/* movstat/apply.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 <config.h>

#include <stdlib.h>

#include <math.h>

#include <gsl/gsl_math.h>

#include <gsl/gsl_errno.h>

#include <gsl/gsl_vector.h>

#include <gsl/gsl_movstat.h>

/*

gsl_movstat_apply_accum()

  Apply moving window statistic to input vector. This is a generalized

routine to handle window endpoints and apply a given accumulator to

the input vector.

Inputs: endtype      - end point handling criteria

        x            - input vector, size n

        accum        - accumulator to apply moving window statistic

        accum_params - parameters to pass to accumulator

        y            - output vector, size n

        z            - second output vector (i.e. minmax), size n; can be NULL

        w            - workspace

Notes:

1) It is allowed to have x = y for in-place moving statistics

*/

int

gsl_movstat_apply_accum(const gsl_movstat_end_t endtype,

                        const gsl_vector * x,

                        const gsl_movstat_accum * accum,

                        void * accum_params,

                        gsl_vector * y,

                        gsl_vector * z,

                        gsl_movstat_workspace * w)

{

  if (x->size != y->size)

    {

      GSL_ERROR("input and output vectors must have same length", GSL_EBADLEN);

    }

  else if (z != NULL && x->size != z->size)

    {

      GSL_ERROR("input and output vectors must have same length", GSL_EBADLEN);

    }

  else

    {

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

      const int H = w->H; /* number of samples to left of current sample */

      const int J = w->J; /* number of samples to right of current sample */

      int i;

      double x1 = 0.0;    /* pad values for data edges */

      double xN = 0.0;

      double result[2];

      /* initialize accumulator */

      (accum->init)(w->K, w->state);

      /* pad initial window if necessary */

      if (endtype != GSL_MOVSTAT_END_TRUNCATE)

        {

          if (endtype == GSL_MOVSTAT_END_PADZERO)

            {

              x1 = 0.0;

              xN = 0.0;

            }

          else if (endtype == GSL_MOVSTAT_END_PADVALUE)

            {

              x1 = gsl_vector_get(x, 0);

              xN = gsl_vector_get(x, n - 1);

            }

          /* pad initial windows with H values */

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

            (accum->insert)(x1, w->state);

        }

      else if (accum->delete == NULL) /* FIXME XXX */

        {

          /* save last K - 1 samples of x for later (needed for in-place input/output) */

          int idx1 = GSL_MAX(n - J - H, 0);

          int idx2 = n - 1;

          for (i = idx1; i <= idx2; ++i)

            w->work[i - idx1] = gsl_vector_get(x, i);

        }

      /* process input vector and fill y(0:n - J - 1) */

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

        {

          double xi = gsl_vector_get(x, i);

          int idx = i - J;

          (accum->insert)(xi, w->state);

          if (idx >= 0)

            {

              (accum->get)(accum_params, result, w->state);

              gsl_vector_set(y, idx, result[0]);

              if (z != NULL)

                gsl_vector_set(z, idx, result[1]);

            }

        }

      if (endtype == GSL_MOVSTAT_END_TRUNCATE)

        {

          /* need to fill y(n-J:n-1) using shrinking windows */

          int idx1 = GSL_MAX(n - J, 0);

          int idx2 = n - 1;

          if (accum->delete == NULL)

            {

              int wsize = n - GSL_MAX(n - J - H, 0); /* size of work array */

              for (i = idx1; i <= idx2; ++i)

                {

                  int nsamp = n - GSL_MAX(i - H, 0); /* number of samples in this window */

                  int j;

                  (accum->init)(w->K, w->state);

                  for (j = wsize - nsamp; j < wsize; ++j)

                    (accum->insert)(w->work[j], w->state);

                  /* yi = acc_get [ work(i:K-2) ] */

                  (accum->get)(accum_params, result, w->state);

                  gsl_vector_set(y, i, result[0]);

                  if (z != NULL)

                    gsl_vector_set(z, i, result[1]);

                }

            }

          else

            {

              for (i = idx1; i <= idx2; ++i)

                {

                  if (i - H > 0)

                    {

                      /* delete oldest window sample as we move closer to edge */

                      (accum->delete)(w->state);

                    }

                  /* yi = acc_get [ work(i:K-2) ] */

                  (accum->get)(accum_params, result, w->state);

                  gsl_vector_set(y, i, result[0]);

                  if (z != NULL)

                    gsl_vector_set(z, i, result[1]);

                }

            }

        }

      else

        {

          /* pad final windows and fill y(n-J:n-1) */

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

            {

              int idx = n - J + i;

              (accum->insert)(xN, w->state);

              if (idx >= 0)

                {

                  (accum->get)(accum_params, result, w->state);

                  gsl_vector_set(y, idx, result[0]);

                  if (z != NULL)

                    gsl_vector_set(z, idx, result[1]);

                }

            }

        }

      return GSL_SUCCESS;

    }

}

/*

gsl_movstat_apply()

  Apply user-defined moving window function to input vector

Inputs: endtype - end point handling criteria

        F       - user-defined function

        x       - input vector, size n

        y       - output vector, size n

        w       - workspace

*/

int

gsl_movstat_apply(const gsl_movstat_end_t endtype, const gsl_movstat_function * F,

                  const gsl_vector * x, gsl_vector * y, gsl_movstat_workspace * w)

{

  int status = gsl_movstat_apply_accum(endtype, x, gsl_movstat_accum_userfunc, (void *) F, y, NULL, w);

  return status;

}