quantax.nn.cardioid

quantax.nn.cardioid(x: Array) → Array

\(f(z) = \frac{1}{2}(1 + \cos\phi)\,z\), where \(\phi = \arg z\).

P. Virtue, S. X. Yu and M. Lustig, “Better than real: Complex-valued neural nets for MRI fingerprinting,” 2017 IEEE International Conference on Image Processing (ICIP), Beijing, China, 2017, pp. 3953-3957, doi: 10.1109/ICIP.2017.8297024.