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C
C TTBOXREF : Refines lattice parameters in image transform of tilted specimen.
C                          first created from TTBOX - 15 November 1990
C                          last modified - see versions below.
C
C        Version   2.00   15 Nov 1990  RH   Original changes from TTBOX/MMLATREF
C        Version   2.01   17 Nov 1990  RH   Extra format changes, annotation.
C
C    Incorporates several aspects in the refinement - similar to MMLATREF
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  Previous TTBOX versions  1.01    9 Dec 1985  RH
C  from which this program  1.02   14 Feb 1986  RH  SEGMNT option.
C  was created.             1.03   18 Nov 1987  JMB Rectangular images
C                           1.04   12 Jul 1988  RH  
C                           1.05   10 Sep 1988  RH  Increase TITLE to 68 bytes.
C                           1.06    2 Jan 1989  RH  ICTFBXMAX upped to 120, etc
C                           1.07   24 Jan 1989  RH  IQ=8 plotted as small dot.
C
C     DATACARDS ----------------------------------------------
C
C  0.   NCYCLES,FSHIFT   (*)
C
C  1.   FILIN -- full name of input file (.FFT)
C
C  2.   ISER,TITLE (I10,17A4)
C
C  3.   GENGRID   (A)
C
C  4.   GENPTS    (A)
C
C  5.   ISIZEX,ISIZEY,DSTEP,XMAG,CS,KVOLT   (*)
C
C  6.   DFMID1,DFMID2,ANGAST,TLTAXIS,TLTANGL   (*)
C
C  7.   NUMSPOT, NOH, NOK, NHOR, NVERT  (*)
C
C  9    RESMIN, RESMAX,  XORIG, YORIG, SEGMNT  (*)
C
C  10.  if GENGRID or GENPTS :          AX, AY, BX, BY    (*)
C
C  11.  if GENPTS                       : IH(I), IK(I)              (*)
C       if .not.GENGRID and .not.GENPTS : IH(I), IK(I), X(I), Y(I)  (*)
C
C
C     NCYCLES     number of cycles of lattice parameter refinement.
C     FSHIFT      fractional shift to be applied at end of each cycle.
C     ISER        serial number for run
C     TITLE       title to be printed
C     GENGRID     if YES generate grid from lattice points (1,0) & (0,1).
C     GENPTS      if YES individual spots requested & generated from grid
C                 if NO all spots within RESMIN to RESMAX generated.
C     ISIZEX,Y    size of image in x and y, checked against file-header.
C     DSTEP       densitometer stepsize in microns.
C     XMAG        magnification of micrograph.
C     CS          spherical aberration coefficient in mm.
C     KVOLT       microscope voltage in KV, used to calculate wavelength. 
C     DFMID1      defocus in one direction (underfocus +ve) 
C     DFMID2      defocus at 90-degs to above
C     ANGAST      direction for DFMID1 in degrees relative to x,y in transform.
C     TLTAXIS     direction of tiltaxis in degrees relative to x,y in transform,
C                   should be between -90 and +90 degrees.
C     TLTANGL     magnitude of tiltangle.
C                       (+ve for less underfocus at start of scan(y=0)).
C                       if tiltaxis is precisely parallel to y, then TLTANGL
C                       should be positive for less underfocus at x=0.
C     NUMSPOT     number of spots to be printed.
C     NOH, NOK    number of orders of spots in H & K directions to be generated.
C     NHOR, NVERT box size in grid units in horizontal & vertical directions,
C                 i.e. X & Y resp. ( up to 20 grid units in each
C                 direction).
C     RESMIN, RESMAX inner & outer resolution limits in Angstroms within which
C                        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     SEGMNT      segment of reciprocal space within which spots
C                 must fall to be include in this run. +/- 90
C                 includes all spots, +45 is half data near tiltaxis
C                 -45 is half perpendicular to tilt axis.
C     AX,AY,BX,BY coordinates in grid units of 1,0 & 0,1 spots
C                 respectively.
C     IH, IK      indices of individual spots required.
C     X, Y        coordinates of individual spots required.
C
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C