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Translation booster: pre-calculate Bessel funs. 

Former-commit-id: 85548558b3f65ac9e0a88c72adb4874dab98ca9e
This commit is contained in:
Marek Nečada 2020-01-23 00:10:34 +02:00
parent 8209e9df6e
commit effe59bc50
1 changed files with 69 additions and 15 deletions
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84
qpms/scatsys_translation_booster.c
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@ -1,37 +1,58 @@
// Functionality to speedup translation matrix computations in large finite arrays
// by caching Bessel function values etc.
#include "scatsystem.h"
#include <assert.h>
#include <stdlib.h>
#include "qpms_error.h"
#define SQ(x) ((x)*(x))
#define MAX(x, y) (((x) > (y)) ? (x) : (y))
typedef size_t ppid_t;
typedef size_t uoppid_t;
// Unordered pair ID. TODO get rid of redundancies
static inline uoppid_t uopairid(qpms_ss_pi_t pn_total, qpms_ss_pi_t p1, qpms_ss_pi_t p2) {
return pn_total * p1 + p2;
// Unordered exclusive pair ID count.
static inline uoppid_t uopairarr_len(qpms_ss_pi_t pn_total) {
return pn_total * (pn_total - 1) / 2;
}
// Unordered pair ID count. TODO get rid of redundancies.
static inline uoppid_t uopairarr_len(qpms_ss_pi_t pn_total) {
return SQ(pn_total);
// Unordered exclusive pair ID.
static inline uoppid_t uopairid(qpms_ss_pi_t pn_total, qpms_ss_pi_t p1, qpms_ss_pi_t p2) {
qpms_ss_pi_t hi, lo;
QPMS_ASSERT(p1 != p2);
if (p1 < p2) {
lo = p1;
hi = p2;
} else {
lo = p2;
hi = p1;
}
QPMS_ASSERT(lo >= 0);
QPMS_ASSERT(hi < pn_total);
return lo + hi * (hi - 1) / 2;
}
// Ordered pair ID.
static inline uoppid_t pairid(qpms_ss_pi_t pn_total, qpms_ss_pi_t p1, qpms_ss_pi_t p2) {
static inline ppid_t pairid(qpms_ss_pi_t pn_total, qpms_ss_pi_t p1, qpms_ss_pi_t p2) {
return pn_total * p1 + p2;
}
// Ordered pair ID count.
static inline uoppid_t pairarr_len(qpms_ss_pi_t pn_total) {
static inline ppid_t pairarr_len(qpms_ss_pi_t pn_total) {
return SQ(pn_total);
}
typedef struct qpms_scatsys_translation_booster {
double *r; // Unique distances array, indices are ppid_t
qpms_l_t *lMax_r; // lMaxes associated with the r's (use same indices as with r)
size_t r_count; // Number of different interparticle distances (length of r[])
size_t *r_map; // maps pairs to the corresponding distances (index of uoppid_t type)
} qpms_scatsys_translation_booster_t;
// Offsets of the Bessel function values: bessel_offsets_r[i] has the cumulative sums
// of 2*lMax_r[j]+2, j < i. bessel_offsets_r[r_count] is the total length of the
// Bessel function "cache"
size_t *bessel_offsets_r;
} booster_t;
struct uoppid_r_pair {
double r;
@ -70,17 +91,50 @@ static int cmp_double(const void *aa, const void *bb) {
QPMS_WTF; // NaN or similar
}
struct qpms_scatsys_translation_booster *qpms_scatsys_translation_booster_create(
booster_t *qpms_scatsys_translation_booster_create(
const qpms_scatsys_ss *ss) {
const qpms_ss_pi_t np = ss->p_count;
struct qpms_scatsys_translation_booster *b;
QPMS_CRASHING_MALLOC(b, sizeof(struct qpms_scatsys_translation_booster));
booster_t *b;
QPMS_CRASHING_MALLOC(b, sizeof(*b));
QPMS_CRASHING_MALLOC(b->r, sizeof(double) * uopairarr_len(np));
for(qpms_ss_pi_t i = 0; i < np; ++i)
for(qpms_ss_pi_t j = 0; j < np; ++i) // FIXME j < i when uopairid works as supposed
for(qpms_ss_pi_t j = 0; j < i; ++j)
b->r[uopairid(pn, i, j)] = cart3_dist(ss->p[i].pos, ss->p[j].pos);
b->r_count = sort_and_eliminate(b->r, uopairrarr_len(np), sizeof(double));
b->r_count = sort_and_eliminate(b->r, uopairrarr_len(np), sizeof(*b->r), cmp_double);
TODO;
QPMS_CRASHING_REALLOC(b->r, b->r_count * sizeof(*b->r));
QPMS_CRASHING_CALLOC(b->lMax_r, b->r_count, sizeof(*b->lMax_r));
for(qpms_ss_pi_t i = 0; i < np; ++i)
for(qpms_ss_pi_t j = 0; j < i; ++j) {
const uoppid_t pid = uopairid(pn, i, j);
const double r = cart3_dist(ss->p[i].pos, ss->p[j].pos);
double *rhit = bsearch(&r, b->r, b->r_count, sizeof(*b->r), cmp_double);
QPMS_ASSERT(rhit != NULL);
QPMS_ASSERT(rhit >= b->r);
const size_t ri = b->r_map[pid] = r_hit - b->r;
b->lMax_r[ri] = MAX(b->lMax_r[ri],
MAX(qpms_ss_bspec_pi(ss, i)->lMax, qpms_ss_bspec_pi(ss, j)->lMax));
}
QPMS_CRASHING_MALLOC(b->bessel_offset_r, (b->r_count + 1) * sizeof(*b->bessel_offset_r));
size_t bessel_offset = 0;
for(size_t ri = 0; ri < b->r_count; ++ri) {
b->bessel_offsets_r[ri] = bessel_offset;
bessel_offset += 2 * b->lMax_r[ri] + 2;
}
b->bessel_offsets_r[b->r_count] = bessel_offset;
return b;
}
static qpms_errno_t qpms_scatsys_translation_booster_eval_bessels(
const booster_t *b, complex double *target, complex double k // includes ref. ind. effect
) {
for(size_t ri = 0; ri < b->r_count; ++ri) {
QPMS_ENSURE_SUCCESS(qpms_sph_bessel_fill(QPMS_HANKEL_PLUS, // Is there a case for different J?
2*b->lMax_r[ri]+1, k * b->r[ri],
target + b->bessel_offsets_r[ri]));
return QPMS_SUCCESS;
}