2.18                      *******************
                                  * IMPORT WRITE-UP *
                                  *******************
        
           IMPORT is a program which allows the user to enter the PHASES 
        package with externally derived phase information. It is generally 
        used when one wants to bypass the PHASIT program, i.e. phases and 
        Hendrickson-Lattman coefficients are computed via some external 
        program, and one wants to use this phase information within the PHASES 
        package, often for solvent flattening or phase combination with a 
        partial structure. The program is interactive and prompts for the 
        names of input and output files. It then reads the externally prepared 
        reflection file, converts the indices, phase and Hendrickson-Lattman 
        coefficients to correspond to the reflection in the "standard" PHASES 
        asymmetric unit, identifies reflections with restricted phases, and 
        writes the information in a PHASIT style file. This output file can be 
        used within the package wherever a PHASIT file could be used, i.e. in 
        FSFOUR, MISSNG, BNDRY, MRGDF, MRGBDF, RD31 etc.  
        
                                   ***** FILES *****
        
        The input file should be an ASCII (formatted) file with each record
        containing the following data:
        
             H, K, L, FOBS, FOM, PHI, A, B, C, D
                                       
             where
        
             H,K,L   = Miller indices 
        
             FOBS    = Native structure factor amplitude
        
             FOM     = Figure of merit
        
             PHI     = Best (centroid) phase, in degrees
        
             A,B,C,D = Hendrickson-Lattman coefficients for phase probability
                       distribution
        
        
        The file is read in free format, i.e. items must be separated by at 
        least one blank space or comma. The indices are read as Fortran 
        INTEGERS whereas all other data are read as REALS.  
        
        
        
        The output PHASIT style binary file contains records with
        
             H, K, L, FMFO, FO, PHIBEST, IPRAB, IPRCD, MK, FM
        
             where
         
             H,K,L    =  Miller indices  
            
             FMFO     =  Figure of merit weighted structure factor amplitude
                         (either FOM * FP   or  FOM * F+)
            
             FO       =  Observed structure factor amplitude (either FP  or F+)
            
             PHIBEST  =  Best (centroid) phase, in degrees.
            
             IPRAB       Hendrickson-Lattman coefficients A,B,C,D for the phase
                     =   probability distribution used, packed two per word as 
             IPRCD       (IFIX(A*100)+16384)*32768 + IFIX(B*100)+16384  and
                         (IFIX(C*100)+16384)*32768 + IFIX(D*100)+16384
            
             MK       =  Restricted phase indicator.  For general reflections
                         MK=1,  for centric reflections MK > 1 and one of the
                         allowed phase values is (MK-1)*15 degrees (the other
                         possibility is 180 degrees away).
            
             FOM      =  Figure of merit associated with PHIBEST and used for
                         weighting.
        
        See the PHASIT write-up for more information