/* filter/test_rmedian.c

 * 

 * Copyright (C) 2018 Patrick Alken

 * 

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 3 of the License, or (at

 * your option) any later version.

 * 

 * This program 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

 * General Public License for more details.

 * 

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.

 */

#include <gsl/gsl_math.h>

#include <gsl/gsl_vector.h>

#include <gsl/gsl_test.h>

#include <gsl/gsl_rng.h>

#include <gsl/gsl_randist.h>

#include <gsl/gsl_statistics.h>

/* slow/dumb rmedian which constructs actual window for each sample, sorts

 * it and finds median */

static int

slow_rmedian(const gsl_filter_end_t endtype, const gsl_vector * x, gsl_vector * y, const int K)

{

  const int n = (int) x->size;

  const int H = K / 2;

  double *window = malloc(K * sizeof(double));

  int i;

  for (i = 0; i < n; ++i)

    {

      size_t wsize = gsl_movstat_fill(endtype, x, i, H, H, window);

      double yi;

      int j;

      /* fill first half of window with previous filter output values */

      for (j = i - H; j < i; ++j)

        {

          if (j < 0)

            {

              if (endtype == GSL_FILTER_END_PADVALUE)

                window[j - i + H] = gsl_vector_get(x, 0);

              else if (endtype == GSL_FILTER_END_PADZERO)

                window[j - i + H] = 0.0;

            }

          else

            {

              window[j - i + H] = gsl_vector_get(y, j);

            }

        }

      yi = gsl_stats_median(window, 1, wsize);

      gsl_vector_set(y, i, yi);

    }

  free(window);

  return GSL_SUCCESS;

}

/* test square wave input (root signal) */

static void

test_rmedian_root(const gsl_filter_end_t etype, const size_t n, const size_t k)

{

  const double tol = 1.0e-12;

  gsl_filter_rmedian_workspace *w = gsl_filter_rmedian_alloc(k);

  gsl_vector *x = gsl_vector_alloc(n);

  gsl_vector *y = gsl_vector_alloc(n);

  char buf[2048];

  size_t i;

  /* test a root sequence (square input): x = [zero one zero] */

  gsl_vector_set_all(x, 0.0);

  for (i = n / 3; i <= n / 2; ++i)

    gsl_vector_set(x, i, 1.0);

  /* compute y = rmedian(x) and test y = x */

  gsl_filter_rmedian(etype, x, y, w);

  sprintf(buf, "n=%zu k=%zu RMF square wave root sequence", n, k);

  compare_vectors(tol, y, x, buf);

  gsl_vector_free(x);

  gsl_vector_free(y);

  gsl_filter_rmedian_free(w);

}

/* test random input and in-place */

static void

test_rmedian_random(const gsl_filter_end_t etype, const size_t n, const int K, gsl_rng * r)

{

  const double tol = 1.0e-12;

  gsl_filter_rmedian_workspace *w = gsl_filter_rmedian_alloc(K);

  gsl_vector *x = gsl_vector_alloc(n);

  gsl_vector *y = gsl_vector_alloc(n);

  gsl_vector *z = gsl_vector_alloc(n);

  char buf[2048];

  /* test filter with random input against slow algorithm */

  random_vector(x, r);

  /* y = rmedian(x) */

  gsl_filter_rmedian(etype, x, y, w);

  /* y = rmedian(x) with slow algorithm */

  slow_rmedian(etype, x, z, K);

  /* test y = z */

  sprintf(buf, "n=%zu K=%d RMF symmetric random slow test", n, K);

  compare_vectors(tol, y, z, buf);

  /* test in-place filter */

  /* z = rmedian(x) in-place */

  gsl_vector_memcpy(z, x);

  gsl_filter_rmedian(etype, z, z, w);

  sprintf(buf, "n=%zu K=%d RMF symmetric random in-place", n, K);

  compare_vectors(tol, z, y, buf);

  gsl_vector_free(x);

  gsl_vector_free(y);

  gsl_vector_free(z);

  gsl_filter_rmedian_free(w);

}

void

test_rmedian(gsl_rng * rng_p)

{

  /* test root sequences */

  test_rmedian_root(GSL_FILTER_END_PADZERO, 1000, 3);

  test_rmedian_root(GSL_FILTER_END_PADZERO, 2000, 101);

  test_rmedian_root(GSL_FILTER_END_PADVALUE, 1000, 3);

  test_rmedian_root(GSL_FILTER_END_PADVALUE, 2000, 101);

  /* test random input */

  test_rmedian_random(GSL_FILTER_END_PADZERO, 10, 1, rng_p);

  test_rmedian_random(GSL_FILTER_END_PADZERO, 100, 3, rng_p);

  test_rmedian_random(GSL_FILTER_END_PADZERO, 1000, 3, rng_p);

  test_rmedian_random(GSL_FILTER_END_PADZERO, 100, 1001, rng_p);

  test_rmedian_random(GSL_FILTER_END_PADZERO, 5, 7, rng_p);

  test_rmedian_random(GSL_FILTER_END_PADVALUE, 10, 1, rng_p);

  test_rmedian_random(GSL_FILTER_END_PADVALUE, 100, 3, rng_p);

  test_rmedian_random(GSL_FILTER_END_PADVALUE, 1000, 3, rng_p);

  test_rmedian_random(GSL_FILTER_END_PADVALUE, 100, 1001, rng_p);

  test_rmedian_random(GSL_FILTER_END_PADVALUE, 5, 7, rng_p);

}