1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
|
/*
-- MAGMA (version 2.5.4) --
Univ. of Tennessee, Knoxville
Univ. of California, Berkeley
Univ. of Colorado, Denver
@date October 2020
@generated from sparse/control/magma_zselect.cpp, normal z -> d, Thu Oct 8 23:05:51 2020
@author Hartwig Anzt
*/
// in this file, many routines are taken from
// the IO functions provided by MatrixMarket
#include "magmasparse_internal.h"
#define SWAP(a, b) { tmp = a; a = b; b = tmp; }
magma_int_t
magma_dpartition(
double *a,
magma_int_t size,
magma_int_t pivot,
magma_queue_t queue ) {
// using std::swap;
double tmp;
double pivotValue = a[pivot];
SWAP(a[pivot], a[size-1]);
int storePos = 0;
for(int loadPos=0; loadPos < size-1; loadPos++) {
if( MAGMA_D_ABS(a[loadPos]) < MAGMA_D_ABS(pivotValue) ) {
SWAP(a[loadPos], a[storePos]);
storePos++;
}
}
SWAP(a[storePos], a[size-1]);
return storePos;
}
magma_int_t
magma_dmedian5(
double *a,
magma_queue_t queue ) {
// using std::swap;
double tmp;
double a0 = a[0];
double a1 = a[1];
double a2 = a[2];
double a3 = a[3];
double a4 = a[4];
if ( MAGMA_D_ABS(a1) < MAGMA_D_ABS( a0))
SWAP( a0, a1);
if ( MAGMA_D_ABS(a2) < MAGMA_D_ABS( a0))
SWAP( a0, a2);
if ( MAGMA_D_ABS(a3) < MAGMA_D_ABS( a0))
SWAP( a0, a3);
if ( MAGMA_D_ABS(a4) < MAGMA_D_ABS( a0))
SWAP( a0, a4);
if ( MAGMA_D_ABS(a2) < MAGMA_D_ABS( a1))
SWAP( a1, a2);
if ( MAGMA_D_ABS(a3) < MAGMA_D_ABS( a1))
SWAP( a1, a3);
if ( MAGMA_D_ABS(a4) < MAGMA_D_ABS( a1))
SWAP( a1, a4);
if ( MAGMA_D_ABS(a3) < MAGMA_D_ABS( a2))
SWAP( a2, a3);
if ( MAGMA_D_ABS(a4) < MAGMA_D_ABS( a2))
SWAP( a2, a4);
if ( MAGMA_D_ABS(a2) == MAGMA_D_ABS(a[0]))
return 0;
if ( MAGMA_D_ABS(a2) == MAGMA_D_ABS(a[1]))
return 1;
if ( MAGMA_D_ABS(a2) == MAGMA_D_ABS(a[2]))
return 2;
if ( MAGMA_D_ABS(a2) == MAGMA_D_ABS(a[3]))
return 3;
// else if ( MAGMA_D_ABS(a2) == MAGMA_D_ABS(a[4]))
return 4;
}
/**
Purpose
-------
An efficient implementation of Blum, Floyd,
Pratt, Rivest, and Tarjan's worst-case linear
selection algorithm
Derrick Coetzee, webmaster@moonflare.com
January 22, 2004
http://moonflare.com/code/select/select.pdf
Arguments
---------
@param[in,out]
a double*
array to select from
@param[in]
size magma_int_t
size of array
@param[in]
k magma_int_t
k-th smallest element
@param[in]
queue magma_queue_t
Queue to execute in.
@ingroup magmasparse_daux
********************************************************************/
extern "C"
magma_int_t
magma_dselect(
double *a,
magma_int_t size,
magma_int_t k,
magma_queue_t queue ) {
magma_int_t info = 0;
// using std::swap;
double tmp;
if (size < 5) {
for (int i=0; i<size; i++)
for (int j=i+1; j<size; j++)
if (MAGMA_D_ABS(a[j]) < MAGMA_D_ABS(a[i]))
SWAP(a[i], a[j]);
return info;
}
int groupNum = 0;
double *group = a;
for( ; groupNum*5 <= size-5; group += 5, groupNum++) {
SWAP(group[magma_dmedian5(group, queue)], a[groupNum]);
}
int numMedians = size/5;
// Index of median of medians
int MOMIdx = numMedians/2;
magma_dselect(a, numMedians, MOMIdx, queue);
int newMOMIdx = magma_dpartition(a, size, MOMIdx, queue);
if (k != newMOMIdx) {
if (k < newMOMIdx) {
magma_dselect(a, newMOMIdx, k, queue);
} else /* if (k > newMOMIdx) */ {
magma_dselect(a + newMOMIdx + 1, size - newMOMIdx - 1, k - newMOMIdx - 1, queue);
}
}
return info;
}
/**
Purpose
-------
An efficient implementation of Blum, Floyd,
Pratt, Rivest, and Tarjan's worst-case linear
selection algorithm
Derrick Coetzee, webmaster@moonflare.com
January 22, 2004
http://moonflare.com/code/select/select.pdf
Arguments
---------
@param[in,out]
a double*
array to select from
@param[in]
size magma_int_t
size of array
@param[in]
k magma_int_t
k-th smallest element
@param[in]
queue magma_queue_t
Queue to execute in.
@ingroup magmasparse_daux
********************************************************************/
extern "C"
magma_int_t
magma_dselectrandom(
double *a,
magma_int_t size,
magma_int_t k,
magma_queue_t queue ) {
magma_int_t info = 0;
//using std::swap;
double tmp;
if (size < 5) {
for (int i=0; i<size; i++)
for (int j=i+1; j<size; j++)
if (MAGMA_D_ABS(a[j]) < MAGMA_D_ABS(a[i]))
SWAP(a[i], a[j]);
return info;
}
int pivotIdx = magma_dpartition(a, size, rand() % size, queue);
if (k != pivotIdx) {
if (k < pivotIdx) {
magma_dselectrandom(a, pivotIdx, k, queue);
} else /* if (k > pivotIdx) */ {
magma_dselectrandom(a + pivotIdx + 1, size - pivotIdx - 1, k - pivotIdx - 1, queue);
}
}
return info;
}
|
