Re: [AMBER] Convergence issue in rism1d

From: tluchko <tluchko.protonmail.com>
Date: Mon, 14 Mar 2022 17:50:01 +0000

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------- Original Message -------

On Friday, March 11th, 2022 at 4:56 AM, David A Case <david.case.rutgers.edu> wrote:

> On Fri, Mar 11, 2022, angad sharma wrote:
>
> > I am trying to to rism1d with the following inputs:
> >
> > &SPECIES
> >
> > DENSITY=0.1d0,
> >
> > MODEL="$AMBERHOME/dat/rism1d/model/MG2.mdl"
>
> > But it is not converging and giving error like this:
> >
> > ERROR> RXRISM: reached steps limit Maxstep=10000
>
> I'll let Tyler make specific suggestions, but will make this comment:
>
> 100 mM Mg (or any divalent ion) is a very high concentration for RISM to
>
> handle. Would a smaller value (say 10 mM) satisfy your needs?
>

You can try solving for a lower concentration of ions first and then use the restart file as a starting point for a higher concentration of ions. Even then, 100 mM Mg may not converge.

Using restart file with different parameters is one of the strategies described in section 7.3.1 of the Amber 21 manual (page 118).

Tyler

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Received on Mon Mar 14 2022 - 11:00:02 PDT
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