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PROGRAM CHILSQ

Least squares refinement from magnetic structure factor data
(paramagnetic version)

Description:

Main program for least squares refinement, of magnetic structure factor data from (possibly) mixed nuclear and magnetic reflections
Paramagnetic structure factors with anisotropic susceptibility

Input:

The crystal data file must contain all cards needed for magnetic and nuclear structure factor calculations vis:
S cards giving the symmetry.
A C card with the cell dimensions.
A cards defining the atoms, their positions and isotropic. temperature factors.
F cards giving the magnetic and non-magnetic scattering factors
Q cards defining the magnetic structure (Q STYP PARA)
optionally:
T cards giving anisotropic temperature factors

Additionally:
L cards indicating which parameters should be refined
Probably only REFI type 5 (flipping ratios) is useful (see the CCSL users' manual)

I cards which may have the words words NCYC, CYCL1, PRIN,
MCOR and CONV
NCYC the number of least squares cycles (default 3)
CYC1 the number to be assigned to the first cycle (default 1)
PRIN frequency at which output lists are printed
PRIN = 0 no printing
PRIN = 1 first cycle
PRIN = 2 last cycle
PRIN = 3 first and last cycles
PRIN = 4 every cycle

MCOR controls the correlations printed at the end of the job
(default +70)
MCOR = 0 whole correlation matrix printed
MCOR = -ve no printing
MCOR = +ve correlations above MCOR printed

CONV convergence criterion; LSQ cycling is terminated if the
maximum shift/esd < CONV (default 0.01)

The data file which should be a list of hkl and structure factors or flipping ratios in the format indicated by the L MODE and REFI cards .

Output:

The usual listing file reporting the data which have been read. This file also contains the output listings requested by the I PRIN card as well as the R-factors and chisqrd at the end of each least squares cycle.
A new crystal data file corresponding to the structure at the end of the least squares refinement.

Running the program:

On running the program the user is asked for the name of the crystal data file and the name of the file containing the structure factor data.
The value of \$\chi^2\$ at the end of each cycle is reported on the terminal.
Just before the last cycle the user is asked for a name for the new crystal data file.

Calls:

APSHSF CALCMG CENTRE DFLTCH ERRIN2 ERRMES LCHALC LFCALC LSETSF MATCOR MATINV MATSET MATSHF MATTOT MUCALC NOPFIL NWINSF PARRUN PARSSF PREFIN PRNCYC RELATE RFACS RREFSF SETFCM SETPOL STLSSF VARMAK VARSSF WGHTSF

Common blocks used:

/DEPMAT/ to use all members
/DGEOM/ to use UM
/FCAL/ to use FCMOD
/IOUNIT/ to use LPT ITO LUNI
/MCAL/ to use FMCMOD
/NEWOLD/ to use AMAXSH
/OBSCAL/ to use OBS GCALC YCALC DIFF NOBS WT
/POLDA/ to use POLND
/POSNS/ to use NATOM
/PRBLEM/ to use NFAM LF1SP
/REFINE/ to use NCYC NCYC1 LASTCY ICYC IPRNT MAG CONV
/SCLDAT/ to use ISCALE SCALE
/SCRACH/ to use MESSAG

*** CHILSQ updated C139 , DOCHI 1 and 2 to Library July 2005 ***

Classification:

General Least Squares Refinement . . . . . . . Main Program

LOGICAL FUNCTION DFLTCH(IFAM,IGEN,ISPC)

Calls:

DFLTCH

Called by:

CHILSQ DFLTCH

Common blocks used:

/MAGDAT/ to use MAGAT



SUBROUTINE LCHALC(H)

Calculates a magnetic structure factor and its derivatives.

Arguments:

On entry H is the 1x3 vector containing h,k,l

Prerequisite calls:

RECIP, SYMOP, SETANI, SETFOR and DOMAG must have been obeyed to set up the structure factor calculation. (They are all called by SETFCM)
The LSQ environment must have been set up by a suitable MAIN program (like
SFLSQ) which has called LSETUP and VARMAK.

Description:

On exit, in /MCAL/:
FMCMOD = modulus of FMC
FMCSQR = squared modulus of FMC
FMCDER is an array containing the derivatives of FMCMOD wrt the family
2 (structure) parameters, ALL MULTIPLIED BY FMCMOD.
(Note the difference from the specification of LFCALC's derivatives)

On exit, in /QCAL/:
Q is an array containing the magnetic interaction vectors for each domain
in general there will be NDOM*KCENT domains

On exit, in /QCALD/:
FQCDER is an array containing the derivatives of the Q's with respect to
all the family 2 parameters.

All the above will be zero if h,k,l is a magnetic absence

Notes:

Note the existence also of LFCALC (nuclear structure factors for LSQ)
FMCALC (magnetic structure factors)
FCALC (nuclear structure factors)

Calls:

ANITF C1MSCA CGMADD CGMSCA CGMZER CMRSCA FORMFA GMPRD GMSUB GMZER MAGABS ORTHO RCMPRD ROTSYM RSCALP SCALPR UNIVEC

Called by:

CHILSQ

Common blocks used:

/ANISO/ to use KATF IAPT
/BRAGG/ to use STHL SSQRD
/CONSTA/ to use TWOPI VALMUB
/MAGCHI/ to use all members
/MAGDAT/ to use NMAG JMAGAT NMFORM
/MCAL/ to use all members
/NSYM/ to use NOPC CENTRC
/PHASE/ to use JPHASE
/POSNS/ to use KX AMULT KTF SITE KSITE
/PRBLEM/ to use LVFST1 NVARF
/QCALD/ to use all members
/SYMDA/ to use TRANS

*** LCHALC new by PJB from LMCALC 20-Apr-2001 ***

Classification:

Magnetic Structure Factors . . . . . . . Crystallographic


Contents Manual

P. Jane Brown e-mail: brown@ill.fr
Institut Laue Langevin,
Grenoble, FRANCE