Annotation of rpl/lapack/lapack/zunmtr.f, revision 1.8
1.8 ! bertrand 1: *> \brief \b ZUNMTR
! 2: *
! 3: * =========== DOCUMENTATION ===========
! 4: *
! 5: * Online html documentation available at
! 6: * http://www.netlib.org/lapack/explore-html/
! 7: *
! 8: *> \htmlonly
! 9: *> Download ZUNMTR + dependencies
! 10: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/zunmtr.f">
! 11: *> [TGZ]</a>
! 12: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/zunmtr.f">
! 13: *> [ZIP]</a>
! 14: *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/zunmtr.f">
! 15: *> [TXT]</a>
! 16: *> \endhtmlonly
! 17: *
! 18: * Definition:
! 19: * ===========
! 20: *
! 21: * SUBROUTINE ZUNMTR( SIDE, UPLO, TRANS, M, N, A, LDA, TAU, C, LDC,
! 22: * WORK, LWORK, INFO )
! 23: *
! 24: * .. Scalar Arguments ..
! 25: * CHARACTER SIDE, TRANS, UPLO
! 26: * INTEGER INFO, LDA, LDC, LWORK, 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: *> ZUNMTR overwrites the general complex M-by-N matrix C with
! 39: *>
! 40: *> SIDE = 'L' SIDE = 'R'
! 41: *> TRANS = 'N': Q * C C * Q
! 42: *> TRANS = 'C': Q**H * C C * Q**H
! 43: *>
! 44: *> where Q is a complex unitary matrix of order nq, with nq = m if
! 45: *> SIDE = 'L' and nq = n if SIDE = 'R'. Q is defined as the product of
! 46: *> nq-1 elementary reflectors, as returned by ZHETRD:
! 47: *>
! 48: *> if UPLO = 'U', Q = H(nq-1) . . . H(2) H(1);
! 49: *>
! 50: *> if UPLO = 'L', Q = H(1) H(2) . . . H(nq-1).
! 51: *> \endverbatim
! 52: *
! 53: * Arguments:
! 54: * ==========
! 55: *
! 56: *> \param[in] SIDE
! 57: *> \verbatim
! 58: *> SIDE is CHARACTER*1
! 59: *> = 'L': apply Q or Q**H from the Left;
! 60: *> = 'R': apply Q or Q**H from the Right.
! 61: *> \endverbatim
! 62: *>
! 63: *> \param[in] UPLO
! 64: *> \verbatim
! 65: *> UPLO is CHARACTER*1
! 66: *> = 'U': Upper triangle of A contains elementary reflectors
! 67: *> from ZHETRD;
! 68: *> = 'L': Lower triangle of A contains elementary reflectors
! 69: *> from ZHETRD.
! 70: *> \endverbatim
! 71: *>
! 72: *> \param[in] TRANS
! 73: *> \verbatim
! 74: *> TRANS is CHARACTER*1
! 75: *> = 'N': No transpose, apply Q;
! 76: *> = 'C': Conjugate transpose, apply Q**H.
! 77: *> \endverbatim
! 78: *>
! 79: *> \param[in] M
! 80: *> \verbatim
! 81: *> M is INTEGER
! 82: *> The number of rows of the matrix C. M >= 0.
! 83: *> \endverbatim
! 84: *>
! 85: *> \param[in] N
! 86: *> \verbatim
! 87: *> N is INTEGER
! 88: *> The number of columns of the matrix C. N >= 0.
! 89: *> \endverbatim
! 90: *>
! 91: *> \param[in] A
! 92: *> \verbatim
! 93: *> A is COMPLEX*16 array, dimension
! 94: *> (LDA,M) if SIDE = 'L'
! 95: *> (LDA,N) if SIDE = 'R'
! 96: *> The vectors which define the elementary reflectors, as
! 97: *> returned by ZHETRD.
! 98: *> \endverbatim
! 99: *>
! 100: *> \param[in] LDA
! 101: *> \verbatim
! 102: *> LDA is INTEGER
! 103: *> The leading dimension of the array A.
! 104: *> LDA >= max(1,M) if SIDE = 'L'; LDA >= max(1,N) if SIDE = 'R'.
! 105: *> \endverbatim
! 106: *>
! 107: *> \param[in] TAU
! 108: *> \verbatim
! 109: *> TAU is COMPLEX*16 array, dimension
! 110: *> (M-1) if SIDE = 'L'
! 111: *> (N-1) if SIDE = 'R'
! 112: *> TAU(i) must contain the scalar factor of the elementary
! 113: *> reflector H(i), as returned by ZHETRD.
! 114: *> \endverbatim
! 115: *>
! 116: *> \param[in,out] C
! 117: *> \verbatim
! 118: *> C is COMPLEX*16 array, dimension (LDC,N)
! 119: *> On entry, the M-by-N matrix C.
! 120: *> On exit, C is overwritten by Q*C or Q**H*C or C*Q**H or C*Q.
! 121: *> \endverbatim
! 122: *>
! 123: *> \param[in] LDC
! 124: *> \verbatim
! 125: *> LDC is INTEGER
! 126: *> The leading dimension of the array C. LDC >= max(1,M).
! 127: *> \endverbatim
! 128: *>
! 129: *> \param[out] WORK
! 130: *> \verbatim
! 131: *> WORK is COMPLEX*16 array, dimension (MAX(1,LWORK))
! 132: *> On exit, if INFO = 0, WORK(1) returns the optimal LWORK.
! 133: *> \endverbatim
! 134: *>
! 135: *> \param[in] LWORK
! 136: *> \verbatim
! 137: *> LWORK is INTEGER
! 138: *> The dimension of the array WORK.
! 139: *> If SIDE = 'L', LWORK >= max(1,N);
! 140: *> if SIDE = 'R', LWORK >= max(1,M).
! 141: *> For optimum performance LWORK >= N*NB if SIDE = 'L', and
! 142: *> LWORK >=M*NB if SIDE = 'R', where NB is the optimal
! 143: *> blocksize.
! 144: *>
! 145: *> If LWORK = -1, then a workspace query is assumed; the routine
! 146: *> only calculates the optimal size of the WORK array, returns
! 147: *> this value as the first entry of the WORK array, and no error
! 148: *> message related to LWORK is issued by XERBLA.
! 149: *> \endverbatim
! 150: *>
! 151: *> \param[out] INFO
! 152: *> \verbatim
! 153: *> INFO is INTEGER
! 154: *> = 0: successful exit
! 155: *> < 0: if INFO = -i, the i-th argument had an illegal value
! 156: *> \endverbatim
! 157: *
! 158: * Authors:
! 159: * ========
! 160: *
! 161: *> \author Univ. of Tennessee
! 162: *> \author Univ. of California Berkeley
! 163: *> \author Univ. of Colorado Denver
! 164: *> \author NAG Ltd.
! 165: *
! 166: *> \date November 2011
! 167: *
! 168: *> \ingroup complex16OTHERcomputational
! 169: *
! 170: * =====================================================================
1.1 bertrand 171: SUBROUTINE ZUNMTR( SIDE, UPLO, TRANS, M, N, A, LDA, TAU, C, LDC,
172: $ WORK, LWORK, INFO )
173: *
1.8 ! bertrand 174: * -- LAPACK computational routine (version 3.4.0) --
1.1 bertrand 175: * -- LAPACK is a software package provided by Univ. of Tennessee, --
176: * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
1.8 ! bertrand 177: * November 2011
1.1 bertrand 178: *
179: * .. Scalar Arguments ..
180: CHARACTER SIDE, TRANS, UPLO
181: INTEGER INFO, LDA, LDC, LWORK, M, N
182: * ..
183: * .. Array Arguments ..
184: COMPLEX*16 A( LDA, * ), C( LDC, * ), TAU( * ), WORK( * )
185: * ..
186: *
187: * =====================================================================
188: *
189: * .. Local Scalars ..
190: LOGICAL LEFT, LQUERY, UPPER
191: INTEGER I1, I2, IINFO, LWKOPT, MI, NB, NI, NQ, NW
192: * ..
193: * .. External Functions ..
194: LOGICAL LSAME
195: INTEGER ILAENV
196: EXTERNAL LSAME, ILAENV
197: * ..
198: * .. External Subroutines ..
199: EXTERNAL XERBLA, ZUNMQL, ZUNMQR
200: * ..
201: * .. Intrinsic Functions ..
202: INTRINSIC MAX
203: * ..
204: * .. Executable Statements ..
205: *
206: * Test the input arguments
207: *
208: INFO = 0
209: LEFT = LSAME( SIDE, 'L' )
210: UPPER = LSAME( UPLO, 'U' )
211: LQUERY = ( LWORK.EQ.-1 )
212: *
213: * NQ is the order of Q and NW is the minimum dimension of WORK
214: *
215: IF( LEFT ) THEN
216: NQ = M
217: NW = N
218: ELSE
219: NQ = N
220: NW = M
221: END IF
222: IF( .NOT.LEFT .AND. .NOT.LSAME( SIDE, 'R' ) ) THEN
223: INFO = -1
224: ELSE IF( .NOT.UPPER .AND. .NOT.LSAME( UPLO, 'L' ) ) THEN
225: INFO = -2
226: ELSE IF( .NOT.LSAME( TRANS, 'N' ) .AND. .NOT.LSAME( TRANS, 'C' ) )
227: $ THEN
228: INFO = -3
229: ELSE IF( M.LT.0 ) THEN
230: INFO = -4
231: ELSE IF( N.LT.0 ) THEN
232: INFO = -5
233: ELSE IF( LDA.LT.MAX( 1, NQ ) ) THEN
234: INFO = -7
235: ELSE IF( LDC.LT.MAX( 1, M ) ) THEN
236: INFO = -10
237: ELSE IF( LWORK.LT.MAX( 1, NW ) .AND. .NOT.LQUERY ) THEN
238: INFO = -12
239: END IF
240: *
241: IF( INFO.EQ.0 ) THEN
242: IF( UPPER ) THEN
243: IF( LEFT ) THEN
244: NB = ILAENV( 1, 'ZUNMQL', SIDE // TRANS, M-1, N, M-1,
245: $ -1 )
246: ELSE
247: NB = ILAENV( 1, 'ZUNMQL', SIDE // TRANS, M, N-1, N-1,
248: $ -1 )
249: END IF
250: ELSE
251: IF( LEFT ) THEN
252: NB = ILAENV( 1, 'ZUNMQR', SIDE // TRANS, M-1, N, M-1,
253: $ -1 )
254: ELSE
255: NB = ILAENV( 1, 'ZUNMQR', SIDE // TRANS, M, N-1, N-1,
256: $ -1 )
257: END IF
258: END IF
259: LWKOPT = MAX( 1, NW )*NB
260: WORK( 1 ) = LWKOPT
261: END IF
262: *
263: IF( INFO.NE.0 ) THEN
264: CALL XERBLA( 'ZUNMTR', -INFO )
265: RETURN
266: ELSE IF( LQUERY ) THEN
267: RETURN
268: END IF
269: *
270: * Quick return if possible
271: *
272: IF( M.EQ.0 .OR. N.EQ.0 .OR. NQ.EQ.1 ) THEN
273: WORK( 1 ) = 1
274: RETURN
275: END IF
276: *
277: IF( LEFT ) THEN
278: MI = M - 1
279: NI = N
280: ELSE
281: MI = M
282: NI = N - 1
283: END IF
284: *
285: IF( UPPER ) THEN
286: *
287: * Q was determined by a call to ZHETRD with UPLO = 'U'
288: *
289: CALL ZUNMQL( SIDE, TRANS, MI, NI, NQ-1, A( 1, 2 ), LDA, TAU, C,
290: $ LDC, WORK, LWORK, IINFO )
291: ELSE
292: *
293: * Q was determined by a call to ZHETRD with UPLO = 'L'
294: *
295: IF( LEFT ) THEN
296: I1 = 2
297: I2 = 1
298: ELSE
299: I1 = 1
300: I2 = 2
301: END IF
302: CALL ZUNMQR( SIDE, TRANS, MI, NI, NQ-1, A( 2, 1 ), LDA, TAU,
303: $ C( I1, I2 ), LDC, WORK, LWORK, IINFO )
304: END IF
305: WORK( 1 ) = LWKOPT
306: RETURN
307: *
308: * End of ZUNMTR
309: *
310: END
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