C   MMLATREF : Refinement of lattice parameters for maximum amplitude.
C    First created from MMBOX -- 16.12.86  RH
C    Last modified            -- 24.12.86  RH
C
C    Incorporates several aspects in the refinement
C       1. Maximises sum of sinc-fitted intensities.
C       2. Uses weighted coefficients -- 1/(rmsbk**2+ampsinc**2)
C               this should maximise the number of spots with IQ>=7
C       3. Matrix diagonal has constant added to it to stabilise refinement when
C               transform is very strong and clean --- this may mean that shifts
C               greater than 1.0 will be needed if the data is very noisy.
C                                                 (eg. at high resolution)
C       4. Summary table printed out at end to judge progress.
C       5. May be mainly good for getting just a little extra after UNBENDING.
C       6. Present sinc fit is just over 2x2 box around spot centre ... this is
C               thought to be insignificantly different from any bigger box.
C
C      NNBOX prints out amplitudes & phases in N * N boxes from a 
C      Fourier transform
C
C  DATA:
C
C       FILIN
C
C       ISER,TITLE (I10,15A4)
C
C       GU     (A)
C
C       GENGRID(A)
C
C       GENPTS (A)
C
C       IPIXEL, IOUT,NUMSPOT, NOH, NOK, NHOR, NVERT  (*)
C
C       FILOUT only if IOUT.NE.0
C
C       RINNER, ROUTER, XORIG, YORIG  (*)
C
C       NCYCLES, FSHIFT, ILIST (*)
C
C  if GENGRID :
C
C       AX, AY, BX, BY (*)
C
C  if .not. GENGRID :
C
C       IH(I), IK(I), X(I), Y(I)  (*)
C
C
C     ISER        serial number for run to be printed & output on IOUT.
C     TITLE       title to be printed & output on unit IOUT.
C     GU          if YES work in grid units, otherwise in mm.
C     GENGRID     if YES generate grid from lattice points (1,0) & (0,1)
C     GENPTS      if YES individual spots requested & generated from grid
C     IPIXEL      pixel size only used if .not.GU 
C     IOUT        output unit number for serial number and title, then
C                  IH,IK,A,P,IQ terminated with IH=100.
C     NUMSPOT     number of spots to be printed, if 0 defaults to 20.
C     NOH, NOK    number of orders of spots in H & K direcions
C     NHOR, NVERT box size in mm or grid units in horizontal &
C                 vertical directions,
C                 i.e. X & Y resp. ( up to 20 grid units in each
C                 direction).
C     RINNER, ROUTER inner & outer radius in mm or grid units within
C                    which spots (centre of box) must fall
C     XORIG, YORIG X & Y phase origin shifts to be added to those
C                  added to those read in on the transform
C     NCYCLES     number cycles of lattice parameter refinement to do.
C     FSHIFT      fractional shifts to be applied in lat. param. refn.
C     ILIST       if 0, abbreviated listing, if 1 full listing printed.
C     AX,AY,BX,BY coordinates in mm or grid units of 1,0 & 0,1 spots
C                 respectively
C     IH, IK      indices of individual spot
C     X, Y        coordinates of individual spot.
C
C****************************************************************************
C