Annotation of rpl/lapack/lapack/zunmr3.f, revision 1.9
1.9 ! bertrand 1: *> \brief \b ZUNMR3
! 2: *
! 3: * =========== DOCUMENTATION ===========
! 4: *
! 5: * Online html documentation available at
! 6: * http://www.netlib.org/lapack/explore-html/
! 7: *
! 8: *> \htmlonly
! 9: *> Download ZUNMR3 + dependencies
! 10: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/zunmr3.f">
! 11: *> [TGZ]</a>
! 12: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/zunmr3.f">
! 13: *> [ZIP]</a>
! 14: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/zunmr3.f">
! 15: *> [TXT]</a>
! 16: *> \endhtmlonly
! 17: *
! 18: * Definition:
! 19: * ===========
! 20: *
! 21: * SUBROUTINE ZUNMR3( 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: * COMPLEX*16 A( LDA, * ), C( LDC, * ), TAU( * ), WORK( * )
! 30: * ..
! 31: *
! 32: *
! 33: *> \par Purpose:
! 34: * =============
! 35: *>
! 36: *> \verbatim
! 37: *>
! 38: *> ZUNMR3 overwrites the general complex m by n matrix C with
! 39: *>
! 40: *> Q * C if SIDE = 'L' and TRANS = 'N', or
! 41: *>
! 42: *> Q**H* C if SIDE = 'L' and TRANS = 'C', or
! 43: *>
! 44: *> C * Q if SIDE = 'R' and TRANS = 'N', or
! 45: *>
! 46: *> C * Q**H if SIDE = 'R' and TRANS = 'C',
! 47: *>
! 48: *> where Q is a complex unitary matrix defined as the product of k
! 49: *> elementary reflectors
! 50: *>
! 51: *> Q = H(1) H(2) . . . H(k)
! 52: *>
! 53: *> as returned by ZTZRZF. 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**H from the Left
! 64: *> = 'R': apply Q or Q**H from the Right
! 65: *> \endverbatim
! 66: *>
! 67: *> \param[in] TRANS
! 68: *> \verbatim
! 69: *> TRANS is CHARACTER*1
! 70: *> = 'N': apply Q (No transpose)
! 71: *> = 'C': apply Q**H (Conjugate 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 COMPLEX*16 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: *> ZTZRZF 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 COMPLEX*16 array, dimension (K)
! 123: *> TAU(i) must contain the scalar factor of the elementary
! 124: *> reflector H(i), as returned by ZTZRZF.
! 125: *> \endverbatim
! 126: *>
! 127: *> \param[in,out] C
! 128: *> \verbatim
! 129: *> C is COMPLEX*16 array, dimension (LDC,N)
! 130: *> On entry, the m-by-n matrix C.
! 131: *> On exit, C is overwritten by Q*C or Q**H*C or C*Q**H 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 COMPLEX*16 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 complex16OTHERcomputational
! 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: * =====================================================================
1.1 bertrand 178: SUBROUTINE ZUNMR3( SIDE, TRANS, M, N, K, L, A, LDA, TAU, C, LDC,
179: $ WORK, INFO )
180: *
1.9 ! bertrand 181: * -- LAPACK computational routine (version 3.4.0) --
1.1 bertrand 182: * -- LAPACK is a software package provided by Univ. of Tennessee, --
183: * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
1.9 ! bertrand 184: * November 2011
1.1 bertrand 185: *
186: * .. Scalar Arguments ..
187: CHARACTER SIDE, TRANS
188: INTEGER INFO, K, L, LDA, LDC, M, N
189: * ..
190: * .. Array Arguments ..
191: COMPLEX*16 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: COMPLEX*16 TAUI
200: * ..
201: * .. External Functions ..
202: LOGICAL LSAME
203: EXTERNAL LSAME
204: * ..
205: * .. External Subroutines ..
206: EXTERNAL XERBLA, ZLARZ
207: * ..
208: * .. Intrinsic Functions ..
209: INTRINSIC DCONJG, MAX
210: * ..
211: * .. Executable Statements ..
212: *
213: * Test the input arguments
214: *
215: INFO = 0
216: LEFT = LSAME( SIDE, 'L' )
217: NOTRAN = LSAME( TRANS, 'N' )
218: *
219: * NQ is the order of Q
220: *
221: IF( LEFT ) THEN
222: NQ = M
223: ELSE
224: NQ = N
225: END IF
226: IF( .NOT.LEFT .AND. .NOT.LSAME( SIDE, 'R' ) ) THEN
227: INFO = -1
228: ELSE IF( .NOT.NOTRAN .AND. .NOT.LSAME( TRANS, 'C' ) ) THEN
229: INFO = -2
230: ELSE IF( M.LT.0 ) THEN
231: INFO = -3
232: ELSE IF( N.LT.0 ) THEN
233: INFO = -4
234: ELSE IF( K.LT.0 .OR. K.GT.NQ ) THEN
235: INFO = -5
236: ELSE IF( L.LT.0 .OR. ( LEFT .AND. ( L.GT.M ) ) .OR.
237: $ ( .NOT.LEFT .AND. ( L.GT.N ) ) ) THEN
238: INFO = -6
239: ELSE IF( LDA.LT.MAX( 1, K ) ) THEN
240: INFO = -8
241: ELSE IF( LDC.LT.MAX( 1, M ) ) THEN
242: INFO = -11
243: END IF
244: IF( INFO.NE.0 ) THEN
245: CALL XERBLA( 'ZUNMR3', -INFO )
246: RETURN
247: END IF
248: *
249: * Quick return if possible
250: *
251: IF( M.EQ.0 .OR. N.EQ.0 .OR. K.EQ.0 )
252: $ RETURN
253: *
254: IF( ( LEFT .AND. .NOT.NOTRAN .OR. .NOT.LEFT .AND. NOTRAN ) ) THEN
255: I1 = 1
256: I2 = K
257: I3 = 1
258: ELSE
259: I1 = K
260: I2 = 1
261: I3 = -1
262: END IF
263: *
264: IF( LEFT ) THEN
265: NI = N
266: JA = M - L + 1
267: JC = 1
268: ELSE
269: MI = M
270: JA = N - L + 1
271: IC = 1
272: END IF
273: *
274: DO 10 I = I1, I2, I3
275: IF( LEFT ) THEN
276: *
1.8 bertrand 277: * H(i) or H(i)**H is applied to C(i:m,1:n)
1.1 bertrand 278: *
279: MI = M - I + 1
280: IC = I
281: ELSE
282: *
1.8 bertrand 283: * H(i) or H(i)**H is applied to C(1:m,i:n)
1.1 bertrand 284: *
285: NI = N - I + 1
286: JC = I
287: END IF
288: *
1.8 bertrand 289: * Apply H(i) or H(i)**H
1.1 bertrand 290: *
291: IF( NOTRAN ) THEN
292: TAUI = TAU( I )
293: ELSE
294: TAUI = DCONJG( TAU( I ) )
295: END IF
296: CALL ZLARZ( SIDE, MI, NI, L, A( I, JA ), LDA, TAUI,
297: $ C( IC, JC ), LDC, WORK )
298: *
299: 10 CONTINUE
300: *
301: RETURN
302: *
303: * End of ZUNMR3
304: *
305: END
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