aboutsummaryrefslogtreecommitdiffstats
path: root/contrib/libs/clapack/dlarzb.c
blob: 2cf3e7fae2ed1312d9c0c067dcee7b9ab0b26223 (plain) (blame)
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
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
/* dlarzb.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"
#include "blaswrap.h"

/* Table of constant values */

static integer c__1 = 1;
static doublereal c_b13 = 1.;
static doublereal c_b23 = -1.;

/* Subroutine */ int dlarzb_(char *side, char *trans, char *direct, char *
	storev, integer *m, integer *n, integer *k, integer *l, doublereal *v, 
	 integer *ldv, doublereal *t, integer *ldt, doublereal *c__, integer *
	ldc, doublereal *work, integer *ldwork)
{
    /* System generated locals */
    integer c_dim1, c_offset, t_dim1, t_offset, v_dim1, v_offset, work_dim1, 
	    work_offset, i__1, i__2;

    /* Local variables */
    integer i__, j, info;
    extern /* Subroutine */ int dgemm_(char *, char *, integer *, integer *, 
	    integer *, doublereal *, doublereal *, integer *, doublereal *, 
	    integer *, doublereal *, doublereal *, integer *);
    extern logical lsame_(char *, char *);
    extern /* Subroutine */ int dcopy_(integer *, doublereal *, integer *, 
	    doublereal *, integer *), dtrmm_(char *, char *, char *, char *, 
	    integer *, integer *, doublereal *, doublereal *, integer *, 
	    doublereal *, integer *), xerbla_(
	    char *, integer *);
    char transt[1];


/*  -- LAPACK routine (version 3.2) -- */
/*     Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
/*     November 2006 */

/*     .. Scalar Arguments .. */
/*     .. */
/*     .. Array Arguments .. */
/*     .. */

/*  Purpose */
/*  ======= */

/*  DLARZB applies a real block reflector H or its transpose H**T to */
/*  a real distributed M-by-N  C from the left or the right. */

/*  Currently, only STOREV = 'R' and DIRECT = 'B' are supported. */

/*  Arguments */
/*  ========= */

/*  SIDE    (input) CHARACTER*1 */
/*          = 'L': apply H or H' from the Left */
/*          = 'R': apply H or H' from the Right */

/*  TRANS   (input) CHARACTER*1 */
/*          = 'N': apply H (No transpose) */
/*          = 'C': apply H' (Transpose) */

/*  DIRECT  (input) CHARACTER*1 */
/*          Indicates how H is formed from a product of elementary */
/*          reflectors */
/*          = 'F': H = H(1) H(2) . . . H(k) (Forward, not supported yet) */
/*          = 'B': H = H(k) . . . H(2) H(1) (Backward) */

/*  STOREV  (input) CHARACTER*1 */
/*          Indicates how the vectors which define the elementary */
/*          reflectors are stored: */
/*          = 'C': Columnwise                        (not supported yet) */
/*          = 'R': Rowwise */

/*  M       (input) INTEGER */
/*          The number of rows of the matrix C. */

/*  N       (input) INTEGER */
/*          The number of columns of the matrix C. */

/*  K       (input) INTEGER */
/*          The order of the matrix T (= the number of elementary */
/*          reflectors whose product defines the block reflector). */

/*  L       (input) INTEGER */
/*          The number of columns of the matrix V containing the */
/*          meaningful part of the Householder reflectors. */
/*          If SIDE = 'L', M >= L >= 0, if SIDE = 'R', N >= L >= 0. */

/*  V       (input) DOUBLE PRECISION array, dimension (LDV,NV). */
/*          If STOREV = 'C', NV = K; if STOREV = 'R', NV = L. */

/*  LDV     (input) INTEGER */
/*          The leading dimension of the array V. */
/*          If STOREV = 'C', LDV >= L; if STOREV = 'R', LDV >= K. */

/*  T       (input) DOUBLE PRECISION array, dimension (LDT,K) */
/*          The triangular K-by-K matrix T in the representation of the */
/*          block reflector. */

/*  LDT     (input) INTEGER */
/*          The leading dimension of the array T. LDT >= K. */

/*  C       (input/output) DOUBLE PRECISION array, dimension (LDC,N) */
/*          On entry, the M-by-N matrix C. */
/*          On exit, C is overwritten by H*C or H'*C or C*H or C*H'. */

/*  LDC     (input) INTEGER */
/*          The leading dimension of the array C. LDC >= max(1,M). */

/*  WORK    (workspace) DOUBLE PRECISION array, dimension (LDWORK,K) */

/*  LDWORK  (input) INTEGER */
/*          The leading dimension of the array WORK. */
/*          If SIDE = 'L', LDWORK >= max(1,N); */
/*          if SIDE = 'R', LDWORK >= max(1,M). */

/*  Further Details */
/*  =============== */

/*  Based on contributions by */
/*    A. Petitet, Computer Science Dept., Univ. of Tenn., Knoxville, USA */

/*  ===================================================================== */

/*     .. Parameters .. */
/*     .. */
/*     .. Local Scalars .. */
/*     .. */
/*     .. External Functions .. */
/*     .. */
/*     .. External Subroutines .. */
/*     .. */
/*     .. Executable Statements .. */

/*     Quick return if possible */

    /* Parameter adjustments */
    v_dim1 = *ldv;
    v_offset = 1 + v_dim1;
    v -= v_offset;
    t_dim1 = *ldt;
    t_offset = 1 + t_dim1;
    t -= t_offset;
    c_dim1 = *ldc;
    c_offset = 1 + c_dim1;
    c__ -= c_offset;
    work_dim1 = *ldwork;
    work_offset = 1 + work_dim1;
    work -= work_offset;

    /* Function Body */
    if (*m <= 0 || *n <= 0) {
	return 0;
    }

/*     Check for currently supported options */

    info = 0;
    if (! lsame_(direct, "B")) {
	info = -3;
    } else if (! lsame_(storev, "R")) {
	info = -4;
    }
    if (info != 0) {
	i__1 = -info;
	xerbla_("DLARZB", &i__1);
	return 0;
    }

    if (lsame_(trans, "N")) {
	*(unsigned char *)transt = 'T';
    } else {
	*(unsigned char *)transt = 'N';
    }

    if (lsame_(side, "L")) {

/*        Form  H * C  or  H' * C */

/*        W( 1:n, 1:k ) = C( 1:k, 1:n )' */

	i__1 = *k;
	for (j = 1; j <= i__1; ++j) {
	    dcopy_(n, &c__[j + c_dim1], ldc, &work[j * work_dim1 + 1], &c__1);
/* L10: */
	}

/*        W( 1:n, 1:k ) = W( 1:n, 1:k ) + ... */
/*                        C( m-l+1:m, 1:n )' * V( 1:k, 1:l )' */

	if (*l > 0) {
	    dgemm_("Transpose", "Transpose", n, k, l, &c_b13, &c__[*m - *l + 
		    1 + c_dim1], ldc, &v[v_offset], ldv, &c_b13, &work[
		    work_offset], ldwork);
	}

/*        W( 1:n, 1:k ) = W( 1:n, 1:k ) * T'  or  W( 1:m, 1:k ) * T */

	dtrmm_("Right", "Lower", transt, "Non-unit", n, k, &c_b13, &t[
		t_offset], ldt, &work[work_offset], ldwork);

/*        C( 1:k, 1:n ) = C( 1:k, 1:n ) - W( 1:n, 1:k )' */

	i__1 = *n;
	for (j = 1; j <= i__1; ++j) {
	    i__2 = *k;
	    for (i__ = 1; i__ <= i__2; ++i__) {
		c__[i__ + j * c_dim1] -= work[j + i__ * work_dim1];
/* L20: */
	    }
/* L30: */
	}

/*        C( m-l+1:m, 1:n ) = C( m-l+1:m, 1:n ) - ... */
/*                            V( 1:k, 1:l )' * W( 1:n, 1:k )' */

	if (*l > 0) {
	    dgemm_("Transpose", "Transpose", l, n, k, &c_b23, &v[v_offset], 
		    ldv, &work[work_offset], ldwork, &c_b13, &c__[*m - *l + 1 
		    + c_dim1], ldc);
	}

    } else if (lsame_(side, "R")) {

/*        Form  C * H  or  C * H' */

/*        W( 1:m, 1:k ) = C( 1:m, 1:k ) */

	i__1 = *k;
	for (j = 1; j <= i__1; ++j) {
	    dcopy_(m, &c__[j * c_dim1 + 1], &c__1, &work[j * work_dim1 + 1], &
		    c__1);
/* L40: */
	}

/*        W( 1:m, 1:k ) = W( 1:m, 1:k ) + ... */
/*                        C( 1:m, n-l+1:n ) * V( 1:k, 1:l )' */

	if (*l > 0) {
	    dgemm_("No transpose", "Transpose", m, k, l, &c_b13, &c__[(*n - *
		    l + 1) * c_dim1 + 1], ldc, &v[v_offset], ldv, &c_b13, &
		    work[work_offset], ldwork);
	}

/*        W( 1:m, 1:k ) = W( 1:m, 1:k ) * T  or  W( 1:m, 1:k ) * T' */

	dtrmm_("Right", "Lower", trans, "Non-unit", m, k, &c_b13, &t[t_offset]
, ldt, &work[work_offset], ldwork);

/*        C( 1:m, 1:k ) = C( 1:m, 1:k ) - W( 1:m, 1:k ) */

	i__1 = *k;
	for (j = 1; j <= i__1; ++j) {
	    i__2 = *m;
	    for (i__ = 1; i__ <= i__2; ++i__) {
		c__[i__ + j * c_dim1] -= work[i__ + j * work_dim1];
/* L50: */
	    }
/* L60: */
	}

/*        C( 1:m, n-l+1:n ) = C( 1:m, n-l+1:n ) - ... */
/*                            W( 1:m, 1:k ) * V( 1:k, 1:l ) */

	if (*l > 0) {
	    dgemm_("No transpose", "No transpose", m, l, k, &c_b23, &work[
		    work_offset], ldwork, &v[v_offset], ldv, &c_b13, &c__[(*n 
		    - *l + 1) * c_dim1 + 1], ldc);
	}

    }

    return 0;

/*     End of DLARZB */

} /* dlarzb_ */