TransformChain¶
- class menpo.transform.base.composable.TransformChain(transforms)[source]¶
Bases: ComposableTransform
A chain of transforms that can be efficiently applied one after the other.
This class is the natural product of composition. Note that objects may know how to compose themselves more efficiently - such objects implement the ComposableTransform or VComposable interfaces.
Parameters: transforms : list of Transform
The list of transforms to be applied. Note that the first transform will be applied first - the result of which is fed into the second transform and so on until the chain is exhausted.
- apply(x, **kwargs)¶
Applies this transform to x.
If x is Transformable, x will be handed this transform object to transform itself non-destructively (a transformed copy of the object will be returned).
If not, x is assumed to be an ndarray. The transformation will be non-destructive, returning the transformed version.
Any kwargs will be passed to the specific transform _apply() method.
Parameters: x : Transformable or (n_points, n_dims) ndarray
The array or object to be transformed.
kwargs : dict
Passed through to _apply().
Returns: transformed : type(x)
The transformed object or array
- apply_inplace(x, **kwargs)¶
Applies this transform to a Transformable x destructively.
Any kwargs will be passed to the specific transform _apply() method.
Parameters: x : Transformable
The Transformable object to be transformed.
kwargs : dict
Passed through to _apply().
Returns: transformed : type(x)
The transformed object
- compose_after(transform)¶
A Transform that represents this transform composed after the given transform:
c = a.compose_after(b) c.apply(p) == a.apply(b.apply(p))
a and b are left unchanged.
This corresponds to the usual mathematical formalism for the compose operator, o.
An attempt is made to perform native composition, but will fall back to a TransformChain as a last resort. See composes_with for a description of how the mode of composition is decided.
Parameters: transform : Transform
Transform to be applied before self
Returns: transform : Transform or TransformChain
If the composition was native, a single new Transform will be returned. If not, a TransformChain is returned instead.
- compose_after_inplace(transform)¶
Update self so that it represents this transform composed after the given transform:
a_orig = deepcopy(a) a.compose_after_inplace(b) a.apply(p) == a_orig.apply(b.apply(p))
a is permanently altered to be the result of the composition. b is left unchanged.
Parameters: transform : composes_inplace_with
Transform to be applied before self
Raises: ValueError :
If transform isn’t an instance of composes_inplace_with
- compose_before(transform)¶
A Transform that represents this transform composed before the given transform:
c = a.compose_before(b) c.apply(p) == b.apply(a.apply(p))
a and b are left unchanged.
An attempt is made to perform native composition, but will fall back to a TransformChain as a last resort. See composes_with for a description of how the mode of composition is decided.
Parameters: transform : Transform
Transform to be applied after self
Returns: transform : Transform or TransformChain
If the composition was native, a single new Transform will be returned. If not, a TransformChain is returned instead.
- compose_before_inplace(transform)¶
Update self so that it represents this transform composed before the given transform:
a_orig = deepcopy(a) a.compose_before_inplace(b) a.apply(p) == b.apply(a_orig.apply(p))
a is permanently altered to be the result of the composition. b is left unchanged.
Parameters: transform : composes_inplace_with
Transform to be applied after self
Raises: ValueError :
If transform isn’t an instance of composes_inplace_with
- composes_inplace_with[source]¶
The Transform s that this transform composes inplace with natively (i.e. no TransformChain will be produced).
An attempt to compose inplace against any type that is not an instance of this property on this class will result in an Exception.
Type: Transform or tuple of Transform s
- composes_with¶
The Transform s that this transform composes with natively (i.e. no TransformChain will be produced).
If native composition is not possible, falls back to producing a TransformChain.
By default, this is the same list as composes_inplace_with.
Type: Transform or tuple of Transform s
- n_dims¶
The dimensionality of the data the transform operates on.
None if the transform is not dimension specific.
Type: int or None
- n_dims_output¶
The output of the data from the transform.
None if the output of the transform is not dimension specific.
Type: int or None