CHARMM c35b1 mscale.doc



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                     Multi Scale Command: MSCALE

         The multiscale command causes CHARMM to run several
independent but connected calculations using subsystems. The
calculations can use either CHARMM or other programs with a consistent
interface.

                 by Milan Hodoscek and Bernard Brooks


* Menu:

* Syntax::              Syntax of the mscale specification
* Examples::            Examples to run the MSCAle command
* Notes::               Notes abot the MSCAle command



File: Mscale -=- Node: Syntax
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[SYNTAX MSCAle]

Main script commands:

MSCAle [ NSUBsystems integer ]

SUBSystem keyname [ PROGram filename ]  [ CRYStal ]  [ATOM]  -
                      [ NPROC integer ] [ FNPR integer ] atom-selection -
                   [ COEFf   real ]  [ LAMBda ]  [ MLAMbda ] -
                     [ INPUt filename ] [ OUTPut filename ]

SYSDisplay

END

Subsystem commands:

SERVer [ NCALls integer ] [ ATOM ] [ CRYStal ]

Meaning of individual keywords:

SUBSystem        - Create a new subsystem
NSUBS     	 - the number of SUBSystems to be setup
keyname          - Always read but currently not used for further usage in the
                    code. Must follow immediately the SUBSystem keyword.
                    This is the name of the subsystem.
COEFf real       - coefficient with which to scale the energy/forces
                    of this subsystem
LAMBda           - Also scale by PERT's lambda value
MLAMbda          - Also scale by PERT's 1-lambda value
ATOM             - Flag to decide on communication of atom data:
                    number of atoms in this subsystem and their atomic
                    numbers in floating point format
NPROC            - How many processes this subsystem will use. eg
                    semipempirical methods 1, since they are not
                    parallel, but ab initio and some MM methods can use
                    parallel here.
FNPRoc           - Forward this number to the program which is run
                    through the interface in CALL SYSTEM(). Only works
                    with ATOM flag!

The folowing 3 keywords must be specified. There are no defaults for them!

PROGram          - the filename of the program to execute for this subsystem

INPUt            - the filename of the script to run on the subsystem

OUTPut           - the filename of the output from the program

CRYStal          - communicate also crystal data and the virial. Must
                   be specified also on the server command

SYSDisplay       - Display the info about the whole setup

END              - Must be specified to end the MSCAle block.

SERVer           - Put CHARMM in server mode.

NCALLs integer   - Number of energy calls in server mode before going
                    to next CHARMM command in the server script.
                    If the number is not specified, the command will
                    run until the client terminates.




File: Mscale -=- Node: Examples
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EXAMPLE 1: Typical input for substraction method (ONIOM):

Main script:

READ/GENERATE PSF
READ PARAM
READ COOR

MSCAle NSUBs 2

SUBSystem high coef 1.0 program "charmm" input "sub1.inp" -
          output "sub1.out"  sele resid 4 end

SUBSystem low coef -1.0 program "charmm" input "sub2.inp" -
          output "sub2.out"  sele resid 4 end

END

DYNA ....


Subsystem 1 (sub1.inp)

READ/GENERATE PSF for one residue
READ PARAM (one kind of parameters)
READ COOR
NBONDS
SERVER

Subsystem 2 (sub2.inp)

READ/GENERATE PSF for one residue
READ PARAM (different kind of parameters than in one)
READ COOR
NBONDS
SERVER




File: Mscale -=- Node: Notes
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Miscellaneous Notes:

I.

To dynamically start new processes in parallel MPI-2 standard is used,
namely MPI_COMM_SPAWN routine. It is availalble in OpenMPI library
(currently in use) and MPICH-2. MPICH-2 has some problems with
standard I/O so it is not recommended for use as of June 2007.


II.

Matrices for coefficients in substraction methods:

L=low level theory, H=high level theory
B=big system, S=small system

     B    S
L    1   -1

H    0    1

If you have 3 levels:L, M, H, and 3 reagions B, M, S: B > M > S!

     B    M    S
L    1   -1    0

M    0    1   -1

H    0    0    1

III.

How to do the additive methods ?



File: Mscale -=- Node: Interfaces
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MSCAle Interfaces contributed by: H. Lee Woodcock (hlwood-at-nih-dot-gov),
Joseph D. Larkin (jlarkin-at-bloomu-dot-edu), and Milan Hodoscek
(milan-at-cmm-dot-ki-dot-si).

Currently four (4) external QM programs are interfaced to CHARMM via the
MSCAle command. These programs are in addition to the currently supported
QM packages that are interfaced with CHARMM (GAMESS, GAMESS-UK, Q-Chem,
SCC-DFTB, ect.).

1. NWChem         (http://www.emsl.pnl.gov/docs/nwchem/nwchem.html)
2. MOLPRO         (http://www.molpro.net/)
3. PSI 3          (http://www.psicode.org/) License:(GPL)
4. GAUSSIAN 03    (http://www.gaussian.com/)

Support for additional QM packages is underway and will be added in the 
future. To request support for a particular package please contact 
H. Lee Woodcock, Joseph D. Larkin, or Milan Hodoscek.

Below are examples of how to run the various QM packages via MSCAle. All 
packages require a control file that dictates the options to be passed 
to the individual package. 

-----------------------------------------------------------------------------

1. NWChem: Here is an example of control file that is needed for a NWChem 
calculation... 

title "for interface"

basis "ao basis"
 * library "6-31g*"
end

geometry  noautosym

end

task dft gradient

task shell "/bin/rm -f sys1.b sys1.b^-1 sys1.c sys1.db"
task shell "/bin/rm -f sys1.gridpts.0 sys1.grinfo.0"
task shell "/bin/rm -f sys1.movecs sys1.p sys1.zmat"

-----------------------------------------------------------------------------

2. MOLPRO: Here is an example of control file that is needed for a MOLPRO 
calculation...

***Title
memory,1,m

SET,CHARGE=0
BASIS=sto-3g

thresh,energy=1.d-10
hf
optg,maxit=0,coord=cart,startcmd=hf

-----------------------------------------------------------------------------

This file will perform a single SCF analytic gradient calculation. If a method 
that does not support analytic gradients (i.e. CCSD(T)) is desired the "optg" 
line must be changed to read like the following line:

optg,numerical,maxit=0,coord=cart,displace=cart,startcmd=hf

The correct geometry section will be written with the correct keywords immediately 
following the line containing the "memory" specification.

-----------------------------------------------------------------------------

3. PSI 3: Here is an example of control file that is needed for a PSI 3 
calculation...

psi: (
  label = "Title"
  no_reorient=true
  subgroup=c1
  jobtype = sp
  wfn = scf
  reference = rhf
  dertype = first
  basis = "STO-3G"
  geometry = (
 )
)

In this case the "no_reorient" keyword must be used to keep all forces in the 
correct reference frame. The current molecular geometry will be placed automatically 
in the "geometry" section.

-----------------------------------------------------------------------------

4. Gaussian 03: Here is an example of control file that is needed for a G03 
calculation...

%mem=100MB
%NProcShared=2
%NProcLinda=4
#HF/sto-3g FORCE NOSYMM

***user specified title

0 1
-----------------------------------------------------------------------------

Here it should be noted the last line in the control file should be the spin 
and multiplicity specifications. i.e. there should be no blank line at the 
end of this control file as there is in a typical gaussian input file as the 
current geometry will be appended and the final blank line inserted afterwards.