AMBER Archive (2003)

Subject: Newton-Raphson minimization for large systems

From: Qing Zhang (qingzhang_nyu_at_yahoo.com)
Date: Wed May 14 2003 - 18:09:07 CDT


Dear Amber users:

I want to do Newton-Raphson minimization in Nmode for
a system with 4000 atoms, because CG minimization for
entropy calculation can not give a gradient less than
0.0001 for this large system. I thus gave a larger
"MAXMEMX" value in file src/nmode/sizes.h in AMBER 7
to make Newton-Raphson work for large systems. But it
didn't work because of the memory limit (from Fortran,
not from my server that has huge free memory). So I
compiled AMBER 7 again with -64 instead of default
-n32 option on SGI. The compilation passed, but when
minimization (in nmode) begins, it report a library
error:

"lib-4001 : UNRECOVERABLE library error

A READ operation tried to read past the end-of-file.

Encountered during a sequential unformatted READ from
unit 53
Fortran unit 53 is connected to a sequential
unformatted file:
  "tbp-tata_rec.crd.1"
IOT Trap"

Anyone has a clue on this? Thanks a lot.

Qing Zhang
New York University

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