1 | *> \brief \b SORMR3 |
---|
2 | * |
---|
3 | * =========== DOCUMENTATION =========== |
---|
4 | * |
---|
5 | * Online html documentation available at |
---|
6 | * http://www.netlib.org/lapack/explore-html/ |
---|
7 | * |
---|
8 | *> \htmlonly |
---|
9 | *> Download SORMR3 + dependencies |
---|
10 | *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/sormr3.f"> |
---|
11 | *> [TGZ]</a> |
---|
12 | *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/sormr3.f"> |
---|
13 | *> [ZIP]</a> |
---|
14 | *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/sormr3.f"> |
---|
15 | *> [TXT]</a> |
---|
16 | *> \endhtmlonly |
---|
17 | * |
---|
18 | * Definition: |
---|
19 | * =========== |
---|
20 | * |
---|
21 | * SUBROUTINE SORMR3( SIDE, TRANS, M, N, K, L, A, LDA, TAU, C, LDC, |
---|
22 | * WORK, INFO ) |
---|
23 | * |
---|
24 | * .. Scalar Arguments .. |
---|
25 | * CHARACTER SIDE, TRANS |
---|
26 | * INTEGER INFO, K, L, LDA, LDC, M, N |
---|
27 | * .. |
---|
28 | * .. Array Arguments .. |
---|
29 | * REAL A( LDA, * ), C( LDC, * ), TAU( * ), WORK( * ) |
---|
30 | * .. |
---|
31 | * |
---|
32 | * |
---|
33 | *> \par Purpose: |
---|
34 | * ============= |
---|
35 | *> |
---|
36 | *> \verbatim |
---|
37 | *> |
---|
38 | *> SORMR3 overwrites the general real m by n matrix C with |
---|
39 | *> |
---|
40 | *> Q * C if SIDE = 'L' and TRANS = 'N', or |
---|
41 | *> |
---|
42 | *> Q**T* C if SIDE = 'L' and TRANS = 'C', or |
---|
43 | *> |
---|
44 | *> C * Q if SIDE = 'R' and TRANS = 'N', or |
---|
45 | *> |
---|
46 | *> C * Q**T if SIDE = 'R' and TRANS = 'C', |
---|
47 | *> |
---|
48 | *> where Q is a real orthogonal matrix defined as the product of k |
---|
49 | *> elementary reflectors |
---|
50 | *> |
---|
51 | *> Q = H(1) H(2) . . . H(k) |
---|
52 | *> |
---|
53 | *> as returned by STZRZF. Q is of order m if SIDE = 'L' and of order n |
---|
54 | *> if SIDE = 'R'. |
---|
55 | *> \endverbatim |
---|
56 | * |
---|
57 | * Arguments: |
---|
58 | * ========== |
---|
59 | * |
---|
60 | *> \param[in] SIDE |
---|
61 | *> \verbatim |
---|
62 | *> SIDE is CHARACTER*1 |
---|
63 | *> = 'L': apply Q or Q**T from the Left |
---|
64 | *> = 'R': apply Q or Q**T from the Right |
---|
65 | *> \endverbatim |
---|
66 | *> |
---|
67 | *> \param[in] TRANS |
---|
68 | *> \verbatim |
---|
69 | *> TRANS is CHARACTER*1 |
---|
70 | *> = 'N': apply Q (No transpose) |
---|
71 | *> = 'T': apply Q**T (Transpose) |
---|
72 | *> \endverbatim |
---|
73 | *> |
---|
74 | *> \param[in] M |
---|
75 | *> \verbatim |
---|
76 | *> M is INTEGER |
---|
77 | *> The number of rows of the matrix C. M >= 0. |
---|
78 | *> \endverbatim |
---|
79 | *> |
---|
80 | *> \param[in] N |
---|
81 | *> \verbatim |
---|
82 | *> N is INTEGER |
---|
83 | *> The number of columns of the matrix C. N >= 0. |
---|
84 | *> \endverbatim |
---|
85 | *> |
---|
86 | *> \param[in] K |
---|
87 | *> \verbatim |
---|
88 | *> K is INTEGER |
---|
89 | *> The number of elementary reflectors whose product defines |
---|
90 | *> the matrix Q. |
---|
91 | *> If SIDE = 'L', M >= K >= 0; |
---|
92 | *> if SIDE = 'R', N >= K >= 0. |
---|
93 | *> \endverbatim |
---|
94 | *> |
---|
95 | *> \param[in] L |
---|
96 | *> \verbatim |
---|
97 | *> L is INTEGER |
---|
98 | *> The number of columns of the matrix A containing |
---|
99 | *> the meaningful part of the Householder reflectors. |
---|
100 | *> If SIDE = 'L', M >= L >= 0, if SIDE = 'R', N >= L >= 0. |
---|
101 | *> \endverbatim |
---|
102 | *> |
---|
103 | *> \param[in] A |
---|
104 | *> \verbatim |
---|
105 | *> A is REAL array, dimension |
---|
106 | *> (LDA,M) if SIDE = 'L', |
---|
107 | *> (LDA,N) if SIDE = 'R' |
---|
108 | *> The i-th row must contain the vector which defines the |
---|
109 | *> elementary reflector H(i), for i = 1,2,...,k, as returned by |
---|
110 | *> STZRZF in the last k rows of its array argument A. |
---|
111 | *> A is modified by the routine but restored on exit. |
---|
112 | *> \endverbatim |
---|
113 | *> |
---|
114 | *> \param[in] LDA |
---|
115 | *> \verbatim |
---|
116 | *> LDA is INTEGER |
---|
117 | *> The leading dimension of the array A. LDA >= max(1,K). |
---|
118 | *> \endverbatim |
---|
119 | *> |
---|
120 | *> \param[in] TAU |
---|
121 | *> \verbatim |
---|
122 | *> TAU is REAL array, dimension (K) |
---|
123 | *> TAU(i) must contain the scalar factor of the elementary |
---|
124 | *> reflector H(i), as returned by STZRZF. |
---|
125 | *> \endverbatim |
---|
126 | *> |
---|
127 | *> \param[in,out] C |
---|
128 | *> \verbatim |
---|
129 | *> C is REAL array, dimension (LDC,N) |
---|
130 | *> On entry, the m-by-n matrix C. |
---|
131 | *> On exit, C is overwritten by Q*C or Q**T*C or C*Q**T or C*Q. |
---|
132 | *> \endverbatim |
---|
133 | *> |
---|
134 | *> \param[in] LDC |
---|
135 | *> \verbatim |
---|
136 | *> LDC is INTEGER |
---|
137 | *> The leading dimension of the array C. LDC >= max(1,M). |
---|
138 | *> \endverbatim |
---|
139 | *> |
---|
140 | *> \param[out] WORK |
---|
141 | *> \verbatim |
---|
142 | *> WORK is REAL array, dimension |
---|
143 | *> (N) if SIDE = 'L', |
---|
144 | *> (M) if SIDE = 'R' |
---|
145 | *> \endverbatim |
---|
146 | *> |
---|
147 | *> \param[out] INFO |
---|
148 | *> \verbatim |
---|
149 | *> INFO is INTEGER |
---|
150 | *> = 0: successful exit |
---|
151 | *> < 0: if INFO = -i, the i-th argument had an illegal value |
---|
152 | *> \endverbatim |
---|
153 | * |
---|
154 | * Authors: |
---|
155 | * ======== |
---|
156 | * |
---|
157 | *> \author Univ. of Tennessee |
---|
158 | *> \author Univ. of California Berkeley |
---|
159 | *> \author Univ. of Colorado Denver |
---|
160 | *> \author NAG Ltd. |
---|
161 | * |
---|
162 | *> \date November 2011 |
---|
163 | * |
---|
164 | *> \ingroup realOTHERcomputational |
---|
165 | * |
---|
166 | *> \par Contributors: |
---|
167 | * ================== |
---|
168 | *> |
---|
169 | *> A. Petitet, Computer Science Dept., Univ. of Tenn., Knoxville, USA |
---|
170 | * |
---|
171 | *> \par Further Details: |
---|
172 | * ===================== |
---|
173 | *> |
---|
174 | *> \verbatim |
---|
175 | *> \endverbatim |
---|
176 | *> |
---|
177 | * ===================================================================== |
---|
178 | SUBROUTINE SORMR3( SIDE, TRANS, M, N, K, L, A, LDA, TAU, C, LDC, |
---|
179 | $ WORK, INFO ) |
---|
180 | * |
---|
181 | * -- LAPACK computational routine (version 3.4.0) -- |
---|
182 | * -- LAPACK is a software package provided by Univ. of Tennessee, -- |
---|
183 | * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- |
---|
184 | * November 2011 |
---|
185 | * |
---|
186 | * .. Scalar Arguments .. |
---|
187 | CHARACTER SIDE, TRANS |
---|
188 | INTEGER INFO, K, L, LDA, LDC, M, N |
---|
189 | * .. |
---|
190 | * .. Array Arguments .. |
---|
191 | REAL A( LDA, * ), C( LDC, * ), TAU( * ), WORK( * ) |
---|
192 | * .. |
---|
193 | * |
---|
194 | * ===================================================================== |
---|
195 | * |
---|
196 | * .. Local Scalars .. |
---|
197 | LOGICAL LEFT, NOTRAN |
---|
198 | INTEGER I, I1, I2, I3, IC, JA, JC, MI, NI, NQ |
---|
199 | * .. |
---|
200 | * .. External Functions .. |
---|
201 | LOGICAL LSAME |
---|
202 | EXTERNAL LSAME |
---|
203 | * .. |
---|
204 | * .. External Subroutines .. |
---|
205 | EXTERNAL SLARZ, XERBLA |
---|
206 | * .. |
---|
207 | * .. Intrinsic Functions .. |
---|
208 | INTRINSIC MAX |
---|
209 | * .. |
---|
210 | * .. Executable Statements .. |
---|
211 | * |
---|
212 | * Test the input arguments |
---|
213 | * |
---|
214 | INFO = 0 |
---|
215 | LEFT = LSAME( SIDE, 'L' ) |
---|
216 | NOTRAN = LSAME( TRANS, 'N' ) |
---|
217 | * |
---|
218 | * NQ is the order of Q |
---|
219 | * |
---|
220 | IF( LEFT ) THEN |
---|
221 | NQ = M |
---|
222 | ELSE |
---|
223 | NQ = N |
---|
224 | END IF |
---|
225 | IF( .NOT.LEFT .AND. .NOT.LSAME( SIDE, 'R' ) ) THEN |
---|
226 | INFO = -1 |
---|
227 | ELSE IF( .NOT.NOTRAN .AND. .NOT.LSAME( TRANS, 'T' ) ) THEN |
---|
228 | INFO = -2 |
---|
229 | ELSE IF( M.LT.0 ) THEN |
---|
230 | INFO = -3 |
---|
231 | ELSE IF( N.LT.0 ) THEN |
---|
232 | INFO = -4 |
---|
233 | ELSE IF( K.LT.0 .OR. K.GT.NQ ) THEN |
---|
234 | INFO = -5 |
---|
235 | ELSE IF( L.LT.0 .OR. ( LEFT .AND. ( L.GT.M ) ) .OR. |
---|
236 | $ ( .NOT.LEFT .AND. ( L.GT.N ) ) ) THEN |
---|
237 | INFO = -6 |
---|
238 | ELSE IF( LDA.LT.MAX( 1, K ) ) THEN |
---|
239 | INFO = -8 |
---|
240 | ELSE IF( LDC.LT.MAX( 1, M ) ) THEN |
---|
241 | INFO = -11 |
---|
242 | END IF |
---|
243 | IF( INFO.NE.0 ) THEN |
---|
244 | CALL XERBLA( 'SORMR3', -INFO ) |
---|
245 | RETURN |
---|
246 | END IF |
---|
247 | * |
---|
248 | * Quick return if possible |
---|
249 | * |
---|
250 | IF( M.EQ.0 .OR. N.EQ.0 .OR. K.EQ.0 ) |
---|
251 | $ RETURN |
---|
252 | * |
---|
253 | IF( ( LEFT .AND. .NOT.NOTRAN .OR. .NOT.LEFT .AND. NOTRAN ) ) THEN |
---|
254 | I1 = 1 |
---|
255 | I2 = K |
---|
256 | I3 = 1 |
---|
257 | ELSE |
---|
258 | I1 = K |
---|
259 | I2 = 1 |
---|
260 | I3 = -1 |
---|
261 | END IF |
---|
262 | * |
---|
263 | IF( LEFT ) THEN |
---|
264 | NI = N |
---|
265 | JA = M - L + 1 |
---|
266 | JC = 1 |
---|
267 | ELSE |
---|
268 | MI = M |
---|
269 | JA = N - L + 1 |
---|
270 | IC = 1 |
---|
271 | END IF |
---|
272 | * |
---|
273 | DO 10 I = I1, I2, I3 |
---|
274 | IF( LEFT ) THEN |
---|
275 | * |
---|
276 | * H(i) or H(i)**T is applied to C(i:m,1:n) |
---|
277 | * |
---|
278 | MI = M - I + 1 |
---|
279 | IC = I |
---|
280 | ELSE |
---|
281 | * |
---|
282 | * H(i) or H(i)**T is applied to C(1:m,i:n) |
---|
283 | * |
---|
284 | NI = N - I + 1 |
---|
285 | JC = I |
---|
286 | END IF |
---|
287 | * |
---|
288 | * Apply H(i) or H(i)**T |
---|
289 | * |
---|
290 | CALL SLARZ( SIDE, MI, NI, L, A( I, JA ), LDA, TAU( I ), |
---|
291 | $ C( IC, JC ), LDC, WORK ) |
---|
292 | * |
---|
293 | 10 CONTINUE |
---|
294 | * |
---|
295 | RETURN |
---|
296 | * |
---|
297 | * End of SORMR3 |
---|
298 | * |
---|
299 | END |
---|