Annotation of rpl/lapack/lapack/zunmtr.f, revision 1.1
1.1 ! bertrand 1: SUBROUTINE ZUNMTR( SIDE, UPLO, TRANS, M, N, A, LDA, TAU, C, LDC,
! 2: $ WORK, LWORK, INFO )
! 3: *
! 4: * -- LAPACK routine (version 3.2) --
! 5: * -- LAPACK is a software package provided by Univ. of Tennessee, --
! 6: * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
! 7: * November 2006
! 8: *
! 9: * .. Scalar Arguments ..
! 10: CHARACTER SIDE, TRANS, UPLO
! 11: INTEGER INFO, LDA, LDC, LWORK, M, N
! 12: * ..
! 13: * .. Array Arguments ..
! 14: COMPLEX*16 A( LDA, * ), C( LDC, * ), TAU( * ), WORK( * )
! 15: * ..
! 16: *
! 17: * Purpose
! 18: * =======
! 19: *
! 20: * ZUNMTR overwrites the general complex M-by-N matrix C with
! 21: *
! 22: * SIDE = 'L' SIDE = 'R'
! 23: * TRANS = 'N': Q * C C * Q
! 24: * TRANS = 'C': Q**H * C C * Q**H
! 25: *
! 26: * where Q is a complex unitary matrix of order nq, with nq = m if
! 27: * SIDE = 'L' and nq = n if SIDE = 'R'. Q is defined as the product of
! 28: * nq-1 elementary reflectors, as returned by ZHETRD:
! 29: *
! 30: * if UPLO = 'U', Q = H(nq-1) . . . H(2) H(1);
! 31: *
! 32: * if UPLO = 'L', Q = H(1) H(2) . . . H(nq-1).
! 33: *
! 34: * Arguments
! 35: * =========
! 36: *
! 37: * SIDE (input) CHARACTER*1
! 38: * = 'L': apply Q or Q**H from the Left;
! 39: * = 'R': apply Q or Q**H from the Right.
! 40: *
! 41: * UPLO (input) CHARACTER*1
! 42: * = 'U': Upper triangle of A contains elementary reflectors
! 43: * from ZHETRD;
! 44: * = 'L': Lower triangle of A contains elementary reflectors
! 45: * from ZHETRD.
! 46: *
! 47: * TRANS (input) CHARACTER*1
! 48: * = 'N': No transpose, apply Q;
! 49: * = 'C': Conjugate transpose, apply Q**H.
! 50: *
! 51: * M (input) INTEGER
! 52: * The number of rows of the matrix C. M >= 0.
! 53: *
! 54: * N (input) INTEGER
! 55: * The number of columns of the matrix C. N >= 0.
! 56: *
! 57: * A (input) COMPLEX*16 array, dimension
! 58: * (LDA,M) if SIDE = 'L'
! 59: * (LDA,N) if SIDE = 'R'
! 60: * The vectors which define the elementary reflectors, as
! 61: * returned by ZHETRD.
! 62: *
! 63: * LDA (input) INTEGER
! 64: * The leading dimension of the array A.
! 65: * LDA >= max(1,M) if SIDE = 'L'; LDA >= max(1,N) if SIDE = 'R'.
! 66: *
! 67: * TAU (input) COMPLEX*16 array, dimension
! 68: * (M-1) if SIDE = 'L'
! 69: * (N-1) if SIDE = 'R'
! 70: * TAU(i) must contain the scalar factor of the elementary
! 71: * reflector H(i), as returned by ZHETRD.
! 72: *
! 73: * C (input/output) COMPLEX*16 array, dimension (LDC,N)
! 74: * On entry, the M-by-N matrix C.
! 75: * On exit, C is overwritten by Q*C or Q**H*C or C*Q**H or C*Q.
! 76: *
! 77: * LDC (input) INTEGER
! 78: * The leading dimension of the array C. LDC >= max(1,M).
! 79: *
! 80: * WORK (workspace/output) COMPLEX*16 array, dimension (MAX(1,LWORK))
! 81: * On exit, if INFO = 0, WORK(1) returns the optimal LWORK.
! 82: *
! 83: * LWORK (input) INTEGER
! 84: * The dimension of the array WORK.
! 85: * If SIDE = 'L', LWORK >= max(1,N);
! 86: * if SIDE = 'R', LWORK >= max(1,M).
! 87: * For optimum performance LWORK >= N*NB if SIDE = 'L', and
! 88: * LWORK >=M*NB if SIDE = 'R', where NB is the optimal
! 89: * blocksize.
! 90: *
! 91: * If LWORK = -1, then a workspace query is assumed; the routine
! 92: * only calculates the optimal size of the WORK array, returns
! 93: * this value as the first entry of the WORK array, and no error
! 94: * message related to LWORK is issued by XERBLA.
! 95: *
! 96: * INFO (output) INTEGER
! 97: * = 0: successful exit
! 98: * < 0: if INFO = -i, the i-th argument had an illegal value
! 99: *
! 100: * =====================================================================
! 101: *
! 102: * .. Local Scalars ..
! 103: LOGICAL LEFT, LQUERY, UPPER
! 104: INTEGER I1, I2, IINFO, LWKOPT, MI, NB, NI, NQ, NW
! 105: * ..
! 106: * .. External Functions ..
! 107: LOGICAL LSAME
! 108: INTEGER ILAENV
! 109: EXTERNAL LSAME, ILAENV
! 110: * ..
! 111: * .. External Subroutines ..
! 112: EXTERNAL XERBLA, ZUNMQL, ZUNMQR
! 113: * ..
! 114: * .. Intrinsic Functions ..
! 115: INTRINSIC MAX
! 116: * ..
! 117: * .. Executable Statements ..
! 118: *
! 119: * Test the input arguments
! 120: *
! 121: INFO = 0
! 122: LEFT = LSAME( SIDE, 'L' )
! 123: UPPER = LSAME( UPLO, 'U' )
! 124: LQUERY = ( LWORK.EQ.-1 )
! 125: *
! 126: * NQ is the order of Q and NW is the minimum dimension of WORK
! 127: *
! 128: IF( LEFT ) THEN
! 129: NQ = M
! 130: NW = N
! 131: ELSE
! 132: NQ = N
! 133: NW = M
! 134: END IF
! 135: IF( .NOT.LEFT .AND. .NOT.LSAME( SIDE, 'R' ) ) THEN
! 136: INFO = -1
! 137: ELSE IF( .NOT.UPPER .AND. .NOT.LSAME( UPLO, 'L' ) ) THEN
! 138: INFO = -2
! 139: ELSE IF( .NOT.LSAME( TRANS, 'N' ) .AND. .NOT.LSAME( TRANS, 'C' ) )
! 140: $ THEN
! 141: INFO = -3
! 142: ELSE IF( M.LT.0 ) THEN
! 143: INFO = -4
! 144: ELSE IF( N.LT.0 ) THEN
! 145: INFO = -5
! 146: ELSE IF( LDA.LT.MAX( 1, NQ ) ) THEN
! 147: INFO = -7
! 148: ELSE IF( LDC.LT.MAX( 1, M ) ) THEN
! 149: INFO = -10
! 150: ELSE IF( LWORK.LT.MAX( 1, NW ) .AND. .NOT.LQUERY ) THEN
! 151: INFO = -12
! 152: END IF
! 153: *
! 154: IF( INFO.EQ.0 ) THEN
! 155: IF( UPPER ) THEN
! 156: IF( LEFT ) THEN
! 157: NB = ILAENV( 1, 'ZUNMQL', SIDE // TRANS, M-1, N, M-1,
! 158: $ -1 )
! 159: ELSE
! 160: NB = ILAENV( 1, 'ZUNMQL', SIDE // TRANS, M, N-1, N-1,
! 161: $ -1 )
! 162: END IF
! 163: ELSE
! 164: IF( LEFT ) THEN
! 165: NB = ILAENV( 1, 'ZUNMQR', SIDE // TRANS, M-1, N, M-1,
! 166: $ -1 )
! 167: ELSE
! 168: NB = ILAENV( 1, 'ZUNMQR', SIDE // TRANS, M, N-1, N-1,
! 169: $ -1 )
! 170: END IF
! 171: END IF
! 172: LWKOPT = MAX( 1, NW )*NB
! 173: WORK( 1 ) = LWKOPT
! 174: END IF
! 175: *
! 176: IF( INFO.NE.0 ) THEN
! 177: CALL XERBLA( 'ZUNMTR', -INFO )
! 178: RETURN
! 179: ELSE IF( LQUERY ) THEN
! 180: RETURN
! 181: END IF
! 182: *
! 183: * Quick return if possible
! 184: *
! 185: IF( M.EQ.0 .OR. N.EQ.0 .OR. NQ.EQ.1 ) THEN
! 186: WORK( 1 ) = 1
! 187: RETURN
! 188: END IF
! 189: *
! 190: IF( LEFT ) THEN
! 191: MI = M - 1
! 192: NI = N
! 193: ELSE
! 194: MI = M
! 195: NI = N - 1
! 196: END IF
! 197: *
! 198: IF( UPPER ) THEN
! 199: *
! 200: * Q was determined by a call to ZHETRD with UPLO = 'U'
! 201: *
! 202: CALL ZUNMQL( SIDE, TRANS, MI, NI, NQ-1, A( 1, 2 ), LDA, TAU, C,
! 203: $ LDC, WORK, LWORK, IINFO )
! 204: ELSE
! 205: *
! 206: * Q was determined by a call to ZHETRD with UPLO = 'L'
! 207: *
! 208: IF( LEFT ) THEN
! 209: I1 = 2
! 210: I2 = 1
! 211: ELSE
! 212: I1 = 1
! 213: I2 = 2
! 214: END IF
! 215: CALL ZUNMQR( SIDE, TRANS, MI, NI, NQ-1, A( 2, 1 ), LDA, TAU,
! 216: $ C( I1, I2 ), LDC, WORK, LWORK, IINFO )
! 217: END IF
! 218: WORK( 1 ) = LWKOPT
! 219: RETURN
! 220: *
! 221: * End of ZUNMTR
! 222: *
! 223: END
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