C ==========================================================================
C   
C    
C                   ---  SFCHECK ---
C                                             /Vers 5.3.4 10.06.99/
C
C  A program for assessing the agreement between the atomic model and
C  X-ray data. 
C
C  The program requires one or two input files, with the coordinates of the 
C  model (in PDB or CIF or BLANC format) and structure factors (in CIF or PDB 
C  or BLANC format), and runs completely automatically.
C  Non-crystallographic symmetry information is extracted from the 
C  coordinates file and is used when nesessary to restore the content
C  of the asymmetric part of the unit cell.
C
C  I. Output information produced by SFCHECK:
C
C   1.Crystal: 
C       cell parameters and space group
C
C   2.Model: 
C       number of atoms
C       number of water molecules
C       solvent content  
C       <B> for model
C       Matthews coefficient and corresponding solvent %
C       reported resolution 
C       reported R-factor
C
C   3.Refinement:
C       refinement program
C       resolution range for refinement
C       reported sigma cut-off for refinement
C       reported R-factor
C       reported Rfree
C
C   4.Structure factors:
C       number of reflections
C       number of reflections with I > sigma
C       number of reflections with I > 3sigma
C       resolution range
C       completeness
C       R-standard (sum(sigma)/sum(F))
C       Wilson plot (amplitudes vs. resolution)
C       overall B-factor by Patterson origin peak and by Wilson plot
C       optical resolution 
C       expected minimal error in coordinates
C       Anisotropic distribution of Structure Factors -ratio of Eigen values 
C
C   5.Model vs. structure factors:
C       R-factor
C       Correlation coefficient
C       R-factor for reported resolution range and sigma cut-off
C       Rfree    
C       Luzzati plot (R-factor vs. resolution)
C       coordinate error from Luzzati plot
C       expected maximal error in coordinates
C       DPI
C       Patterson scaleing   - scale , Badd
C       Anisothermal scaling - betas: b11,b22,b33,b12,b13,b23
C       Solvent correction - Ks,Bs
C
C   Optical resolution
C
C     Optical resolution is defined as an expected minimum distance
C     between two resolved peaks in the electron density map. It is
C     computed as (del_patt*2)/sqrt(2), where del_patt is the width of
C     the Patterson origin peak.
C     The "expected optical resolution for complete data set" is  
C     calculated as above but using all reflections, with values for
C     missing reflection being the average value in the corresponding
C     resolution shell.
C     Plot of Optical resolution for an atom with B=0 demonstrates
C     behavior of the part of Optical resolution corresponded on the 
C     series termination.
C 
C   Patterson scaling
C
C     Scaling in SFCHECK is based on the Patterson origin peak which is
C     approximated as a gaussian. Compared to the conventional scaling 
C     by the Wilson plot, this method is particularly advantageous when
C     only low resolution data are available.
C     The program gives overall B-factors estimated by both methods.
C
C   Low resolution cut-off
C
C     Disordered solvent contributes to diffraction at low resolution.
C     However, removing of low resolution data from calculations results
C     in a series termination effect which is noticeable in the electron
C     density at the surface of the molecule. To reduce the influence of
C     low resolution terms, SFCHECK applies the "soft" low resolution 
C     cut-off to structure factors according to the formula:
C
C         Fnew = Fold (1-exp(-Boff*s^2)) , where Boff = 4dmax^2
C 
C     Program uses Boff = 256
C
C   Scaling
C     
C     Program scales Fobs and Fcalc by the Patterson origin peak using all
C     data applying Boff.
C     First, computes Boveralls for observed and calculed amplitudes.
C     Second, makes the width of the calculated peak equal to the 
C     observed, i.e. computes an additional termal factor Badd:
C       
C           Badd = Boverall_obs - Boverall_calc
C 
C     Third, computes the scale factor for Fcalc:
C
C                                 sum(Fobs^2*(1-exp(-Boff*s^2)))
C           scale = sqrt ( --------------------------------------------- )
C                          sum(Fcalc^2*exp(-Badd*s^2)*(1-exp(-Boff*s^2)))
C
C     Finally we have:
C
C           Fcalc_scaled = Fcalc * scale * exp(-Badd*s^2)   
C
C     The program computes R-factor and Correlation coefficient for all
C     data applying the soft low resolution cut-off as described above. 
C     The program also computes R-factor and Correlation coefficient for
C     the reported resolution range and reported sigma cut-off without
C     applying Boff. If the Fobs file contains reflections marked with
C     the Rfree flag, the program computes Rfree.
C 
C   Completeness 
C
C     Missing data are restored by using the average values of 
C     intensities for the corresponding resolution shell.
C     The program produces a plot of completeness vs. resolution and
C     a plot of the average radial completeness in polar coordinates
C     theta and phi.
C
C   Expected minimal error  
C
C     The minimal coordinate error is estimated using experimental 
C     sigmas(F). The standard deviation of atomic coordinates is 
C     
C        sig_min(r) = sqrt(3)*sigma(slope)/curvature
C
C             where  sigma(slope) is a slope of electron density in the 
C                                 x direction ( along A).             
C                    curvature is an average curvature of the electron 
C                                 density in the atomic peak center.
C        
C     and computed as:
C 
C      sigma(slope) = (2pi*sqrt(sum(h^2*(sigF)^2)))/(VOL*A)')
C
C                    VOL - volume of cell
C                    A   - cell parameter
C                    h   - Miller index        
C                    summation over all reflections
C
C                   ( Cruickshank,D.W.J. (1949) Acta.Cryst 2, 65.) 
C
C      curvature  = (2pi^2*sum(h^2*F))/(VOL*A^2)')
C        
C                   ( Murshudov et al., (1997) Acta.Cryst D532, 240.) 
C 
C     If there is no experimental sigma for observaed data, the program
C     uses  sigma = Fobs * 0.04 for all reflections.
C           
C   Expected maximal error  
C
C     Expected maximal error in coordinates is estimated  by the difference
C     between !Fobs! and !Fcalc!:
C
C      sig_max(r) = sqrt(3)*sigma(slope)/curvature
C
C      sigma(slope) = (2pi*sqrt(sum(h^2*(Fobs-Fcalc)^2)))/(VOL*A)')
C
C      curvature  = (2pi^2*sum(h^2*F))/(VOL*A^2)')
C 
C     For missing reflections the program uses the average value of 
C     sigma(Fobs) for the corresponding resolution shell instead 
C     of (Fobs-Fcalc).
C
C   DPI - diffraction-data precision indicator
C     
C     The Cruickshank's method of estimation of coordinate error.
C                  ( the Refinement of Macromolecular structure Proceeding
C                    of CCP4 Study weekend. pp11-22 1996)
C                
C       sig(x) = sqr(Natoms/(Nobs-4Natoms)) C^-1/3 dmin Rfact
C
C               where  C     - fractional completeness.
C                      Rfact - convential crystallographic R-factor
C                      Nobs  - number of reflections 
C                      Dmin  - maximal resolution
C       
C      If Rfree flags are specified, the program uses the Murshudov's approach 
C      to calculate DPI: 
C                  (Newsletter on protein crystallography., Daresbury
C                   Laboratory, (1997) 33, pp 25-30.)
C
C       sig(x) = sqr(Natoms/Nobs) C^-1/3 dmin Rfree
C   
C   Luzzati plot (R-factor vs. resolution)
C
C      Program computes the average radial error <delta(r)> in coordinates 
C      by Luzzati plot.
C                         <delta(r)> = 1.6 sig(x)
C
C   Solvent content  
C
C      Solvent content is the fraction of the unit cell volume not occupied
C      by the model. The model consists of ALL atoms present in the coordinate 
C      file.
C
C
C   Residual factor Rmerge 
C
C                           sum_i (sum_j |Ij - <I>|)
C               Rmerge(I) = --------------------------
C                                sum_i (sum_j (<I>))
C
C               Ij  = the intensity of the jth observation of reflection i
C               <I> = the mean of the intensities of all observations of
C                      reflection i
C
C               sum_i is taken over all reflections
C               sum_j is taken over all observations of each reflection
C
C
C II. Local error estimation
C
C   Local error estimation (plotted for each residue, for the backbone
C   and for the side chain):
C      1. Amplitude of displacement of atoms from electron density
C      2. Density correlation coefficient
C      3. Density index 
C      4. B-factor
C      5. Index of connectivity
C
C   Displacement
C
C     Displacement of atoms from electron density is estimated from the
C     difference (Fobs - Fcal) map. The displacement vector is the ratio of
C     the gradient of difference density to the curvature. The amplitude of
C     the displacement vector is an indicator of the positional error.
C
C   Correlation coefficient
C
C     The density correlation coefficient is calculated for each residue
C     from atomic densities of (2Fobs-Fcalc) map - "Robs" and the model
C     map (Fcalc) - "Rcalc" :
C
C     D_corr =  <Robs><Rcalc>/sqrt(<Robs**2><Rcalc**2>)
C
C         where <Robs> is the mean of "obsereved" densities of atoms of residue
C               (backbone or side chain).
C 
C               <Rcalc> is the mean of "calculateded" densities of atoms of 
C               residue.
C
C         Value of density for some atom from map R(x) is:
C
C                  sum_i ( R(xi) * Ratom(xi - xa) )
C         Dens =  ---------------------------------- 
C                      sum_i ( Ratom(xi - xa) ) 
C
C           where  Ratom(x) is atomic electron density for x-th point of grid.
C                  xa - vector of the centre of atom.
C                  xi - vector of the i-th point of grid.
C                  Sum is taken over all grid points which have distance
C                  from the centre of atom less than Radius_limit.
C                  For all atoms Radius_limit = 2.5 A.
C
C   Index of density and index of connectivity
C
C     The index of connectivity is the product of the (2Fobs-Fcal) electron 
C     density values for the backbone atoms N, CA and C, i.e. the geometric
C     mean value for these atoms. Low values of this index indicate breaks 
C     in the backbone electron density which may be due to flexibility of 
C     the chain or incorrect tracing.  The index of density is a similar 
C     indicator which is calculated for all atoms of a given residue.
C
C
C III. Omit procedure
C
C     An omit map is a way to reduce the model bias in the electron
C     density calculated with model phases. SFCHECK produces the so
C     called total omit map by an automatic procedure. First, the
C     initial (Fobs, PHImodel) map is divided into N boxes. For each
C     box, the electron density in it is set to zero and new phases are
C     calculated from this modified map. A new map is calculated using
C     these phases and Fobs. This map contains the omit map for the
C     given box which is stored until the procedure is repeated for
C     all boxes. At the end, all the boxes with omit maps compose
C     the total omit map. Phases calculated from the total omit map
C     are combined with the initial phases. The whole procedure may
C     be repeated (keyword NOMIT). Note: it is time consuming!
C
C IV. Partional information
C
C     Program can use only one input file of coordinates or structure 
C     factors. In this case program gives information derived from
C     input file without local estimation.
C
C ==========================================================================
C
C   SFCHECK is an interactive program with the following input:
C
C 1. Do you want to have LOG-FILE /sfcheck.log/ ? /<N>/Y/:
C
C 2. Input file with Fobs (format  ASCII (CIF or PDB) or BLANC)') 
C         Type file name with extention or just CR /it means without this file/
C         Extention "dat" means BLANC file')
C    FILE_SF:              
C                         -  name of input ASCII file with PDB or CIF format 
C                                     or
C                            CIFile of blanc-system.
C
C 3. Input file with model (format PDB or CIF or BLANC)') 
C         Type file name with extention or just CR /it means without this file/
C         Extention "crd" means BLANC file, "cif" - CIFile')
C    FILE_C:
C                         - name of formatted file of coordinates
C                           / PDB or CIFile of model/
C                                      or 
C                           CIF-BLANC file of model
C
C #
C # Keywords:
C #
C # NOMIT               - number of cycles of omit procedure, 2 is a good 
C #                     choice. Note: omit procedure takes time!
C #
C #     Next keywords are necessary if there is only Fobs file and
C #     this file has not information about space group and cell parameters 
C #     In this case you must define cell parameters and space group name
C #     or space group number and setting 
C #
C # GROUP:   < >        - space group name, use capital letter
C # CELL: <0,0,0,0,0,0> - cell parameters: a,b,c,alpha,beta,gamma
C # NSG:     <0>        - space group number /from <1> to 230 /
C # SETT:    <2>        - setting /1 or 2,for monoclinic and trigonal
C #                       groups only/
C #
C #---  type "key_word  parameter(s)", for example "nomit 2" ---
C #---  and/or press "CR" to run program                     ---
C
C ==========================================================================
C
C   File formats.
C
C    1. Input PDB_file of coordinates
C
C       Input PDB_file of coordinates must contain the CRYST1 card with
C       the unit cell and the space group name.
C       Program can use the information from HEADER,SCALE,MTRIX,REMARK cards.
C
C    2. Input formatted file of structure factors
C
C       This file of structure factors must be in PDB-format or CIFile
C       which contains indices and structure factors or intensities.
C       (also simple formatted file with "h,k,l,!F!,sig(F)" or "h,k,l,!F!" 
C       and without titles is acceptable)
C
C       A. Example of a CIfile of structure factor amplitudes:
C
C         data_structure_9ins
C         _entry.id  9ins  
C         _struct.title ' insuline 9ins' 
C         _cell.length_a      100.000
C         _cell_length_b      100.000
C         _cell.length_c      100.000
C         _cell.angle_alpha    90.000
C         _cell.angle_beta     90.000
C         _cell.angle_gamma    90.000
C         _symmetry.space_group_name_H-M  'P 1 21 1'
C         loop_
C         _refln.index_h
C         _refln.index_k
C         _refln.index_l
C         _refln.F_meas_au
C         _refln.F_meas_au_sigma
C            2  3   4    12.3   1.2
C           -2 -3  -4    11.4   1.1
C          . . . . . . . . . . . . .
C
C               or just:
C
C         data_structure_9ins
C         loop_
C         _refln.index_h
C         _refln.index_k
C         _refln.index_l
C         _refln.F_meas_au
C         _refln.F_meas_au_sigma
C            2  3   4    12.3   1.2
C           -2 -3  -4    11.4   1.1
C           . . . . . . . . . . . . .
C
C          For intensities use:
C
C          _refln.intensity_meas 
C          _refln.intensity_sigma 
C
C       B. Example of a PDB file of structure factor amplitudes:
C
C       HEADER   R2SARSF   15-JAN-91
C       COMPND   RIBONUCLEASE SA (E.C.3.1.4.8) COMPLEX WITH 3'-*GUANYLIC ACID 
C       SOURCE   (STREPTOMYCES $AUREOFACIENS)
C       AUTHOR   J.SEVCIK,E.J.DODSON,G.G.DODSON
C       CRYST1  64.900   78.320   38.790  90.00  90.00  90.00 P 21 21 21    8
C       CONTNT   H,K,L,S,FOBS,SIGMA(FOBS)
C       FORMAT   (2(I3,2I4,2F7.0,F6.0,9X))
C       COORDS   2SAR
C       REMARK  1 TWO REFLECTIONS PER RECORD.
C       REMARK  2 DMIN=1.85, DMAX=16.28
C       CHKSUM  1 MIN H=0,MAX H=34,MIN K=0,MAX K=41,MIN L=0,MAX L=20
C       CHKSUM  2 TOTAL NUMBER OF REFLECTIONS=17346
C       CHKSUM  3 TOTAL NUMBER OF REFLECTION RECORDS=8673
C       CHKSUM  4 SUM OF FOBS=0.235499E+07
C         0   0   3     60      9    16           0   0   4    106    307    25
C         0   0   5    166     23    20           0   0   6    239    657    52
C         0   0   7    326      0    38           0   0   8    425    511    40
C       . . . . . . . . . . . . . . . . . . . . . .
C
C       C. Example of a simple formatted file of structure factor amplitudes 
C          which is assumed to contain H,K,L,F,sig(F):
C                   
C            2  3   4    12.3   1.2
C           -2 -3  -4    11.4   1.1
C           . . . . . . . . . . . . .
C
C           or without sig(F):
C
C            2  3   4    12.3  
C           -2 -3  -4    11.4  
C           . . . . . . . . . 
C
C      The length of file records must not exceed 80 characters.
C      The format of the records is free, e.g. data must be separated by
C      blancs. ( be careful - some PDB files do not satisfy this rule)  
C      The program uses the information about cell parameters and space
C      group from the coordinate file and ignores such information in
C      the structure factor file.
C
C ==========================================================================
C
C    Output files 
C
C      The output information is represented in the PostScript file:
C
C             sfcheck_<identifier>.ps
C 
C      A simple ASCII version of this file is in:
C
C             sfcheck.log 
C
C      The program produces a BLANC/CIF file of coordinates 
C 
C             sfcheck.crd 
C
C      The program creates:
C
C          a new formatted CIFile of Fobs: sfcheck.hkl
C
C          a file of density around model:   sfcheck_ext.dat
C          /CCP4 format for CCP4 distribution or BLANC format/
C
C      Other files have internal format of the BLANC program suite
C      (see file README by ftp from anonymous @ftp.yorvic.yorK.ac.uk) 
C      and can be used by programs of this suite.
C
C             sfcheck_fob.dat  - BLANC_Fobserved_file 
C             sfcheck_fmd.dat  - BLANC_Fmodel_file 
C             sfcheck_fsc.dat  - BLANC_Fmodel_scaling_file 
C             sfcheck_ph.dat   - BLANC_PHASE_file of the model
C             sfcheck_do.dat   - BLANC_observed_density_file
C             sfcheck_dm.dat   - BLANC_model_density_file
C
C ==========================================================================
C
C     Subroutine version of SFCHECK
C
C       It is possible to use subroutine SFCHECK instead of program.
C       Use all subroutines without "main_sfcheck.f" which just
C       prepares parameters for subroutine "sfcheck".
C
C      SUBROUTINE SFCHECK(MDOC,FILE_PDB,FILE_CIF,NOMIT
C     * ,GROUP,NGROUP,NSETT,ACELL,BCELL,CCELL,ALCELL,BECELL,GACELL
C     * ,LABEL,RESULT,RESULTA,RESULTB,IPRROW
C     * ,POOL,MEMORY,NCRDMAX,ISYM,IPRSYM,IERR)
C
C      input parameters:
C 
C      MDOC          -  =999 with  DOC-file: "sfcheck.doc",  
C      /integer*4/      if = -999 it means without this file.
C                          It must be 999 or -999 !!!!
C
C      FILE_PDB      -  name of input PDB_file 
C      /character*80/           or
C                       CIFile of blanc-system.
C
C      FILE_CIF      - name of formatted file of structure factors
C      /character*80/  / PDB or CIFile of structure factors/
C                               or 
C                      internal BLANC file of structure factors
C
C      NOMIT         - number of cycles of omit procedure
C      /integer*4/
C
C      ACELL,BCELL,CCELL    - cell parameters
C      ALCELL,BECELL,GACELL
C      /real*4/
C
C      GROUP         -  name of space group
C      /character*20/           
C
C      NGROUP        - number of space group
C      /integer*4/
C
C      NSETT         - setting
C      /integer*4/
C
C ---
C      LABEL         - for CCP4 version
C      /character LABEL(20)*30/
C
C      ISYM    - ISYM(5,3,IPRSYM) integer*2 array for cryst.symmetry operators 
C      /integer*2/       
C
C      IPRSYM  - dimension of integer*2 array ISYM(5,3,IPRSYM)
C      /integer*4/  maximal number of symmetry operators
C
C      NCRDMAX - maximal number of atoms.
C      /integer*4/
C
C      POOL    - real array POOL(MEMORY)
C      /real*4/
C
C      MEMORY  - dimension array POOL. 
C      /integer*4/   MEMORY = MAPMAX + (NCRDMAX/2)*5 , where MAPMAX - maximal
C                                                 size of XY-section ( NX*NY)
C
C      RESULT  - RESULT (IPRROW,21) real array.
C      /real*4/
C
C      RESULTA - RESULT (IPRROW,21) real array.
C      /real*4/
C
C      RESULTB - RESULT (IPRROW,21) real array.
C      /real*4/
C
C      IPRROW    must be = 21
C      /integer*4/ dimension of real array RESULT, RESULTA, RESULTB 
C
C               You need not to define the contents of
C               ISYM, POOL, RESULT, RESULTA, RESULTB 
C               Here is just reservation of memory.
C ---
C      output:
C
C         IERR          - signal of error, 0 means OK.
C         /integer*4/
C 
C ==========================================================================
C
C     Memory control parameters ( in main_sfcheck.f ):
C 
C         MEMORY - memory for densities, gradients, coordinates, ...
C         PARAMETER ( MEMORY=900000)
C         REAL      POOL(MEMORY)
C
C         NCRDMAX - maximal number of coordinates
C         PARAMETER ( NCRDMAX=32000)
C
C         IPRSYM - maximal number of symmetry operators
C         PARAMETER ( IPRSYM=48    )
C         INTEGER*2 ISYM(5,3,IPRSYM)
C 
C         ISYM    - integer*2 array for cryst.symmetry operators 
C         IPRSYM  - dimension of integer*2 array ISYM(5,3,IPRSYM)
C                   maximal number of cryst.symmetry operators.
C
C         MEMORY  - dimension array POOL. 
C
C                MEMORY = MAPMAX + (NCRDMAX/2)*5 , where MAPMAX - maximal
C                                                  size of XY-section (NX*NY)
C
C ==========================================================================
C
C   Installation.
C
C    Copy file sfcheck.tar.gz from ftp site: ftp.yorvic.york.ac.uk
C                                               (  user: anonymous
C                                                  cd pub/alexei    )
C          and uncompress it (`gunzip sfcheck.tar.gz')  
C
C   After untaring `sfcheck.tar' , you will get a sfcheck directory,
C   with src, doc, lib, and bin subdirectory. To build the executable,
C   go in src and then you have to option
C
C  1. `make all', the executable (sfcheck) will finish up in the bin
C      directory; providing the full pathname (.../sfcheck/bin/sfcheck) one 
C      can execute it from anywhere without having to define and environmental
C      variable.
C
C  2. `make ccp4' ( CCP4 distribution ) the executable (sfcheck) will
C      finish up in the bin directory; providing the full pathname 
C      (.../sfcheck/bin/sfcheck) one can execute it from anywhere 
C      without having to define and environmental variable, except
C      variable CLIB which defines directory of CCP4 libraries.
C  
C  3.  `make lnx` Linux distribution without ccp4.
C
C  4.  `make lnx_ccp4` Linux distribution with ccp4.
C
C      read also INSTALL file in sfcheck/
C
C ----------------------------------------------------------------------
C 
C
C    Independence on operating system:
C
C       There are only 2 subroutine depended on operating system
C       in the files: sfch_unix.f or sfch_linux.f
C
C
C     DISPL    - write message to terminal and stop cursor at the end of line.
C     CLOCK    - get date to --> array IH()
C
C      You need to uncomment corresponding operators in this subroutines.
C      For example:
C
C              SUBROUTINE DISPL(LINE)
C        C
C        C -P- DISPL - write message to terminal and stop cursor 
C        C             at the end of line.
C        C             NOTE : for Linux ( CLN ) cursor will not stop
C        C                    at the end of line.
C        C         
C              CHARACTER LINE*(*)
C              INTEGER*4 NL
C              CALL LENSTR(LINE,NL)
C              IF(NL.GT.79) NL=79
C        CVX   WRITE(*,'(''$'',A)')   LINE(1:NL)
C        CDP   WRITE(*,'('' '',A,$)') LINE(1:NL)
C        CMS   WRITE(*,'('' '',A,\)') LINE(1:NL)
C        CLN   WRITE(*,'('' '',A  )') LINE(1:NL)
C              RETURN
C              END
C
C      CVX - for VMS VAX 
C      CDP - for unix system
C      CMS - for MS-DOS
C      CLN - for Linux 
C
C      Current version is prepared for UNIX system.
C
C ---------------------------------------------------------------------
C
C    SFCHECK version for CCP4.
C
C    You can have CCP4 version of SFCHECK which can read MTZ file
C    and create file with extract density around model (format CCP4) 
C 
C 1. This possibility uses CCP4 libraries. 
C    You must define the path to this libraries by variable CLIB.
C    Give command: setenv CLIB <path_to_lib>
C
C 2. Keywords for reading MTZ file.
C
C       
C     #     Next keywords are necessary only for MTZ file
C     #
C     #  F:        < >       - label of F or F(+)')
C     #  SIGF:     < >       - label of sigma F or sigma F(+)')
C     #  F-:       < >       - label of F(+)')
C     #  SIGF-:    < >       - label of sigma F(-)')
C     #  FREE:     < >       - label of Free_flag')
C     #  I:        < >       - label of I or I(+)')
C     #  SIGI:     < >       - label of sigma I or  sigma I(+)')
C     #  I-:       < >       - label of I(-)')
C     #  SIGI-:    < >       - label of sigma I(-)')
C     
C ==========================================================================
C
C   Authors:     A.A.Vagin, J.Richelle, S.J.Wodak.
C
C   Reference:   A.A.Vaguine, J.Richelle, S.J.Wodak. SFCHECK: a unified set of 
C                procedure for evaluating the quality of macromolecular 
C                stracture-factor data and their agreement with atomic model.
C                Acta Cryst.(1999). D55, 191-205
C
C ==========================================================================




