// file: $ECE_8993/util/calculate_lpc/v1.0/clpc_comp_3.cc
//
// computes the linear prediction spectrum coefficients of the input data
//

// isip include files
//
#include <integral.h>
#include <integral_constants.h>

// local include files
//
#include "calculate_lpc.h"

#include "calculate_lpc_constants.h"

// function: compute_lp_cc
//
// arguments:
//
//  float_4* data: (input) a single channel of sampled data
//  float_4* lp_spectrum_coeffs: (output) magnitude of the lp coefficients
//  int_4 num_samples: (input) number of samples in the data stream
//  int_4 lp_order: (input) order of the lp model
//  
// return value: a logical_1 indicating status
//
// this function computes the lp spectrum coefficients of the input data and
// stores the magnitude spectrum coefficients in the output array array
//
logical_1 compute_lp_cc(float_4* data_a, float_4* lp_spectrum_coeffs_a,
			 int_4 num_samples_a, int_4 lp_order_a) {

  // allocate memory for the autocorrelation terms
  //
  float_4* autocor_coeffs = new float_4[lp_order_a + 1];
  
  // calculate the autocorrelation terms for the lp analysis
  //
  compute_autocorrelation_cc(data_a, autocor_coeffs, num_samples_a,
			     lp_order_a);
  
  // debugging output
  //
  for (int_4 i = 0; i < lp_order_a+1; i++) {
    fprintf(stdout, "AUTOCORRELATION COEFFS: index = %ld   value = %.6f\n",
	    i, autocor_coeffs[i]);
  }

  // setup variables for the predictor coefficients and the gain
  //
  float_4 lp_gain = (float_4)1.0;
  float_4* lp_predictor_coeffs = new float_4[lp_order_a + 1];

  // compute the lp predictor coefficients
  //
  compute_lp_coeffs_cc(lp_predictor_coeffs, lp_order_a, autocor_coeffs,
		       lp_gain);

  // debugging output
  //
  for (int_4 i = 0; i < lp_order_a+1; i++) {
    fprintf(stdout, "LP PREDICTOR COEFFS: index = %ld   value = %.6f\n",
	    i, lp_predictor_coeffs[i]);
  }

  // debugging output
  //
  fprintf(stdout, "LP_GAIN: %.6f\n", lp_gain);
  
  // compute the spectrum of the lp signal
  //
  compute_lp_spect_cc(lp_predictor_coeffs, lp_spectrum_coeffs_a, lp_order_a,
		      num_samples_a, lp_gain);

  // delete memory and clean up
  //
  delete [] autocor_coeffs;
  delete [] lp_predictor_coeffs;  
  
  // exit gracefully
  //
  return ISIP_TRUE;
}