circuitpython-ulab/code/filter.c
2020-02-06 15:53:49 -06:00

59 lines
2.1 KiB
C

/*
* This file is part of the micropython-ulab project,
*
* https://github.com/v923z/micropython-ulab
*
* The MIT License (MIT)
*
* Copyright (c) 2020 Jeff Epler for Adafruit Industries
*/
#include <math.h>
#include <stdlib.h>
#include <string.h>
#include "py/obj.h"
#include "py/runtime.h"
#include "compat.h"
#include "filter.h"
mp_obj_t filter_convolve(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
static const mp_arg_t allowed_args[] = {
{ MP_QSTR_a, MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE } },
{ MP_QSTR_v, MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE } },
};
mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
mp_arg_parse_all(2, pos_args, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
if(!mp_obj_is_type(args[0].u_obj, &ulab_ndarray_type) || !mp_obj_is_type(args[1].u_obj, &ulab_ndarray_type)) {
mp_raise_TypeError(translate("convolve arguments must be ndarrays"));
}
ndarray_obj_t *a = MP_OBJ_TO_PTR(args[0].u_obj);
ndarray_obj_t *c = MP_OBJ_TO_PTR(args[1].u_obj);
int len_a = a->array->len;
int len_c = c->array->len;
if(len_a == 0 || len_c == 0) {
mp_raise_TypeError(translate("convolve arguments must not be empty"));
}
int len = len_a + len_c - 1; // convolve mode "full"
ndarray_obj_t *out = create_new_ndarray(1, len, NDARRAY_FLOAT);
mp_float_t *outptr = out->array->items;
int off = len_c-1;
for(int k=-off; k<len-off; k++) {
mp_float_t accum = (mp_float_t)0;
int top_n = MIN(len_c, len_a - k);
int bot_n = MAX(-k, 0);
for(int n=bot_n; n<top_n; n++) {
int idx_c = len_c - n - 1;
int idx_a = n+k;
mp_float_t ai = idx_a >= 0 && idx_a < len_a ? ndarray_get_float_value(a->array->items, c->array->typecode, idx_a) : (mp_float_t)0;
mp_float_t ci = idx_c >= 0 && idx_c < len_c ? ndarray_get_float_value(c->array->items, c->array->typecode, idx_c) : (mp_float_t)0;
accum += ai * ci;
}
*outptr++ = accum;
}
return out;
}