2329
|
1 SUBROUTINE ZUNMBR( VECT, SIDE, TRANS, M, N, K, A, LDA, TAU, C, |
|
2 $ LDC, WORK, LWORK, INFO ) |
|
3 * |
7034
|
4 * -- LAPACK routine (version 3.1) -- |
|
5 * Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. |
|
6 * November 2006 |
2329
|
7 * |
|
8 * .. Scalar Arguments .. |
|
9 CHARACTER SIDE, TRANS, VECT |
|
10 INTEGER INFO, K, LDA, LDC, LWORK, M, N |
|
11 * .. |
|
12 * .. Array Arguments .. |
3333
|
13 COMPLEX*16 A( LDA, * ), C( LDC, * ), TAU( * ), WORK( * ) |
2329
|
14 * .. |
|
15 * |
|
16 * Purpose |
|
17 * ======= |
|
18 * |
|
19 * If VECT = 'Q', ZUNMBR overwrites the general complex M-by-N matrix C |
|
20 * with |
|
21 * SIDE = 'L' SIDE = 'R' |
|
22 * TRANS = 'N': Q * C C * Q |
|
23 * TRANS = 'C': Q**H * C C * Q**H |
|
24 * |
|
25 * If VECT = 'P', ZUNMBR overwrites the general complex M-by-N matrix C |
|
26 * with |
|
27 * SIDE = 'L' SIDE = 'R' |
|
28 * TRANS = 'N': P * C C * P |
|
29 * TRANS = 'C': P**H * C C * P**H |
|
30 * |
|
31 * Here Q and P**H are the unitary matrices determined by ZGEBRD when |
|
32 * reducing a complex matrix A to bidiagonal form: A = Q * B * P**H. Q |
|
33 * and P**H are defined as products of elementary reflectors H(i) and |
|
34 * G(i) respectively. |
|
35 * |
|
36 * Let nq = m if SIDE = 'L' and nq = n if SIDE = 'R'. Thus nq is the |
|
37 * order of the unitary matrix Q or P**H that is applied. |
|
38 * |
|
39 * If VECT = 'Q', A is assumed to have been an NQ-by-K matrix: |
|
40 * if nq >= k, Q = H(1) H(2) . . . H(k); |
|
41 * if nq < k, Q = H(1) H(2) . . . H(nq-1). |
|
42 * |
|
43 * If VECT = 'P', A is assumed to have been a K-by-NQ matrix: |
|
44 * if k < nq, P = G(1) G(2) . . . G(k); |
|
45 * if k >= nq, P = G(1) G(2) . . . G(nq-1). |
|
46 * |
|
47 * Arguments |
|
48 * ========= |
|
49 * |
|
50 * VECT (input) CHARACTER*1 |
|
51 * = 'Q': apply Q or Q**H; |
|
52 * = 'P': apply P or P**H. |
|
53 * |
|
54 * SIDE (input) CHARACTER*1 |
|
55 * = 'L': apply Q, Q**H, P or P**H from the Left; |
|
56 * = 'R': apply Q, Q**H, P or P**H from the Right. |
|
57 * |
|
58 * TRANS (input) CHARACTER*1 |
|
59 * = 'N': No transpose, apply Q or P; |
|
60 * = 'C': Conjugate transpose, apply Q**H or P**H. |
|
61 * |
|
62 * M (input) INTEGER |
|
63 * The number of rows of the matrix C. M >= 0. |
|
64 * |
|
65 * N (input) INTEGER |
|
66 * The number of columns of the matrix C. N >= 0. |
|
67 * |
|
68 * K (input) INTEGER |
|
69 * If VECT = 'Q', the number of columns in the original |
|
70 * matrix reduced by ZGEBRD. |
|
71 * If VECT = 'P', the number of rows in the original |
|
72 * matrix reduced by ZGEBRD. |
|
73 * K >= 0. |
|
74 * |
|
75 * A (input) COMPLEX*16 array, dimension |
|
76 * (LDA,min(nq,K)) if VECT = 'Q' |
|
77 * (LDA,nq) if VECT = 'P' |
|
78 * The vectors which define the elementary reflectors H(i) and |
|
79 * G(i), whose products determine the matrices Q and P, as |
|
80 * returned by ZGEBRD. |
|
81 * |
|
82 * LDA (input) INTEGER |
|
83 * The leading dimension of the array A. |
|
84 * If VECT = 'Q', LDA >= max(1,nq); |
|
85 * if VECT = 'P', LDA >= max(1,min(nq,K)). |
|
86 * |
|
87 * TAU (input) COMPLEX*16 array, dimension (min(nq,K)) |
|
88 * TAU(i) must contain the scalar factor of the elementary |
|
89 * reflector H(i) or G(i) which determines Q or P, as returned |
|
90 * by ZGEBRD in the array argument TAUQ or TAUP. |
|
91 * |
|
92 * C (input/output) COMPLEX*16 array, dimension (LDC,N) |
|
93 * On entry, the M-by-N matrix C. |
|
94 * On exit, C is overwritten by Q*C or Q**H*C or C*Q**H or C*Q |
|
95 * or P*C or P**H*C or C*P or C*P**H. |
|
96 * |
|
97 * LDC (input) INTEGER |
|
98 * The leading dimension of the array C. LDC >= max(1,M). |
|
99 * |
7034
|
100 * WORK (workspace/output) COMPLEX*16 array, dimension (MAX(1,LWORK)) |
2329
|
101 * On exit, if INFO = 0, WORK(1) returns the optimal LWORK. |
|
102 * |
|
103 * LWORK (input) INTEGER |
|
104 * The dimension of the array WORK. |
|
105 * If SIDE = 'L', LWORK >= max(1,N); |
7034
|
106 * if SIDE = 'R', LWORK >= max(1,M); |
|
107 * if N = 0 or M = 0, LWORK >= 1. |
|
108 * For optimum performance LWORK >= max(1,N*NB) if SIDE = 'L', |
|
109 * and LWORK >= max(1,M*NB) if SIDE = 'R', where NB is the |
|
110 * optimal blocksize. (NB = 0 if M = 0 or N = 0.) |
2329
|
111 * |
3333
|
112 * If LWORK = -1, then a workspace query is assumed; the routine |
|
113 * only calculates the optimal size of the WORK array, returns |
|
114 * this value as the first entry of the WORK array, and no error |
|
115 * message related to LWORK is issued by XERBLA. |
|
116 * |
2329
|
117 * INFO (output) INTEGER |
|
118 * = 0: successful exit |
|
119 * < 0: if INFO = -i, the i-th argument had an illegal value |
|
120 * |
|
121 * ===================================================================== |
|
122 * |
|
123 * .. Local Scalars .. |
3333
|
124 LOGICAL APPLYQ, LEFT, LQUERY, NOTRAN |
2329
|
125 CHARACTER TRANST |
3333
|
126 INTEGER I1, I2, IINFO, LWKOPT, MI, NB, NI, NQ, NW |
2329
|
127 * .. |
|
128 * .. External Functions .. |
|
129 LOGICAL LSAME |
3333
|
130 INTEGER ILAENV |
|
131 EXTERNAL LSAME, ILAENV |
2329
|
132 * .. |
|
133 * .. External Subroutines .. |
|
134 EXTERNAL XERBLA, ZUNMLQ, ZUNMQR |
|
135 * .. |
|
136 * .. Intrinsic Functions .. |
|
137 INTRINSIC MAX, MIN |
|
138 * .. |
|
139 * .. Executable Statements .. |
|
140 * |
|
141 * Test the input arguments |
|
142 * |
|
143 INFO = 0 |
|
144 APPLYQ = LSAME( VECT, 'Q' ) |
|
145 LEFT = LSAME( SIDE, 'L' ) |
|
146 NOTRAN = LSAME( TRANS, 'N' ) |
3333
|
147 LQUERY = ( LWORK.EQ.-1 ) |
2329
|
148 * |
|
149 * NQ is the order of Q or P and NW is the minimum dimension of WORK |
|
150 * |
|
151 IF( LEFT ) THEN |
|
152 NQ = M |
|
153 NW = N |
|
154 ELSE |
|
155 NQ = N |
|
156 NW = M |
|
157 END IF |
7034
|
158 IF( M.EQ.0 .OR. N.EQ.0 ) THEN |
|
159 NW = 0 |
|
160 END IF |
2329
|
161 IF( .NOT.APPLYQ .AND. .NOT.LSAME( VECT, 'P' ) ) THEN |
|
162 INFO = -1 |
|
163 ELSE IF( .NOT.LEFT .AND. .NOT.LSAME( SIDE, 'R' ) ) THEN |
|
164 INFO = -2 |
|
165 ELSE IF( .NOT.NOTRAN .AND. .NOT.LSAME( TRANS, 'C' ) ) THEN |
|
166 INFO = -3 |
|
167 ELSE IF( M.LT.0 ) THEN |
|
168 INFO = -4 |
|
169 ELSE IF( N.LT.0 ) THEN |
|
170 INFO = -5 |
|
171 ELSE IF( K.LT.0 ) THEN |
|
172 INFO = -6 |
|
173 ELSE IF( ( APPLYQ .AND. LDA.LT.MAX( 1, NQ ) ) .OR. |
|
174 $ ( .NOT.APPLYQ .AND. LDA.LT.MAX( 1, MIN( NQ, K ) ) ) ) |
|
175 $ THEN |
|
176 INFO = -8 |
|
177 ELSE IF( LDC.LT.MAX( 1, M ) ) THEN |
|
178 INFO = -11 |
3333
|
179 ELSE IF( LWORK.LT.MAX( 1, NW ) .AND. .NOT.LQUERY ) THEN |
2329
|
180 INFO = -13 |
|
181 END IF |
3333
|
182 * |
|
183 IF( INFO.EQ.0 ) THEN |
7034
|
184 IF( NW.GT.0 ) THEN |
|
185 IF( APPLYQ ) THEN |
|
186 IF( LEFT ) THEN |
|
187 NB = ILAENV( 1, 'ZUNMQR', SIDE // TRANS, M-1, N, M-1, |
|
188 $ -1 ) |
|
189 ELSE |
|
190 NB = ILAENV( 1, 'ZUNMQR', SIDE // TRANS, M, N-1, N-1, |
|
191 $ -1 ) |
|
192 END IF |
3333
|
193 ELSE |
7034
|
194 IF( LEFT ) THEN |
|
195 NB = ILAENV( 1, 'ZUNMLQ', SIDE // TRANS, M-1, N, M-1, |
|
196 $ -1 ) |
|
197 ELSE |
|
198 NB = ILAENV( 1, 'ZUNMLQ', SIDE // TRANS, M, N-1, N-1, |
|
199 $ -1 ) |
|
200 END IF |
3333
|
201 END IF |
7034
|
202 LWKOPT = MAX( 1, NW*NB ) |
3333
|
203 ELSE |
7034
|
204 LWKOPT = 1 |
3333
|
205 END IF |
|
206 WORK( 1 ) = LWKOPT |
|
207 END IF |
|
208 * |
2329
|
209 IF( INFO.NE.0 ) THEN |
|
210 CALL XERBLA( 'ZUNMBR', -INFO ) |
|
211 RETURN |
3333
|
212 ELSE IF( LQUERY ) THEN |
7034
|
213 RETURN |
2329
|
214 END IF |
|
215 * |
|
216 * Quick return if possible |
|
217 * |
|
218 IF( M.EQ.0 .OR. N.EQ.0 ) |
|
219 $ RETURN |
|
220 * |
|
221 IF( APPLYQ ) THEN |
|
222 * |
|
223 * Apply Q |
|
224 * |
|
225 IF( NQ.GE.K ) THEN |
|
226 * |
|
227 * Q was determined by a call to ZGEBRD with nq >= k |
|
228 * |
|
229 CALL ZUNMQR( SIDE, TRANS, M, N, K, A, LDA, TAU, C, LDC, |
|
230 $ WORK, LWORK, IINFO ) |
|
231 ELSE IF( NQ.GT.1 ) THEN |
|
232 * |
|
233 * Q was determined by a call to ZGEBRD with nq < k |
|
234 * |
|
235 IF( LEFT ) THEN |
|
236 MI = M - 1 |
|
237 NI = N |
|
238 I1 = 2 |
|
239 I2 = 1 |
|
240 ELSE |
|
241 MI = M |
|
242 NI = N - 1 |
|
243 I1 = 1 |
|
244 I2 = 2 |
|
245 END IF |
|
246 CALL ZUNMQR( SIDE, TRANS, MI, NI, NQ-1, A( 2, 1 ), LDA, TAU, |
|
247 $ C( I1, I2 ), LDC, WORK, LWORK, IINFO ) |
|
248 END IF |
|
249 ELSE |
|
250 * |
|
251 * Apply P |
|
252 * |
|
253 IF( NOTRAN ) THEN |
|
254 TRANST = 'C' |
|
255 ELSE |
|
256 TRANST = 'N' |
|
257 END IF |
|
258 IF( NQ.GT.K ) THEN |
|
259 * |
|
260 * P was determined by a call to ZGEBRD with nq > k |
|
261 * |
|
262 CALL ZUNMLQ( SIDE, TRANST, M, N, K, A, LDA, TAU, C, LDC, |
|
263 $ WORK, LWORK, IINFO ) |
|
264 ELSE IF( NQ.GT.1 ) THEN |
|
265 * |
|
266 * P was determined by a call to ZGEBRD with nq <= k |
|
267 * |
|
268 IF( LEFT ) THEN |
|
269 MI = M - 1 |
|
270 NI = N |
|
271 I1 = 2 |
|
272 I2 = 1 |
|
273 ELSE |
|
274 MI = M |
|
275 NI = N - 1 |
|
276 I1 = 1 |
|
277 I2 = 2 |
|
278 END IF |
|
279 CALL ZUNMLQ( SIDE, TRANST, MI, NI, NQ-1, A( 1, 2 ), LDA, |
|
280 $ TAU, C( I1, I2 ), LDC, WORK, LWORK, IINFO ) |
|
281 END IF |
|
282 END IF |
3333
|
283 WORK( 1 ) = LWKOPT |
2329
|
284 RETURN |
|
285 * |
|
286 * End of ZUNMBR |
|
287 * |
|
288 END |