/// <summary>
/// calculate PSD
/// </summary>
/// <param name="data">data for PSD</param>
/// <param name="start_pos">start pos</param>
/// <param name="end_pos">end pos, end_pos - start_pos must be a power of 2</param>
/// <param name="sampling_rate">sampling rate</param>
/// <param name="window">window function</param>
/// <returns>Tuple of ampls and freqs arrays of size N / 2 + 1</returns>
public static Tuple <double[], double[]> get_psd(double[] data, int start_pos, int end_pos, int sampling_rate, int window)
{
if ((start_pos < 0) || (end_pos > data.Length) || (start_pos >= end_pos))
{
throw new BrainFlowException((int)CustomExitCodes.INVALID_ARGUMENTS_ERROR);
}
int len = end_pos - start_pos;
if ((len & (len - 1)) != 0)
{
throw new BrainFlowException((int)CustomExitCodes.INVALID_ARGUMENTS_ERROR);
}
double[] data_to_process = new double[len];
Array.Copy(data, start_pos, data_to_process, 0, len);
double[] temp_ampls = new double[len / 2 + 1];
double[] temp_freqs = new double[len / 2 + 1];
int res = DataHandlerLibrary.get_psd(data_to_process, len, sampling_rate, window, temp_ampls, temp_freqs);
if (res != (int)CustomExitCodes.STATUS_OK)
{
throw new BrainFlowException(res);
}
Tuple <double[], double[]> return_data = new Tuple <double[], double[]>(temp_ampls, temp_freqs);
return(return_data);
}