srsRAN_4G/lte/phy/lib/utils/src/dft.c

/**
 *
 * \section COPYRIGHT
 *
 * Copyright 2013-2014 The libLTE Developers. See the
 * COPYRIGHT file at the top-level directory of this distribution.
 *
 * \section LICENSE
 *
 * This file is part of the libLTE library.
 *
 * libLTE is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation, either version 3 of
 * the License, or (at your option) any later version.
 *
 * libLTE is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * A copy of the GNU Lesser General Public License can be found in
 * the LICENSE file in the top-level directory of this distribution
 * and at http://www.gnu.org/licenses/.
 *
 */


#include <math.h>
#include <complex.h>
#include <fftw3.h>
#include <string.h>

#include "liblte/phy/utils/dft.h"

#define div(a,b) ((a-1)/b+1)


int dft_plan_vector(dft_plan_t *plans, const int *dft_points,
                    dft_mode_t *modes, dft_dir_t *dirs, int nof_plans) {
  int i;
  for (i=0;i<nof_plans;i++) {
    if (dft_plan(&plans[i], dft_points[i],modes[i],dirs[i])) {
      return -1;
    }
  }
  return 0;
}

int dft_plan_multi_c2c(dft_plan_t *plans, const int *dft_points,
                       dft_dir_t dir, int nof_plans) {
  int i;
  for (i=0;i<nof_plans;i++) {
    if (dft_plan(&plans[i],dft_points[i],COMPLEX_2_COMPLEX,dir)) {
      return -1;
    }
  }
  return 0;
}

int dft_plan_multi_c2r(dft_plan_t *plans, const int *dft_points,
                       dft_dir_t dir, int nof_plans) {
  int i;
  for (i=0;i<nof_plans;i++) {
    if (dft_plan(&plans[i], dft_points[i],COMPLEX_2_REAL,dir)) {
      return -1;
    }
  }
  return 0;
}

int dft_plan_multi_r2r(dft_plan_t *plans, const int *dft_points,
                       dft_dir_t dir, int nof_plans) {
  int i;
  for (i=0;i<nof_plans;i++) {
    if (dft_plan(&plans[i], dft_points[i],REAL_2_REAL,dir)) {
      return -1;
    }
  }
  return 0;
}


int dft_plan(dft_plan_t *plan, const int dft_points,
             dft_mode_t mode, dft_dir_t dir) {

  switch(mode) {
  case COMPLEX_2_COMPLEX:
    if (dft_plan_c2c(plan,dft_points,dir)) {
      return -1;
    }
    break;
  case REAL_2_REAL:
    if (dft_plan_r2r(plan,dft_points,dir)) {
      return -1;
    }
    break;
  case COMPLEX_2_REAL:
    if (dft_plan_c2r(plan,dft_points,dir)) {
      return -1;
    }
    break;
  }
  return 0;
}

static void allocate(dft_plan_t *plan, int size_in, int size_out, int len) {
  plan->in = fftwf_malloc(size_in*len);
  plan->out = fftwf_malloc(size_out*len);
}

int dft_plan_c2c(dft_plan_t *plan, const int dft_points, dft_dir_t dir) {
  int sign;
  sign = (dir == FORWARD) ? FFTW_FORWARD : FFTW_BACKWARD;
  allocate(plan,sizeof(fftwf_complex),sizeof(fftwf_complex), dft_points);

  plan->p = fftwf_plan_dft_1d(dft_points, plan->in, plan->out, sign, 0U);
  if (!plan->p) {
    return -1;
  }

  plan->size = dft_points;
  plan->mode = COMPLEX_2_COMPLEX;

  return 0;
}

int dft_plan_r2r(dft_plan_t *plan, const int dft_points, dft_dir_t dir) {
  int sign;
  sign = (dir == FORWARD) ? FFTW_R2HC : FFTW_HC2R;

  allocate(plan,sizeof(float),sizeof(float), dft_points);

  plan->p = fftwf_plan_r2r_1d(dft_points, plan->in, plan->out, sign, 0U);
  if (!plan->p) {
    return -1;
  }

  plan->size = dft_points;
  plan->mode = REAL_2_REAL;

  return 0;
}

int dft_plan_c2r(dft_plan_t *plan, const int dft_points, dft_dir_t dir) {
  if (dft_plan_c2c(plan, dft_points, dir)) {
    return -1;
  }
  plan->mode = COMPLEX_2_REAL;
  return 0;
}

static void copy(char *dst, char *src, int size_d, int len, int mirror, int dc_offset) {
  int offset=dc_offset?1:0;
  int hlen;
  if (mirror == DFT_MIRROR_PRE) {
    hlen = div(len,2);
    memset(dst,0,size_d*offset);
    memcpy(&dst[offset*size_d], &src[size_d*hlen], size_d*(hlen-offset));
    memcpy(&dst[hlen*size_d], src, size_d*(len - hlen));
  } else if (mirror == DFT_MIRROR_POS) {
    hlen = div(len,2);
    memcpy(dst, &src[size_d*hlen], size_d*hlen);
    memcpy(&dst[hlen*size_d], &src[size_d*offset], size_d*(len - hlen));
  } else {
    memcpy(dst,src,size_d*len);
  }
}

void dft_run(dft_plan_t *plan, void *in, void *out) {
  switch(plan->mode) {
  case COMPLEX_2_COMPLEX:
    dft_run_c2c(plan,in,out);
    break;
  case REAL_2_REAL:
    dft_run_r2r(plan,in,out);
    break;
  case COMPLEX_2_REAL:
    dft_run_c2r(plan,in,out);
    break;
  }
}

void dft_run_c2c(dft_plan_t *plan, dft_c_t *in, dft_c_t *out) {
  float norm;
  int i;
  fftwf_complex *f_out = plan->out;

  copy((char*) plan->in,(char*) in,sizeof(dft_c_t),plan->size,plan->options & DFT_MIRROR_PRE,
      plan->options & DFT_DC_OFFSET);

  fftwf_execute(plan->p);

  if (plan->options & DFT_NORMALIZE) {
    /**FIXME: Use VOLK */
    norm = sqrtf(plan->size);
    for (i=0;i<plan->size;i++) {
      f_out[i] /= norm;
    }
  }
  if (plan->options & DFT_OUT_DB) {
    for (i=0;i<plan->size;i++) {
      f_out[i] = 10*log10(f_out[i]);
    }
  }
  copy((char*) out,(char*) plan->out,sizeof(dft_c_t),plan->size,plan->options & DFT_MIRROR_POS,
      plan->options & DFT_DC_OFFSET);
}

void dft_run_r2r(dft_plan_t *plan, dft_r_t *in, dft_r_t *out) {
  float norm;
  int i;
  int len = plan->size;
  float *f_out = plan->out;

  copy((char*) plan->in,(char*) in,sizeof(dft_r_t),plan->size,plan->options & DFT_MIRROR_PRE,
      plan->options & DFT_DC_OFFSET);

  fftwf_execute(plan->p);

  if (plan->options & DFT_NORMALIZE) {
    norm = plan->size;
    for (i=0;i<len;i++) {
      f_out[i] /= norm;
    }
  }
  if (plan->options & DFT_PSD) {
    for (i=0;i<(len+1)/2-1;i++) {
      out[i] = sqrtf(f_out[i]*f_out[i]+f_out[len-i-1]*f_out[len-i-1]);
    }
  }
  if (plan->options & DFT_OUT_DB) {
    for (i=0;i<len;i++) {
      out[i] = 10*log10(out[i]);
    }
  }
}

void dft_run_c2r(dft_plan_t *plan, dft_c_t *in, dft_r_t *out) {
  int i;
  float norm;
  float *f_out = plan->out;

  copy((char*) plan->in,(char*) in,sizeof(dft_r_t),plan->size,plan->options & DFT_MIRROR_PRE,
      plan->options & DFT_DC_OFFSET);

  fftwf_execute(plan->p);

  if (plan->options & DFT_NORMALIZE) {
    norm = plan->size;
    for (i=0;i<plan->size;i++) {
      f_out[i] /= norm;
    }
  }
  if (plan->options & DFT_PSD) {
    for (i=0;i<plan->size;i++) {
      out[i] = (__real__ f_out[i])*(__real__ f_out[i])+
           (__imag__ f_out[i])*(__imag__ f_out[i]);
      if (!(plan->options & DFT_OUT_DB)) {
        out[i] = sqrtf(out[i]);
      }
    }
  }
  if (plan->options & DFT_OUT_DB) {
    for (i=0;i<plan->size;i++) {
      out[i] = 10*log10(out[i]);
    }
  }
}


void dft_plan_free(dft_plan_t *plan) {
  if (!plan) return;
  if (!plan->size) return;
  if (plan->in) fftwf_free(plan->in);
  if (plan->out) fftwf_free(plan->out);
  if (plan->p) fftwf_destroy_plan(plan->p);
  bzero(plan, sizeof(dft_plan_t));
}

void dft_plan_free_vector(dft_plan_t *plan, int nof_plans) {
  int i;
  for (i=0;i<nof_plans;i++) {
    dft_plan_free(&plan[i]);
  }
}