Module: engine

Low-level support to Hkl computation engine support for diffractometers

CalcParameter(param, geometry, *args, **kwargs)	Like calc parameter but needs reference to a geometry object.
Engine(calc, engine, engine_list)	HKL calculation engine
Parameter(param[, units, name, inverted])	HKL library parameter object
Solution(engine, list_item, class_)	Solution of the conversion from (hkl) to axes.

class hkl.engine.CalcParameter(param, geometry, *args, **kwargs)

Like calc parameter but needs reference to a geometry object. Updates to the parameter should be propagated back to the geometry.

fit	True if the parameter can be fit or not
limits	Allowed range of values (low, high).
value	Position of this axis.

Parameters:

• param (HklParameter)

• geometry (Geometry object)

property fit

True if the parameter can be fit or not

property limits

Allowed range of values (low, high).

property value

Position of this axis.

class hkl.engine.Engine(calc, engine, engine_list)

HKL calculation engine

engine	The calculation engine
mode	HKL calculation mode (see also HklCalc.modes)
name	Name of this engine.
parameters	List the names of the additional parameters.
parameters_values	List the values of the additional parameters.
pseudo_axes	[(name, value)].
pseudo_axis_names	List the names of the pseudo axes.
pseudo_positions	List the values of the pseudo positioners.
solutions	Allowed real solutions given the pseudo position.
units	The units used for calculations
update()	Calculate the pseudo axis positions from the real axis positions.

property _units

The (internal) units used for calculations

property axes_c

HKL real axis names (held constant during forward() computation).

property axes_r

HKL real axis names (read-only).

property axes_w

HKL real axis names (written by forward() computation).

property engine

The calculation engine

property mode

HKL calculation mode (see also HklCalc.modes)

property name

Name of this engine.

property parameters

List the names of the additional parameters.

property parameters_values

List the values of the additional parameters.

property pseudo_axes

[(name, value)].

Type:

List of pseudo axes as tuples

property pseudo_axis_names

List the names of the pseudo axes.

property pseudo_positions

List the values of the pseudo positioners.

property solutions

Allowed real solutions given the pseudo position.

property units

The units used for calculations

update()

Calculate the pseudo axis positions from the real axis positions.

class hkl.engine.Parameter(param, units='user', name=None, inverted=False)

HKL library parameter object

inverted	Is the value inverted internally?
hkl_parameter	The HKL library parameter object
units	Either user or default.
name	Name of this parameter.
value	Value used (in forward() method) if held constant by the mode.
user_units	A string representing the user unit type
default_units	A string representing the default unit type
limits	(low, high)

Example:

Parameter(
        name='None (internally: ux)',
        limits=(min=-180.0, max=180.0),
        value=0.0,
        fit=True,
        inverted=False,
        units='Degree')

property default_units

A string representing the default unit type

property fit

True if the parameter can be fit or not

property hkl_parameter

The HKL library parameter object

property inverted

Is the value inverted internally?

property limits

(low, high)

property name

Name of this parameter.

property units

Either user or default.

property user_units

A string representing the user unit type

property value

Value used (in forward() method) if held constant by the mode.

class hkl.engine.Solution(engine, list_item, class_)

Solution of the conversion from (hkl) to axes.

axis_names	List real axis names of the solution.
positions	List real axis values of the solution.
select()	Select a solution.
units

property axis_names

List real axis names of the solution.

property positions

List real axis values of the solution.

select()

Select a solution.