John W. Campbell
This class provides some static methods to perform selected crystallographic
calculations. These include methods for converting between detector and
reciprocal lattice coordinates, setting up crystallographic matrices and
predicting reflections for Rotation and Laue images.
Note: Other useful crystallographic calculation methods are included in
the crystallographic objects with which they are associated e.g.
JdlCell - Reciprocal/real cell conversions
JdlSymmetry - Handling space group symmetry
JdlDistortionCorrections - Making detector coordinate distortion
corrections
Class and methods:
Class Details
Accessible Fields
Detector and Reciprocal Lattice
Crystal Setting Methods
Get nodal indices
Predict Rotation Reflections
Unique Reflections
Predict Laue Spots
Cell Parameters
- Package:
- Jdl.JdlPX;
- Class name:
- JdlCrystalCalculations
- Class definition:
- public class JdlCrystalCalculations
- Extends:
- Object
- Implements:
- none
- Actions:
- none
The following accessible fields have been defined:
- public final static int FLAT
- Detector geometry definition: flat.
- public final static int CYLINDRICAL
- Detector geometry definition: cylindrical.
- public final static double DTOR
- Conversion factor - degrees to radians.
- public final static double RTOD
- Conversion factor - radians to degrees.
This section has methods to convert between detector coordinates and
reciprocal lattice coordinates. Note that the JdlPositionedDetector class
has versions of these methods which make use of some internally stored data.
Methods:
Reciprocal lattice to detector - reciprocalLatticeToDetector
Detector to reciprocal lattice - detectorToReciprocalLattice
Convert mm to rasters - mmToRasters
Convert rasters to mm - rastersToMM
This method calculates ideal detector coordinates (xd, yd MOSFLM convention)
in mm from the pattern centre from a set of reciprocal lattice
coordinates for a reflection. Methods for applying distortion corrections
may be found in the JdlDistortionCorrections class.
- Method Definition:
- public static JdlXY reciprocalLatticeToDetector (double[] xr, double ctod, JdlVec s0, Jdl3x3 ddinv, JdlVec dn, int dgeom)
- Parameters List:
- xr
- The reciprocal lattice coordinates xr[3].
- ctod
- The crystal to detector distance in mm.
- s0
- The beam vector.
- ddinv
- The inverse of the detector orientation matrix.
- dn
- The detector normal vector.
- dgeom
- Detector geometry:
= 0, Flat
= 1, Cylindrical (cylinder axis along second local axis)
(May use FLAT or CYLINDRICAL)
- Method Return:
-
The ideal detector coordinates in mm (from the centre)
JdlXY.x is coordinate along first local axis (e.g. xd), JdlXY.y is coordinate
along the second local axis (e.g. yd). Note: For a flat detector it may
return null if reflection could not be recorded on even a very large detector.
It will also return null for an unknown detector geometry.
This method calculates reciprocal lattice coordinates for a reflection from
the ideal dectector coordinates in mm from the pattern centre. To get
'ideal' detector coordinates from 'real' coordinates see the
JdlDistortionCorrections class.
- Method Definition:
- public static JdlVec detectorToReciprocalLattice(double xd, double yd, JdlVec s0, Jdl3x3 dd, double dst2)
- Parameters List:
- xf
- The ideal detector 'x' coordinate in mm. (MOSFLM convention).
- yf
- The ideal detector 'y' coordinate in mm.
- s0
- The beam vector.
- dd
- The detector orientation matrix.
- dst2
- (d*)**2 for the reflection. Required for the Laue case but may
give zero for the monochromatic case.
- Method Return:
-
Returns the reciprocal lattice coordinates in a 3 element vector.
This method converts a set of detector coordinates in mm relative to
the pattern centre to rasters in the image.
- Method Definition:
- public static JdlXY mmToRasters (JdlXY xy, double ax1_cen, double ax2_cen, double pixsiz_ax1, double pixsiz_ax2)
- Parameters List:
- xy
- The coordinates in mm from the pattern along the first
local axis in xy.x and second local axis xy.y.
- ax1_cen
- Image centre position in rasters along local axis 1.
- ax2_cen
- Image centre position in rasters along local axis 2.
- pixsiz_ax1
- Pixel size in mm along local axis 1.
- pixsiz_ax2
- Pixel size in mm along local axis 2.
- Method Return:
-
The coordinates converted to rasters.
This method converts a set of detector coordinates from image rasters
to mm relative to the pattern centre.
- Method Definition:
- public static JdlXY rastersToMM (JdlXY xy, double ax1_cen, double ax2_cen, double pixsiz_ax1, double pixsiz_ax2)
- Parameters List:
- xy
- The coordinates in image rasters along the first
local axis in xy.x and second local axis xy.y.
- ax1_cen
- Image centre position in rasters along local axis 1.
- ax2_cen
- Image centre position in rasters along local axis 2.
- pixsiz_ax1
- Pixel size in mm along local axis 1.
- pixsiz_ax2
- Pixel size in mm along local axis 2.
- Method Return:
-
The coordinates converted to mm from the pattern centre.
This section has methods to set up a B-matrix or an Orienatation Matrix and
to perform cell and setting related functions.
Methods:
Set B-matrix - setBMatrix
Set B-matrix - setBMatrix
Set orientation matrix - setOrientationMatrix
Set orientation matrix - setOrientationMatrix
Cell orthogonalisation - setOrthogonalisationMatrix
Get cell vectors - getCellVectors
Get third vector - getThirdVector
Get missetting angles - getMissettingAngles
Set up a crystallographic B-Matrix.
- Method Definition:
- public static Jdl3x3 setBMatrix (JdlCell cell, double wavelength)
- Parameters List:
- cell
- The real cell parameters.
- wavelength
- The wavelength in Angstroms.
- Method Return:
-
The B-Matrix.
Set up a crystallographic B-Matrix.
- Method Definition:
- public static Jdl3x3 setBMatrix (double[] cell, double wavelength)
- Parameters List:
- cell
- A six element array containing the real cell parameters in
Angstroms and degrees.
- wavelength
- The wavelength in Angstroms.
- Method Return:
-
The B-Matrix.
Set up crystal orientation matrix.
- Method Definition:
- public static Jdl3x3 setOrientationMatrix (JdlCell cell, double wavelength, double[][] umat, double phi1, double phi2, double phi3)
- Parameters List:
- cell
- The cell as a JdlCell Object.
- wavelength
- The wavelength in Angstroms.
- umat
- The 3x3 U-matrix.
- phi1
- Rotation around the laboratory 'X' axis - missetting angle.
- phi2
- Rotation around the laboratory 'Y' axis - missetting angle.
- phi3
- Rotation around the laboratory 'Z' axis - missetting angle.
- Method Return:
-
Returns the required orientation matrix.
Set up crystal orientation matrix.
- Method Definition:
- public static Jdl3x3 setOrientationMatrix (double[] cell, double wavelength, double[][] umat, double phi1, double phi2, double phi3)
- Parameters List:
- cell
- A six element array containing the real cell parameters in
Angstroms and degrees.
- wavelength
- The wavelength in Angstroms.
- umat
- The 3x3 U-matrix.
- phi1
- Rotation around the laboratory 'X' axis - missetting angle.
- phi2
- Rotation around the laboratory 'Y' axis - missetting angle.
- phi3
- Rotation around the laboratory 'Z' axis - missetting angle.
- Method Return:
-
Returns the required orientation matrix.
This method returns the standard orthogonalisation matrix for
a real unit cell.
- Method Definition:
- public static Jdl3x3 setOrthogonalisationMatrix(JdlCell cell)
- Parameters List:
- cell
- The real cell.
- Method Return:
-
The standard orthogonalisation matrix.
This method gets the cell vectors in the standard orthogonal frame and
also returns additional cell based vectors if required.
- Method Definition:
- public static JdlVec[] getCellVectors(JdlCell cell, int latt)
- Parameters List:
- cell
- The real cell.
- latt
- Lattice type (1-7 for P, A, B, C, I, F, R) or 0 for
cell vectors only. Give 1 for primitive cell or to return
main cell vectors + vectors, 011, 101, 110, and 111. For values 2-6,
vectors from the origin to the centered positions will also be
returned.
- Method Return:
-
Array of three vectors for the real cell parameters a, b and c
respectively + related vectors.
This method calculates a third cell vector given two cell vectors, the
length of the third vector and the angles between the third vector and the
first two cell vectors. </br>
If vectors for A and B are known then
vect1 = the A vector, vect2 = the B vector, ang1 = beta, ang2 = alpha </br>
If vectors for B and C are known then
vect1 = the B vector, vect2 = the C vector, ang1 = gamma, ang2 = beta </br>
If vectors for A and C are known then (reverse order to get right handed set)
vect1 = the C vector, vect2 = the A vector, ang1 = gamma, ang2 = alpha </br>
- Method Definition:
- public static JdlVec getThirdVector(JdlVec vec1, JdlVec vec2, double ang1, double ang2, double vlen, double tol)
- Parameters List:
- vect1
- The vector for the first cell axis.
- vect2
- The vector for the second cell axis.
- ang1
- The required angle between the third vector and the first vector.
- ang1
- The required angle between the third vector and the second vector.
- vlen
- The length of third vector.
- tol
- The first angle is used explicitly in the calculation of the
third vector but then a rotation around vect1 is determined by an iterative
procedure to within 'tol' degrees (e.g. 0.001).
- Method Return:
-
Returns the required third vector.
Get the crystal missetting angles from the standard setting for a crystal
given a set of found cell vectors with respect to the laboratory axes (assumes
a* along X and b* in XY plane (Wonacott convention). The method incorporates
coding by M. Elder
- Method Definition:
- public static double[] getMissettingAngles(JdlVec vec1, JdlVec vec2, JdlVec vec3, Jdl3x3 umat)
- Parameters List:
- vec1
- First cell vector
- vec2
- Second cell vector
- vec3
- Third cell vector
- umat
- The 'U' matrix
- Method Return:
-
Array containing the three missetting angles PHI_X, PHI_Y and
PHI_Z in degrees.
This section has a method to calculate a set of nodal indices for a
(Laue) reflection.
Methods:
Get nodal indices - getNodalIndices
Calculate a set of nodal indices from a set of reflection indices.
- Method Definition:
- public static void getNodalIndices(int[] ihkl, int[] nhkl)
- Parameters List:
- ihkl
- 3 element array containing the input indices.
- nhkl
- 3 element array in which the nodal indices will be returned.
This section has methods to predict reflections for a rotation
image for the monochromatic rotation method. It is closely based on code
from Oscgen & Madnes by Peter Brick, Andrew Leslie, Jean Claude Thierry,
Alan J. Wonacott and J. W. Pflugrath from the Reeke prediction coded by
R.M. Sweet. The input parameters may be derived from a Diffraction Data Module
object, objects containing the required detector and crystal data or
from a full and explicit list of the required parameters. In each case,
the actual output is handled using an object implementing the
JdlRotReflOutputHandler interface so that the method is not tied to
any particular output reflection list format. Note that the prediction
methods handle systematic absences as determined by the lattice type
but the user supplied output object should handle any additional absences.
Quick options are available which predict reflections but do not distinguish
between fully and partially recorded reflections.
Methods:
Predict using DDM - predictRotationReflections
Predict using DDM - predictRotationReflections
Predict reflections - predictRotationReflections
Predict reflections - predictRotationReflections
Predict single reflection - predictSingleReflection
This is the first of two methods to predict rotation reflections from
the parameters stored in a JdlDiffractionDataModule object. The required
image is selected via the set number and image number.
- Method Definition:
- public static boolean predictRotationReflections ( JdlDiffractionDataModule ddm, int iset, int irange, int imgnum, boolean quick, JdlRotReflOutputHandler refout)
- Parameters List:
- ddm
- The JdlDiffractionDataModule object containing the detector and
crystal data.
- iset
- The set number within the Diffraction Data Module.
- irange
- The rotation range number.
- imgnum
- The number of the image (within the requested rotation
range) for which the prediction is to be carried out.
- quick
- If set to true a quick prediction will be carried out with
fewer details being calculated for each reflection. If false the full
detailed prediction will be performed (see the parameters of the
JdlRotReflOutputHandler outputPredictedReflection(..) method for details
of the items which are calculated.
- refout
- An object implementing the JdlRotReflOutputHandler interface
to output the reflection data and handle systematic absences other than
those determined from the lattice type.
- Method Return:
-
Returns the error flag set by the 'refout' object.
This is the second of two methods to predict rotation reflections from
the parameters stored in a JdlDiffractionDataModule object. The required
image is selected via the set number and a rotation angle range.
- Method Definition:
- public static boolean predictRotationReflections ( JdlDiffractionDataModule ddm, int iset, int imgnum, double rotimg_start, double rotimg_end, boolean quick, JdlRotReflOutputHandler refout)
- Parameters List:
- ddm
- The JdlDiffractionDataModule object containing the detector and
crystal data.
- iset
- The set number within the Diffraction Data Module.
- imgnum
- The number of the image (within the requested rotation
range) for which the prediction is to be carried out.
- rotimg_start
- The start angle for the rotation range in degrees.
- rotimg_end
- The end angle for the rotation range in degrees.
- quick
- If set to true a quick prediction will be carried out with
fewer details being calculated for each reflection. If false the full
detailed prediction will be performed (see the parameters of the
JdlRotReflOutputHandler outputPredictedReflection(..) method for details
of the items which are calculated.
- refout
- An object implementing the JdlRotReflOutputHandler interface
to output the reflection data and handle systematic absences other than
those determined from the lattice type.
- Method Return:
-
Returns the error flag set by the 'refout' object.
This method predicts reflections using data stored in objects containing
details of the detector and crystal. The rotation range is also specified.
- Method Definition:
- public static boolean predictRotationReflections ( JdlPositionedDetector posdet, JdlPositionedCrystal poscrys, double rotimg_start, double rotimg_end, boolean quick, JdlRotReflOutputHandler refout)
- Parameters List:
- posdet
- A JdlPositionedDetector object containing details of the
positioned detector, gonioneter and X-ray source.
- poscrys
- A JdlPositionedCrystal containing details of the crystal cell,
symmetry and setting.
- rotimg_start
- The start angle for the rotation range in degrees.
- rotimg_end
- The end angle for the rotation range in degrees.
- quick
- If set to true a quick prediction will be carried out with
fewer details being calculated for each reflection. If false the full
detailed prediction will be performed (see the parameters of the
JdlRotReflOutputHandler outputPredictedReflection(..) method for details
of the items which are calculated.
- refout
- An object implementing the JdlRotReflOutputHandler interface
to output the reflection data and handle systematic absences other than
those determined from the lattice type.
- Method Return:
-
Returns the error flag set by the 'refout' object.
This version specifies the individual parameters explicitly.
- Method Definition:
- public static boolean predictRotationReflections (double rots, double rote, double[][] aprs, double[][] apre, double[][] aprsx, double[][] aprex, double[] s0, double[] scax, double dst2mx, double dstpl2, int nwmax, int latt, int isyn, double divh_half, double divv_half, double eta_half, double delamb, double delcor_half, int iax_h, int iax_v, boolean quick, JdlRotReflOutputHandler refout)
- Parameters List:
- rots
- Rotation start angle in degrees.
- rote
- Rotation end angle in degrees.
- aprs[3][3]
- Orientation matrix at start of rotation range.
- apre[3][3]
- Orientation matrix at end of rotation range.
- aprsx[3][3]
- Orientation matrix at start of range extended (in negative
direction) by maximum possible reflection width.
- aprex[3][3]
- Orientation matrix at end of range extended (in positive
direction) by maximum possible reflection width.
- s0[3]
- Beam direction vector wrt laboratory axes.
- scax[3]
- Scan axis direction vector wrt laboratory axes.
- dst2mx
- Maximum value of (dstar)**2.
- dstpl2
- Maximum value of (dstar)**2 allowing for a bit extra for
determining overlaps at edge of image.
- nwmax
- Maximum no. of images over which a spot may be spread.
- latt
- Lattice type flag 1-7 for p, a, b, c, i, f, r for lattice
based systematic absences. User must handle other space group specific
absences in user supplied reflection output object.
- isyn
- Source type flag =0 lab source, =1 synchrotron.
- divh_half
- Horizontal beam divergence (half-width, radians).
- divv_half
- Vertical beam divergence (half-width, radians).
- eta_half
- Mosaicity (half_width, radians).
- delamb
- Dispersion (delta(lambda)/lambda).
- delcor_half
- Correlated dispersion term (only used for synchrotron)
(half-width, radians).
- iax_h
- No. of horizontal axis in laborarory system (1=x, 2=y, 3=z).
- iax_v
- No. of vertical axis in laborarory system (1=x, 2=y, 3=z).
- quick
- Logical flag; If true, do a quick analysis which does
not distinguish between fulls & partials and which does not calculate
relection widths; If false, do the full detailed prediction.
- refout
- An object implementing the JdlRotReflOutputHandler interface
to output the reflection data and handle systematic absences other than
those determined from the lattice type.
- Method Return:
-
Returns the error flag set by the 'refout' object.
This method predicts the position for a single reflection (rotation method)
based on the detector parameters and crystal setting.
- Method Definition:
- public static JdlPredictedReflection predictSingleReflection ( int h, int k, int l, JdlPositionedDetector posdet, Jdl3x3 mat, double rotmid, JdlDistortionCorrections distor)
- Parameters List:
- h
- The 'h' index.
- k
- the 'k' index.
- l
- the 'l' index.
- posdet
- The positioned dectector object for the detector setting.
- mat
- The crystal orientation matrix.
- rotmid
- The mid angle of the rotation range.
- distor
- A distortions corrections object (may be null if distortion
corrections are not to be applied).
- Method Return:
-
A JdlPredictedReflection object with details of the predicted
reflection (details set as described for a 'quick' prediction).
This section has a method to generate a list of the unique reflections
for a given cell and space group.
Method:
Find unique limits - getUniqueIndexLimits
Generate unique reflections - generateUniqueReflections
Generate unique reflections - generateUniqueReflections
This method finds the limits for h, k and l for a Laue group, cell
and resolution limit (From CCP4 code).
- Method Definition:
- public static void getUniqueIndexLimits(int nlaue, JdlCell cell, double resmax, int[] hkl_lims)
- Parameters List:
- nlaue
- The Laue group number.
- cell
- The cell.
- resmax
- Resolution limit.
- hkl_lims
- A six element array returning hmin, hmax, kmin, kmax, lmin
and lmax limits.
This method generates the unique list of reflections for a given cell,
space group and wavelength within given resolution limits. The resolution
limits may be given in either order.
- Method Definition:
- public static int generateUniqueReflections(JdlSymmetry symm, JdlCell cell, double wave, double resmin, double resmax, JdlUnqReflOutputHandler refout)
- Parameters List:
- symm
- The symmetry (full symmetry must be defined)
- cell
- The real cell parameters.
- wave
- The wavelength in Angstroms.
- resmin
- The minimum resolution in Angstroms.
- resmax
- The maximum resolution in Angstroms (or 0.0 if no limit).
- refout
- An object implementing the JdlUnqReflOutputHandler interface
to output the reflection data.
- Method Return:
-
The number of reflections generated (0 if symmetry not defined or
other invalid parameters given)
This method generates the unique list of reflections for a given cell,
space group and wavelength within given resolution limits. The resolution
limits may be given in either order and the other parameters are derived,
in this version of the method, from a Diffraction Data module object.
- Method Definition:
- public static int generateUniqueReflections(JdlDiffractionDataModule ddm, int iset, int img, double resmin, double resmax, JdlUnqReflOutputHandler refout)
- Parameters List:
- ddm
- JdlDiffractionDataModule object containing the cell, symmetry
and wavelength.
- iset
- Set number within the JdlDiffractionDataModule object.
- img
- The (reference) image number - normally 1.
- resmin
- The minimum resolution in Angstroms.
- resmax
- The maximum resolution in Angstroms (or 0.0 if no limit).
- refout
- An object implementing the JdlUnqReflOutputHandler interface
to output the reflection data.
- Method Return:
-
The number of reflections generated (0 if symmetry not defined or
other invalid parameters given)
This section has methods to predict spots for Laue image.
Methods:
Predict Laue using DDM - predictLaueSpots
Predict Laue using DDM - predictLaueSpots
Predict Laue spots - predictLaueSpots
Predict Laue spots - predictLaueSpots
This is the first of two methods to predict Laue spots from
the parameters stored in a JdlDiffractionDataModule object. The required
image is selected via the set number and image number.
- Method Definition:
- public static boolean predictLaueSpots (JdlDiffractionDataModule ddm, int iset, int irange, int imgnum, JdlLaueSpotOutputHandler refout)
- Parameters List:
- ddm
- The JdlDiffractionDataModule object containing the detector and
crystal data.
- iset
- The set number within the Diffraction Data Module.
- irange
- The rotation range number.
- imgnum
- The number of the image (within the requested range) for which
the prediction is to be carried out.
- refout
- An object implementing the JdlLaueSpotOutputHandler interface
to output the spot data and handle systematic absences other than
those determined from the lattice type.
- Method Return:
-
Returns the error flag set by the 'refout' object.
This is the second of two methods to predict Laue spots from
the parameters stored in a JdlDiffractionDataModule object. The required
image is selected via the set number and a rotation angle.
- Method Definition:
- public static boolean predictLaueSpots (JdlDiffractionDataModule ddm, int iset, int imgnum, double rot_ang, JdlLaueSpotOutputHandler refout)
- Parameters List:
- ddm
- The JdlDiffractionDataModule object containing the detector and
crystal data.
- iset
- The set number within the Diffraction Data Module.
- imgnum
- The number of the image (within the requested range) for which
the prediction is to be carried out.
- rot_ang
- The rotation angle for the image in degrees.
- refout
- An object implementing the JdlLaueSpotOutputHandler interface
to output the spot data and handle systematic absences other than
those determined from the lattice type.
- Method Return:
-
Returns the error flag set by the 'refout' object.
This method predicts Laue spots using data stored in objects containing
details of the detector and crystal. The rotation (spindle) angle is also
specified.
- Method Definition:
- public static boolean predictLaueSpots (JdlPositionedDetector posdet, JdlPositionedCrystal poscrys, double rot_ang, JdlLaueSpotOutputHandler refout)
- Parameters List:
- posdet
- A JdlPositionedDetector object containing details of the
positioned detector, gonioneter and X-ray source.
- poscrys
- A JdlPositionedCrystal containing details of the crystal cell,
symmetry and setting.
- rot_ang
- The start angle for the rotation range in degrees.
- refout
- An object implementing the JdlLaueSpotOutputHandler interface
to output the spot data and handle systematic absences other than
those determined from the lattice type.
- Method Return:
-
Returns the error flag set by the 'refout' object.
This version specifies the individual parameters explicitly.
- Method Definition:
- public static boolean predictLaueSpots(double[][] a, double wmin, double wmax, double dmin, int latt, JdlLaueSpotOutputHandler refout)
- Parameters List:
- a[3][3]
- The orientation matrix for the curre3nt crystal setting.
- wmin
- The minimum wavelength for the prediction.
- wmax
- The maximum wavelength for the prediction.
- dmin
- The minimum 'd' spacing limit.
- latt
- Lattice type flag 1-7 for p, a, b, c, i, f, r for lattice
based systematic absences. User must handle other space group specific
absences in user supplied reflection output object.
- refout
- An object implementing the JdlLaueSpotOutputHandler interface
to output the spot data and handle systematic absences other than
those determined from the lattice type.
- Method Return:
-
Returns the error flag set by the 'refout' object.
This section has methods to set convert a set of cell parameters between
the full set of six and a contracted set containing a single
entry for each unique variable cell parameter.
Methods:
Contract cell - contractCell
Expand cell - expandCell
Unique cell parameters - numberUniqueCellParameters
This method converts the full set of cell parameters (real or reciprocal)
to a contracted set.
- Method Definition:
- public static double[] contractCell(double[] cell, int isys)
- Parameters List:
- cell
- The six cell parameters (a, b, c, alpha, beta, gamma.
- isys
- The crystal system number 1-7.
- Method Return:
-
Returns an array of six values being the unique variable
cell parameters folowed by zeroes for unused entries. e.g. For a monoclinic
cell a, b, c, beta, 0, 0 will be returned; for a tetragonal cell
a, c, 0, 0, 0, 0 will be returned.
This method converts the contracted set cell of cell parameters
(real or reciprocal) to the full set (see also contractCell(..) method).
- Method Definition:
- public static double[] expandCell(double[] cell, int isys, boolean recip)
- Parameters List:
- cell
- An array of the contracted cell parameters (need only be
of the length required to hold the unique variable parameters)
- isys
- The crystal system number 1-7.
- recip
- Set to true if a reciprocal cell or false if a real cell.
(required to set the correct angle for a hexagonal cell)
- Method Return:
-
An array of the six full cell parameters.
This method returns the number of unique variable cell parameters (see
also contractCell(..) method).
for a given crystal system.
- Method Definition:
- public static int numberUniqueCellParameters(int isys)
- Parameters List:
- isys
- Crystal system 1-7.
- Method Return:
-
The number of unique variable cell parameters.
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