####################################################################

Main changes made after version 1.6:

1. A bug in the hexagonal lattice parameters refinement is fixed.

2. The Hall symbol interpretation is corrected. Only the Hall symbols from
   SGSY.inc are treated properly now.

3. Some improvements are made in the CIF import-export routines of DDMap.

####################################################################

Main changes made after version 1.5:

1. Over 100 additional space group settings are added, covering all the variants
   found in the ICSD.

2. The convolution interval assignment procedure is modified. It includes now an
   alternative algorithm based on the correlational statistics for data with
   unknown or unreliable intensity variances.

3. A bug in the hkl selection procedure is fixed that could lead to surplus
   reflections for certain symmetries.

4. The hexagonal symmetry restrictions for the 4-th rank strain broadening
   tensor are corrected.

5. DDM-R_exp calculation is set right.

####################################################################

Main changes made after version 1.4:

1. Hall notations are allowed by putting HALL before the space group symbol.

2. The derivatives for the Lorentzian part of TCH pV profile function (NPROF=7)
   are corrected that made its refinement more stable.
  
3. Systematic absences filtering is added to the extended reflection generation
   routine for LAUE=1.

####################################################################

Main changes made after version 1.3:

1. The space group interpretation and reflection generation routines were
   changed to more flexible and reliable ones. The rhombohedral setting and
   the acentric origin choice 1 are allowed.

2. The symmetry restrictions on all parameters are imposed automatically by
   the program.

3. The symmetry operators may be output to CIF file by setting LSYM flag to 1.

4. The number of refinement cycles MCYCLE starts from 0 (not from 1). 

5. Setting the maximal number of refined parameters MAXS to 0 makes all
   parameters with nonzero codewords refinable.

6. In the input file supplementary lines for excluded regions, extra scattering
   coeffitients and background extrapolation are repositioned (see DDMguide).

7. Output and auxiliary files are renamed to have ddm_ prefix.

####################################################################

Main changes made after version 1.2:

1. DDMap utility is added. This program reads crystal data and structure
   factors with (optional) phases from CIF file, calculates Fourier and
   Patterson maps including the Symmetry and Image minimum functions and
   allows viewing manually chosen sections of the 3D density map. It
   also generates GRD-files readable by 3D viewers such as MCE
   [http://www.vscht.cz/min/mce/] and Vesta
   [http://www.geocities.jp/kmo_mma/crystal/en/vesta.html].
   The structure model may be built/modified within DDMap by adding/removing
   atoms.

2. New weighting scheme is added that is chosen now by IWGHT flag.

3. New asymmetry parameter P2 responsible for the lattice-gradient effect is
   added.

4. Holes in the sequence of numbered codewords are removed automatically by
   the program. Setting MAXS to -1 removes all refinement flags.

5. An automatic procedure for the scale factor (SF) estimation is added.
   It is called when SF for a selected phase is set to zero.

6. The CIF-output is directed to a single file ddm_cif.cif.

####################################################################

Main changes made after version 1.1:

1. The observed structure factors can be written to CIF file if IFUR flag
   is set to 2. This allows importing such CIF file into other programs
   (e. g. Crystals available from http://www.xtl.ox.ac.uk/crystals.html)
   for further calculations and analysis of Fourier and Patterson maps.
   Note that Crystals can generate files readable by 3D MarchingCubes
   Fourier Map viewer (MCE).

2. The atom site multiplicity can be automatically calculated by the program
   when it is set to -1 (see template.ddm in TEMPLATE folder). 

3. The strain anisotropy may be applied to either Lorentzian or Gaussian
   component of the TCH pseudo-Voigt profile function depending on the
   sign of IAN3 flag.

4. The size of some arrays is increased in order to allow more reflections
   and overlaps.

####################################################################

Changes made after version 1.03:

1. The command line is changed.

2. The data file name is read from the Parameters file and the
   output listing file name is predefined as 'ddm_out.txt'.

3. The program package now includes a configuration for the
   Programmer's File Editor (PFE) to facilitate integrating DDM with
   graphical utilities such as Winplotr and a structure viewer.

4. New interval-dependent DDM weighting scheme is added, which may be
   advantageous for data with minor systematic errors

####################################################################

Changes made after version 1.02:

1. Quantitative phase analysis calculations are added.

2. The directions of the preferred orientation ellipsoid principal axes
   are estimated.

3. Beside the reliability factor R-DDM, a simplified weighted R-factor
   DDM-R_w and its expected value DDM-R_exp are now output.

4. New parameter BKCURV is added (see the program guide).

####################################################################

Changes made after version 1.01:

1. The 4-th rank tensor for anisotropic strain broadening is added.

2. The use of the anisotropic broadening terms for TCH pseudo-Voigt profile
   function is corrected.

3. The correction for peak shift due to sample transparency is replaced by
   the asymmetry-related peak shift correction.

4. The calculations of the average crystallite diameter and its dispersion
   are modified based on empirical approximations derived from fitting
   TCH-pV function to simulated profiles for the model of spherical
   crystallites with different size distribution dispersions. 
