Class SymmetryConstraints
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Generate symmetry constraints for specified positions
Data members:
spacegroup -- instance of SpaceGroup
positions -- all positions to be constrained
Uijs -- thermal factors for all positions (defaults to zeros)
sgoffset -- optional offset of space group origin [0, 0, 0]
eps -- cutoff for equivalent positions
Calculated data members:
corepos -- list of of positions in the asymmetric unit
coremap -- dictionary mapping indices of asymmetric core positions
to indices of all symmetry related positions
poseqns -- list of coordinate formula dictionaries per each site.
Formula dictionary keys are from ("x", "y", "z") and
the values are formatted as [[-]{x|y|z}%i] [{+|-}%g],
for example: "x0", "-x3", "z7 +0.5", "0.25".
pospars -- list of (xyz symbol, value) pairs
Ueqns -- list of anisotropic atomic displacement formula
dictionaries per each position. Formula dictionary
keys are from ('U11','U22','U33','U12','U13','U23')
and the values are formatted as {[%g*][Uij%i]|0},
for example: "U110", "0.5*U2213", "0"
Upars -- list of (U symbol, value) pairs
Uisotropy -- list of bool flags for isotropic thermal displacements
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__init__(self,
spacegroup,
positions,
Uijs=None,
sgoffset=[0, 0, 0],
eps=1e-05)
Initialize and calculate SymmetryConstraints. |
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posparSymbols(self)
Return list of standard position parameter symbols. |
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posparValues(self)
Return list of position parameters values. |
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UparSymbols(self)
Return list of standard atom displacement parameter symbols. |
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UparValues(self)
Return list of atom displacement parameters values. |
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UFormulas(self,
Usymbols=None)
List of atom displacement formulas with custom parameter symbols. |
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__init__(self,
spacegroup,
positions,
Uijs=None,
sgoffset=[0, 0, 0],
eps=1e-05)
(Constructor)
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Initialize and calculate SymmetryConstraints.
spacegroup -- instance of SpaceGroup
positions -- list of all positions to be constrained
Uijs -- list of U matrices for all constrained positions
sgoffset -- optional offset of space group origin [0, 0, 0]
eps -- cutoff for equivalent positions
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Find constraints for positions and anisotropic displacements Uij
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List of position formulas with custom parameter symbols.
xyzsymbols -- list of custom symbols used in formula strings
Return list of coordinate formulas dictionaries. Formulas dictionary
keys are from ("x", "y", "z") and the values are formatted as
[[-]{symbol}] [{+|-}%g], for example: "x0", "-sym", "@7 +0.5", "0.25".
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positionFormulasPruned(self,
xyzsymbols=None)
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List of position formula dictionaries with constant items removed.
See also positionFormulas().
xyzsymbols -- list of custom symbols used in formula strings
Return list of coordinate formula dictionaries.
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List of atom displacement formulas with custom parameter symbols.
Usymbols -- list of custom symbols used in formula strings
Return list of atom displacement formula dictionaries per each site.
Formula dictionary keys are from ('U11','U22','U33','U12','U13','U23')
and the values are formatted as {[%g*][Usymbol]|0}, for example:
"U11", "0.5*@37", "0".
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List of atom displacement formula dictionaries with constant items
removed. See also UFormulas().
Usymbols -- list of custom symbols used in formula strings
Return list of atom displacement formulas in tuples of
(U11, U22, U33, U12, U13, U23).
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