1 /*
2 * Copyright (c) 2003, 2007-14 Matteo Frigo
3 * Copyright (c) 2003, 2007-14 Massachusetts Institute of Technology
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
18 *
19 */
20
21
22 /* Solve a DHT problem (Discrete Hartley Transform) via post-processing
23 of an R2HC problem. */
24
25 #include "rdft/rdft.h"
26
27 typedef struct {
28 solver super;
29 } S;
30
31 typedef struct {
32 plan_rdft super;
33 plan *cld;
34 INT os;
35 INT n;
36 } P;
37
apply(const plan * ego_,R * I,R * O)38 static void apply(const plan *ego_, R *I, R *O)
39 {
40 const P *ego = (const P *) ego_;
41 INT os = ego->os;
42 INT i, n = ego->n;
43
44 {
45 plan_rdft *cld = (plan_rdft *) ego->cld;
46 cld->apply((plan *) cld, I, O);
47 }
48
49 for (i = 1; i < n - i; ++i) {
50 E a, b;
51 a = O[os * i];
52 b = O[os * (n - i)];
53 #if FFT_SIGN == -1
54 O[os * i] = a - b;
55 O[os * (n - i)] = a + b;
56 #else
57 O[os * i] = a + b;
58 O[os * (n - i)] = a - b;
59 #endif
60 }
61 }
62
awake(plan * ego_,enum wakefulness wakefulness)63 static void awake(plan *ego_, enum wakefulness wakefulness)
64 {
65 P *ego = (P *) ego_;
66 X(plan_awake)(ego->cld, wakefulness);
67 }
68
destroy(plan * ego_)69 static void destroy(plan *ego_)
70 {
71 P *ego = (P *) ego_;
72 X(plan_destroy_internal)(ego->cld);
73 }
74
print(const plan * ego_,printer * p)75 static void print(const plan *ego_, printer *p)
76 {
77 const P *ego = (const P *) ego_;
78 p->print(p, "(dht-r2hc-%D%(%p%))", ego->n, ego->cld);
79 }
80
applicable0(const problem * p_,const planner * plnr)81 static int applicable0(const problem *p_, const planner *plnr)
82 {
83 const problem_rdft *p = (const problem_rdft *) p_;
84 return (1
85 && !NO_DHT_R2HCP(plnr)
86 && p->sz->rnk == 1
87 && p->vecsz->rnk == 0
88 && p->kind[0] == DHT
89 );
90 }
91
applicable(const solver * ego,const problem * p,const planner * plnr)92 static int applicable(const solver *ego, const problem *p, const planner *plnr)
93 {
94 UNUSED(ego);
95 return (!NO_SLOWP(plnr) && applicable0(p, plnr));
96 }
97
mkplan(const solver * ego_,const problem * p_,planner * plnr)98 static plan *mkplan(const solver *ego_, const problem *p_, planner *plnr)
99 {
100 P *pln;
101 const problem_rdft *p;
102 plan *cld;
103
104 static const plan_adt padt = {
105 X(rdft_solve), awake, print, destroy
106 };
107
108 if (!applicable(ego_, p_, plnr))
109 return (plan *)0;
110
111 p = (const problem_rdft *) p_;
112
113 /* NO_DHT_R2HC stops infinite loops with rdft-dht.c */
114 cld = X(mkplan_f_d)(plnr,
115 X(mkproblem_rdft_1)(p->sz, p->vecsz,
116 p->I, p->O, R2HC),
117 NO_DHT_R2HC, 0, 0);
118 if (!cld) return (plan *)0;
119
120 pln = MKPLAN_RDFT(P, &padt, apply);
121
122 pln->n = p->sz->dims[0].n;
123 pln->os = p->sz->dims[0].os;
124 pln->cld = cld;
125
126 pln->super.super.ops = cld->ops;
127 pln->super.super.ops.other += 4 * ((pln->n - 1)/2);
128 pln->super.super.ops.add += 2 * ((pln->n - 1)/2);
129
130 return &(pln->super.super);
131 }
132
133 /* constructor */
mksolver(void)134 static solver *mksolver(void)
135 {
136 static const solver_adt sadt = { PROBLEM_RDFT, mkplan, 0 };
137 S *slv = MKSOLVER(S, &sadt);
138 return &(slv->super);
139 }
140
X(dht_r2hc_register)141 void X(dht_r2hc_register)(planner *p)
142 {
143 REGISTER_SOLVER(p, mksolver());
144 }
145