calc_raga_angles

pypulseqpp.calc_raga_angles()

Return rational approximate golden-angle (RAGA) rotations.

The finite support contains fib(approximation_order, tiny_index) equidistant angles. Angles repeat when n exceeds the support size.

Parameters:

• n (int) – Number of angles.

• tiny_index (int, default=1) – Tiny-golden index the rational approximation is built from.

• approximation_order (int, default=13) – Fibonacci order; sets the size of the angular support.

Returns:

Angles (rad), length n, drawn from a finite equidistant support.

Return type:

numpy.ndarray

Raises:

ValueError – If n is below one, or the approximation index is out of range.

Examples

>>> import numpy as np
>>> import pypulseqpp as pp
>>> angles = pp.calc_raga_angles(1000, approximation_order=8)
>>> len(np.unique(angles.round(9)))
21

References

Scholand et al., RAGA sampling, DOI 10.1002/mrm.30254.

See also

calc_golden_angles

the irrational increment RAGA approximates.