// file: $SPEECH_HOMEWORK4/hw4/class/snr_ratio/v1.0/snr_lp_0.cc
//

// isip include files
//
#include <string.h>
#include <math.h>
#include "signal_noise_ratio.h"
#include "signal_noise_ratio_constants.h"
#include <integral.h>
#include <integral_constants.h>

// method: perform_lp_cc
//
// arguments:
//  float_4* buffer (input/output) signal to perform hamming window on
//  int_4 samples_per_window (input) the number of samples in one window
//
// return: a logical_1 indicating status
//
logical_1 Signal::perform_lp_cc(float_4* buffer_a, float_4**& lp_values_a,
				 int_4 samples_per_window_a) {

  // define gain variable and lp predictor coefficients
  //
  float_4* lp_gain = new float_4[lp_order_d + 1];
  float_4** auto_corr_values = new float_4*[num_chans_d];
  float_4** lp_pred = new float_4*[num_chans_d];
  for (int_4 i=0; i<num_chans_d; i++) {
    auto_corr_values[i] = new float_4[lp_order_d + 1];
    memset(auto_corr_values[i], 0, sizeof(float_4) * (lp_order_d + 1));
    lp_pred[i] = new float_4[lp_order_d + 1];
    memset(lp_pred[i], 0, sizeof(float_4) * (lp_order_d + 1));
  }
  for (int_4 i=0; i<=lp_order_d; i++) {
    lp_gain[i] = 1;
  }

  // compute the auto correlation
  //
  perform_autocorrelation_cc(buffer_a, auto_corr_values, samples_per_window_a);

  // calculate the lp predictor coefficients
  //
  calculate_lp_pred_cc(lp_pred, auto_corr_values, lp_gain);

  // calculate the spectrum
  //
  calculate_lp_spectrum_cc(lp_pred, lp_values_a,
			   samples_per_window_a, lp_gain);
  
  for (int_4 i=0; i<num_chans_d; i++) {
    delete [] auto_corr_values[i];
    delete [] lp_pred[i];
  }
  delete [] auto_corr_values;
  delete [] lp_pred;
  delete [] lp_gain;
  
  // exit gracefully
  //
  return ISIP_TRUE;
  
}