably need to provide the prmtop, inpcrd, and input file for people to reproduce the errors you're seeing.

Hi Pawel and Jason

Thank you so much for your suggestions...

As you mentioned I will also post  my question in the Amber mailing list. In the mean time I will also test cpptraj's "check"..

thank you

Vasantha