diffcalc.hkl.geometry

Module providing diffractometer position definition and rotation matrices.

Diffractometer axes and rotation matrix definitions are following conventions described in [1].

References

[1]

H. You. “Angle calculations for a ‘4S+2D’ six-circle diffractometer” J. Appl. Cryst. (1999). 32, 614-623.

Functions

get_q_phi(pos)	Calculate scattering vector in laboratory frame.
get_rotation_matrices(pos)	Create rotation matrices corresponding to the diffractometer axes.
rot_CHI(chi)	Return rotation matrix corresponding to chi axis.
rot_DELTA(delta)	Return rotation matrix corresponding to delta axis.
rot_ETA(eta)	Return rotation matrix corresponding to eta axis.
rot_MU(mu_or_alpha)	Return rotation matrix corresponding to mu axis.
rot_NU(nu)	Return rotation matrix corresponding to nu axis.
rot_PHI(phi)	Return rotation matrix corresponding to phi axis.

Classes

Position([mu, delta, nu, eta, chi, phi])

Class representing diffractometer orientation.

class diffcalc.hkl.geometry.Position(mu: float = 0.0, delta: float = 0.0, nu: float = 0.0, eta: float = 0.0, chi: float = 0.0, phi: float = 0.0)

Class representing diffractometer orientation.

Diffractometer orientation corresponding to (4+2) geometry defined in H. You paper (add reference)

fields

Tuple with angle names

Type:

Tuple[str, str, str, str, str, str]

mu

mu angle value

Type:

float, default = 0.0

delta

delta angle value

Type:

float, default = 0.0

nu

nu angle value

Type:

float, default = 0.0

eta

eta angle value

Type:

float, default = 0.0

chi

chi angle value

Type:

float, default = 0.0

phi

phi angle value

Type:

float, default = 0.0

Attributes:

asdict

Return dictionary of diffractometer angles.

astuple

Return tuple of diffractometer angles.

chi

Value of of chi angle.

delta

Value of of delta angle.

eta

Value of of eta angle.

mu

Value of of mu angle.

nu

Value of of nu angle.

phi

Value of of phi angle.

fields: Tuple[str, str, str, str, str, str] = ('mu', 'delta', 'nu', 'eta', 'chi', 'phi')

property mu: float

Value of of mu angle.

property delta: float

Value of of delta angle.

property nu: float

Value of of nu angle.

property eta: float

Value of of eta angle.

property chi: float

Value of of chi angle.

property phi: float

Value of of phi angle.

property asdict: Dict[str, float]

Return dictionary of diffractometer angles.

Returns:

Dictionary of axis names and angle values.

Return type:

Dict[str, float]

property astuple: Tuple[float, float, float, float, float, float]

Return tuple of diffractometer angles.

Returns:

Tuple of angle values.

Return type:

Tuple[float, float, float, float, float, float]

diffcalc.hkl.geometry.get_rotation_matrices(pos: Position) → Tuple[ndarray, ndarray, ndarray, ndarray, ndarray, ndarray]

Create rotation matrices corresponding to the diffractometer axes.

Parameters:

pos (Position) – Position object containing set of diffractometer angles

Returns:

np.ndarray, np.ndarray, np.ndarray, np.ndarray] Tuple containing set of rotation matrices corresponding to input diffractometer angle values.

Return type:

Tuple[np.ndarray, np.ndarray,

diffcalc.hkl.geometry.rot_NU(nu: float) → ndarray

Return rotation matrix corresponding to nu axis.

Parameters:

• nu (float) –

• angle (nu axis) –

Returns:

Rotation matrix as a NumPy array.

Return type:

np.ndarray

diffcalc.hkl.geometry.rot_DELTA(delta: float) → ndarray

Return rotation matrix corresponding to delta axis.

Parameters:

• delta (float) –

• angle (delta axis) –

Returns:

Rotation matrix as a NumPy array.

Return type:

np.ndarray

diffcalc.hkl.geometry.rot_MU(mu_or_alpha: float) → ndarray

Return rotation matrix corresponding to mu axis.

Parameters:

• mu (float) –

• angle (mu axis) –

Returns:

Rotation matrix as a NumPy array.

Return type:

np.ndarray

diffcalc.hkl.geometry.rot_ETA(eta: float) → ndarray

Return rotation matrix corresponding to eta axis.

Parameters:

• eta (float) –

• angle (eta axis) –

Returns:

Rotation matrix as a NumPy array.

Return type:

np.ndarray

diffcalc.hkl.geometry.rot_CHI(chi: float) → ndarray

Return rotation matrix corresponding to chi axis.

Parameters:

• chi (float) –

• angle (chi axis) –

Returns:

Rotation matrix as a NumPy array.

Return type:

np.ndarray

diffcalc.hkl.geometry.rot_PHI(phi: float) → ndarray

Return rotation matrix corresponding to phi axis.

Parameters:

• phi (float) –

• angle (phi axis) –

Returns:

Rotation matrix as a NumPy array.

Return type:

np.ndarray

diffcalc.hkl.geometry.get_q_phi(pos: Position) → ndarray

Calculate scattering vector in laboratory frame.

Calculate hkl in the phi frame in units of 2 * pi / lambda.

Parameters:

pos (object) – Diffractometer angles in radians.

Returns:

Scattering vector coordinates corresponding to the input position.

Return type:

matrix