Least squares refinement from measured structure factors
Description:
-
Main program for least squares refinement of structure factors.
Extinction corrections can be included and the extinction parameters refined.
Geometric slack constraints can be included (see chaper 5 of the CCSL users
manual and the documentation of program BONDS)
Input:
-
The crystal data file must contain all cards needed for 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 scattering factors
optionally:
-
T cards
giving anisotropic temperature factors
Additionally:
-
L cards
indicating which parameters should be refined
- (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 tyhe 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 the measured structure
factors as implied by the
L MODE card
.
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.
Notes:
-
The EXTERNAL parameters DFLTSF,DUMMY,PARRUN,LFCALC,VARSSF,DUMPAR
are the names of routines called to set parameters and carry out
calculations which may be different in different types of LSQ. For further
Information see chapter 5 of the CCSL manual.
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.
After the last cycle user is asked for a name for the new crystal data file.
Calls:
- APSHSF
CALCSF
CENTRE
DFLTSF
ERRIN2
ERRMES
GEOMCO
GEOMIN
GEOMLS
LDUMMY
LFCALC
LSETSF
MATCOR
MATINV
MATSET
MATSHF
MATTOT
MESS
NOPFIL
NWINSF
PARRUN
PARSSF
PREFIN
PRNCYC
RELATE
RFACS
RREFSF
SETFC
STLSSF
VARMAK
VARSSF
WGHTSF
Common blocks used:
-
- /DEPMAT/ to use all members
- /EXTN/ to use IEXTYP
- /FCAL/ to use FC FCMOD
- /IOUNIT/ to use LPT ITO LUNI
- /NEWOLD/ to use AMAXSH
- /NSYM/ to use CENTRC
- /OBSCAL/ to use OBS GCALC DIFF NOBS WT
- /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
- /SLAKDA/ to use NSLAK
- /SLKGEO/ to use SLONLY
*** SFLSQ updated by PJB to use DOTHER 3rd-Apr-2001 ***
Classification:
General Least Squares Refinement . . . . . . . Main Program
P. Jane Brown
e-mail: brown@ill.fr
Institut Laue Langevin,
Grenoble, FRANCE