/* movstat/qnacc.c
*
* Moving window Q_n accumulator
*
* 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 <gsl/gsl_math.h>
#include <gsl/gsl_vector.h>
#include <gsl/gsl_errno.h>
#include <gsl/gsl_movstat.h>
#include <gsl/gsl_sort.h>
#include <gsl/gsl_statistics.h>
typedef double qnacc_type_t;
typedef qnacc_type_t ringbuf_type_t;
#include "ringbuf.c"
typedef struct
{
qnacc_type_t *window; /* linear array for current window */
qnacc_type_t *work; /* workspace, length 3*n */
int *work_int; /* integer workspace, length 5*n */
ringbuf *rbuf; /* ring buffer storing current window */
} qnacc_state_t;
static size_t
qnacc_size(const size_t n)
{
size_t size = 0;
size += sizeof(qnacc_state_t);
size += n * sizeof(qnacc_type_t); /* window */
size += 3 * n * sizeof(qnacc_type_t); /* work */
size += 5 * n * sizeof(int); /* work_int */
size += ringbuf_size(n);
return size;
}
static int
qnacc_init(const size_t n, void * vstate)
{
qnacc_state_t * state = (qnacc_state_t *) vstate;
state->window = (qnacc_type_t *) ((unsigned char *) vstate + sizeof(qnacc_state_t));
state->work = (qnacc_type_t *) ((unsigned char *) state->window + n * sizeof(qnacc_type_t));
state->work_int = (int *) ((unsigned char *) state->work + 3 * n * sizeof(qnacc_type_t));
state->rbuf = (ringbuf *) ((unsigned char *) state->work_int + 5 * n * sizeof(int));
ringbuf_init(n, state->rbuf);
return GSL_SUCCESS;
}
static int
qnacc_insert(const qnacc_type_t x, void * vstate)
{
qnacc_state_t * state = (qnacc_state_t *) vstate;
/* add new element to ring buffer */
ringbuf_insert(x, state->rbuf);
return GSL_SUCCESS;
}
static int
qnacc_delete(void * vstate)
{
qnacc_state_t * state = (qnacc_state_t *) vstate;
if (!ringbuf_is_empty(state->rbuf))
ringbuf_pop_back(state->rbuf);
return GSL_SUCCESS;
}
/* FIXME XXX: this is inefficient - could be improved by maintaining a sorted ring buffer */
static int
qnacc_get(void * params, qnacc_type_t * result, const void * vstate)
{
const qnacc_state_t * state = (const qnacc_state_t *) vstate;
size_t n = ringbuf_copy(state->window, state->rbuf);
(void) params;
gsl_sort(state->window, 1, n);
*result = gsl_stats_Qn_from_sorted_data(state->window, 1, n, state->work, state->work_int);
return GSL_SUCCESS;
}
static const gsl_movstat_accum qn_accum_type =
{
qnacc_size,
qnacc_init,
qnacc_insert,
qnacc_delete,
qnacc_get
};
const gsl_movstat_accum *gsl_movstat_accum_Qn = &qn_accum_type;