Function from_complex 

fn from_complex(real: &[f64], imag: &[f64]) -> (Vec<f64>, Vec<f64>)

Magnitude and phase of interpolated real and imaginary parts, the same on every target (see the module docs). Phase is 0 where both parts are zero: there is no signal there, and atan2 would otherwise return 0 or ±π depending on the signs of the zeros.