Parallel2dGeometry.frommatrix¶

classmethod Parallel2dGeometry.frommatrix(apart, dpart, init_matrix, **kwargs)[source]¶

Create an instance of Parallel2dGeometry using a matrix.

This alternative constructor uses a matrix to rotate and translate the default configuration. It is most useful when the transformation to be applied is already given as a matrix.

Parameters:

apart1-dim. RectPartition: Partition of the angle interval.
dpart1-dim. RectPartition: Partition of the detector parameter interval.
init_matrixarray_like, shape (2, 2) or (2, 3), optional: Transformation matrix whose left (2, 2) block is multiplied with the default det_pos_init and det_axis_init to determine the new vectors. If present, the third column acts as a translation after the initial transformation. The resulting det_axis_init will be normalized.
kwargs: Further keyword arguments passed to the class constructor.

Returns:

geometryParallel2dGeometry

Examples

Mirror the second unit vector, creating a left-handed system:

>>> apart = odl.uniform_partition(0, np.pi, 10)
>>> dpart = odl.uniform_partition(-1, 1, 20)
>>> matrix = np.array([[1, 0],
...                    [0, -1]])
>>> geom = Parallel2dGeometry.frommatrix(apart, dpart, matrix)
>>> e_x, e_y = np.eye(2)  # standard unit vectors
>>> np.allclose(geom.det_pos_init, -e_y)
True
>>> np.allclose(geom.det_axis_init, e_x)
True
>>> np.allclose(geom.translation, (0, 0))
True

Adding a translation with a third matrix column:

>>> matrix = np.array([[1, 0, 1],
...                    [0, -1, 1]])
>>> geom = Parallel2dGeometry.frommatrix(apart, dpart, matrix)
>>> np.allclose(geom.translation, (1, 1))
True
>>> np.allclose(geom.det_pos_init, -e_y + (1, 1))
True