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pynbody.transformation.Transformation

pynbody.transformation.Transformation#

class pynbody.transformation.Transformation(f, defer=False, description=None)[source]#

Bases: Transformable

The base class for all transformations.

Note that this class inherits from Transformable, so all transformations are themselves transformable. This means that you can chain transformations together, e.g. for a SimSnap object f:

>>> with f.translate(fshift).rotate_x(45):
>>>    ...
Attributes:
sim

The simulation to which this transformation applies

Methods

apply([force])

Apply the transformation to the simulation it is associated with.

apply_inverse_to(f)

Apply the inverse of this transformation to a specified simulation.

apply_to(f)

Apply this transformation to a specified simulation.

offset_velocity(offset)

Shift the velocity by the given offset.

revert()

Revert the transformation.

rotate(matrix[, description])

Rotates using a specified matrix.

rotate_x(angle)

Rotates about the current x-axis by 'angle' degrees.

rotate_y(angle)

Rotates about the current y-axis by 'angle' degrees.

rotate_z(angle)

Rotates about the current z-axis by 'angle' degrees.

transform(matrix)

Deprecated alias for rotate().

translate(offset)

Translate by the given offset.
__init__(f, defer=False, description=None)[source]#

Initialise a transformation, and apply it if not explicitly deferred

Parameters:

  • f (SimSnap or Transformation) – The simulation or transformation to act on. If a transformation is given, this transformation will be chained to it, i.e. the result will represent the composed transformation.

  • defer (bool) – If True, the transformation is not applied immediately. Otherwise, as soon as the object is constructed the transformation is applied to the simulation

  • description (str) – A description of the transformation to be returned from str() and repr()

apply(force=True)[source]#

Apply the transformation to the simulation it is associated with.

This is either the simulation passed to the constructor or the one passed to the last transformation in the chain. If the transformation has already been applied, a RuntimeError is raised unless force is True, in which case the transformation is applied again.

Parameters:

force (bool) – If True, the transformation is applied even if it has already been applied. Otherwise, a RuntimeError is raised if the transformation has already been applied.

Returns:

The simulation after the transformation has been applied

Return type:

SimSnap

apply_inverse_to(f)[source]#

Apply the inverse of this transformation to a specified simulation.

Chained transformations are applied recursively.

Parameters:

f (SimSnap) – The simulation to apply the transformation to

Returns:

The input simulation (not a copy)

Return type:

SimSnap

apply_to(f: snapshot.SimSnap) → snapshot.SimSnap[source]#

Apply this transformation to a specified simulation.

Chained transformations are applied recursively.

Parameters:

f (SimSnap) – The simulation to apply the transformation to. Any simulation reference stored within the transformation itself is ignored

Returns:

The input simulation (not a copy)

Return type:

SimSnap

offset_velocity(offset)#

Shift the velocity by the given offset.

Returns a pynbody.transformation.GenericTranslation object which can be used as a context manager to ensure that the translation is undone.

For more information, see the pynbody.transformation documentation.

revert()[source]#

Revert the transformation. If it has not been applied, a RuntimeError is raised.

rotate(matrix, description=None)#

Rotates using a specified matrix.

Returns a pynbody.transformation.GenericTranslation object which can be used as a context manager to ensure that the translation is undone.

For more information, see the pynbody.transformation documentation.

Parameters:

  • matrix (array_like) – The 3x3 orthogonal matrix to rotate by

  • description (str) – A description of the rotation to be returned from str() and repr()

rotate_x(angle)#

Rotates about the current x-axis by ‘angle’ degrees.

Returns a pynbody.transformation.GenericTranslation object which can be used as a context manager to ensure that the translation is undone.

For more information, see the pynbody.transformation documentation.

rotate_y(angle)#

Rotates about the current y-axis by ‘angle’ degrees.

Returns a pynbody.transformation.GenericTranslation object which can be used as a context manager to ensure that the translation is undone.

For more information, see the pynbody.transformation documentation.

rotate_z(angle)#

Rotates about the current z-axis by ‘angle’ degrees.

Returns a pynbody.transformation.GenericTranslation object which can be used as a context manager to ensure that the translation is undone.

For more information, see the pynbody.transformation documentation.

property sim: snapshot.SimSnap | None#

The simulation to which this transformation applies

transform(matrix)#

Deprecated alias for rotate().

translate(offset)#

Translate by the given offset.

Returns a pynbody.transformation.GenericTranslation object which can be used as a context manager to ensure that the translation is undone.

For more information, see the pynbody.transformation documentation.

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