#ifndef ALCOMPLEX_H
#define ALCOMPLEX_H

#include <complex>

#include "alspan.h"

/**
 * Iterative implementation of 2-radix FFT (In-place algorithm). Sign = -1 is
 * FFT and 1 is iFFT (inverse). Fills the buffer with the Discrete Fourier
 * Transform (DFT) of the time domain data stored in the buffer. The buffer is
 * an array of complex numbers, and MUST BE power of two.
 */
void complex_fft(const al::span<std::complex<double>> buffer, const double sign);

/**
 * Calculate the complex helical sequence (discrete-time analytical signal) of
 * the given input using the discrete Hilbert transform (In-place algorithm).
 * Fills the buffer with the discrete-time analytical signal stored in the
 * buffer. The buffer is an array of complex numbers and MUST BE power of two,
 * and the imaginary components should be cleared to 0.
 */
void complex_hilbert(const al::span<std::complex<double>> buffer);

#endif /* ALCOMPLEX_H */

#ifndef ALCOMPLEX_H
#define ALCOMPLEX_H

#include <complex>

#include "alspan.h"

/**
 * Iterative implementation of 2-radix FFT (In-place algorithm). Sign = -1 is
 * FFT and 1 is iFFT (inverse). Fills the buffer with the Discrete Fourier
 * Transform (DFT) of the time domain data stored in the buffer. The buffer is
 * an array of complex numbers, and MUST BE power of two.
 */
void complex_fft(const al::span<std::complex<double>> buffer, const double sign);

/**
 * Calculate the complex helical sequence (discrete-time analytical signal) of
 * the given input using the discrete Hilbert transform (In-place algorithm).
 * Fills the buffer with the discrete-time analytical signal stored in the
 * buffer. The buffer is an array of complex numbers and MUST BE power of two.
 */
void complex_hilbert(const al::span<std::complex<double>> buffer);

#endif /* ALCOMPLEX_H */

--- 
+++ 
@@ -17,7 +17,8 @@
  * Calculate the complex helical sequence (discrete-time analytical signal) of
  * the given input using the discrete Hilbert transform (In-place algorithm).
  * Fills the buffer with the discrete-time analytical signal stored in the
- * buffer. The buffer is an array of complex numbers and MUST BE power of two.
+ * buffer. The buffer is an array of complex numbers and MUST BE power of two,
+ * and the imaginary components should be cleared to 0.
  */
 void complex_hilbert(const al::span<std::complex<double>> buffer);
 
Add a note about clearing complex_hilbert's imaginary input
