AMBER Archive (2008)

Subject: AMBER: Comment: constant pH, non-integer charge -> weird error

From: Markus Kaukonen (
Date: Sun Sep 14 2008 - 02:51:58 CDT

Dear All,
This is just a comment.

I made a mistake in my preparation of prep files for Amber10 which
resulted a total charge of -4.53 (this was incorrect) in prmtop file.
I then proceeded running sander with constant pH and got a strange error:

>At line 1320 of file _mdread.f (Unit 18 "cpin1")
>Traceback: not available, compile with -ftrace=frame or -ftrace=full
>Fortran runtime error: In line 1 of namelist cnstph:
>Bad name

When I later corrected the total charge ( it was now -4) the constant
pH is running fine.

So if you encounter this strange error check the total charge of your system...

Terveisin Markus

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