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
|
/* ../../../dependencies/lapack/src/slarz.f -- translated by f2c (version 20061008).
You must link the resulting object file with libf2c:
on Microsoft Windows system, link with libf2c.lib;
on Linux or Unix systems, link with .../path/to/libf2c.a -lm
or, if you install libf2c.a in a standard place, with -lf2c -lm
-- in that order, at the end of the command line, as in
cc *.o -lf2c -lm
Source for libf2c is in /netlib/f2c/libf2c.zip, e.g.,
http://www.netlib.org/f2c/libf2c.zip
*/
#include "f2c.h"
/* Table of constant values */
static integer c__1 = 1;
static real c_b5 = 1.f;
/* Subroutine */ int slarz_(char *side, integer *m, integer *n, integer *l,
real *v, integer *incv, real *tau, real *c__, integer *ldc, real *
work, ftnlen side_len)
{
/* System generated locals */
integer c_dim1, c_offset;
real r__1;
/* Local variables */
extern /* Subroutine */ int sger_(integer *, integer *, real *, real *,
integer *, real *, integer *, real *, integer *);
extern logical lsame_(char *, char *, ftnlen, ftnlen);
extern /* Subroutine */ int sgemv_(char *, integer *, integer *, real *,
real *, integer *, real *, integer *, real *, real *, integer *,
ftnlen), scopy_(integer *, real *, integer *, real *, integer *),
saxpy_(integer *, real *, real *, integer *, real *, integer *);
/* -- LAPACK routine (version 3.0) -- */
/* Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd., */
/* Courant Institute, Argonne National Lab, and Rice University */
/* June 30, 1999 */
/* .. Scalar Arguments .. */
/* .. */
/* .. Array Arguments .. */
/* .. */
/* Purpose */
/* ======= */
/* SLARZ applies a real elementary reflector H to a real M-by-N */
/* matrix C, from either the left or the right. H is represented in the */
/* form */
/* H = I - tau * v * v' */
/* where tau is a real scalar and v is a real vector. */
/* If tau = 0, then H is taken to be the unit matrix. */
/* H is a product of k elementary reflectors as returned by STZRZF. */
/* Arguments */
/* ========= */
/* SIDE (input) CHARACTER*1 */
/* = 'L': form H * C */
/* = 'R': form C * H */
/* M (input) INTEGER */
/* The number of rows of the matrix C. */
/* N (input) INTEGER */
/* The number of columns of the matrix C. */
/* L (input) INTEGER */
/* The number of entries of the vector V containing */
/* the meaningful part of the Householder vectors. */
/* If SIDE = 'L', M >= L >= 0, if SIDE = 'R', N >= L >= 0. */
/* V (input) REAL array, dimension (1+(L-1)*abs(INCV)) */
/* The vector v in the representation of H as returned by */
/* STZRZF. V is not used if TAU = 0. */
/* INCV (input) INTEGER */
/* The increment between elements of v. INCV <> 0. */
/* TAU (input) REAL */
/* The value tau in the representation of H. */
/* C (input/output) REAL array, dimension (LDC,N) */
/* On entry, the M-by-N matrix C. */
/* On exit, C is overwritten by the matrix H * C if SIDE = 'L', */
/* or C * H if SIDE = 'R'. */
/* LDC (input) INTEGER */
/* The leading dimension of the array C. LDC >= max(1,M). */
/* WORK (workspace) REAL array, dimension */
/* (N) if SIDE = 'L' */
/* or (M) if SIDE = 'R' */
/* Further Details */
/* =============== */
/* Based on contributions by */
/* A. Petitet, Computer Science Dept., Univ. of Tenn., Knoxville, USA */
/* ===================================================================== */
/* .. Parameters .. */
/* .. */
/* .. External Subroutines .. */
/* .. */
/* .. External Functions .. */
/* .. */
/* .. Executable Statements .. */
/* Parameter adjustments */
--v;
c_dim1 = *ldc;
c_offset = 1 + c_dim1;
c__ -= c_offset;
--work;
/* Function Body */
if (lsame_(side, "L", (ftnlen)1, (ftnlen)1)) {
/* Form H * C */
if (*tau != 0.f) {
/* w( 1:n ) = C( 1, 1:n ) */
scopy_(n, &c__[c_offset], ldc, &work[1], &c__1);
/* w( 1:n ) = w( 1:n ) + C( m-l+1:m, 1:n )' * v( 1:l ) */
sgemv_("Transpose", l, n, &c_b5, &c__[*m - *l + 1 + c_dim1], ldc,
&v[1], incv, &c_b5, &work[1], &c__1, (ftnlen)9);
/* C( 1, 1:n ) = C( 1, 1:n ) - tau * w( 1:n ) */
r__1 = -(*tau);
saxpy_(n, &r__1, &work[1], &c__1, &c__[c_offset], ldc);
/* C( m-l+1:m, 1:n ) = C( m-l+1:m, 1:n ) - ... */
/* tau * v( 1:l ) * w( 1:n )' */
r__1 = -(*tau);
sger_(l, n, &r__1, &v[1], incv, &work[1], &c__1, &c__[*m - *l + 1
+ c_dim1], ldc);
}
} else {
/* Form C * H */
if (*tau != 0.f) {
/* w( 1:m ) = C( 1:m, 1 ) */
scopy_(m, &c__[c_offset], &c__1, &work[1], &c__1);
/* w( 1:m ) = w( 1:m ) + C( 1:m, n-l+1:n, 1:n ) * v( 1:l ) */
sgemv_("No transpose", m, l, &c_b5, &c__[(*n - *l + 1) * c_dim1 +
1], ldc, &v[1], incv, &c_b5, &work[1], &c__1, (ftnlen)12);
/* C( 1:m, 1 ) = C( 1:m, 1 ) - tau * w( 1:m ) */
r__1 = -(*tau);
saxpy_(m, &r__1, &work[1], &c__1, &c__[c_offset], &c__1);
/* C( 1:m, n-l+1:n ) = C( 1:m, n-l+1:n ) - ... */
/* tau * w( 1:m ) * v( 1:l )' */
r__1 = -(*tau);
sger_(m, l, &r__1, &work[1], &c__1, &v[1], incv, &c__[(*n - *l +
1) * c_dim1 + 1], ldc);
}
}
return 0;
/* End of SLARZ */
} /* slarz_ */
|
