Annotation of rpl/lapack/lapack/zunmr3.f, revision 1.1
1.1 ! bertrand 1: SUBROUTINE ZUNMR3( SIDE, TRANS, M, N, K, L, A, LDA, TAU, C, LDC,
! 2: $ WORK, 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
! 11: INTEGER INFO, K, L, LDA, LDC, M, N
! 12: * ..
! 13: * .. Array Arguments ..
! 14: COMPLEX*16 A( LDA, * ), C( LDC, * ), TAU( * ), WORK( * )
! 15: * ..
! 16: *
! 17: * Purpose
! 18: * =======
! 19: *
! 20: * ZUNMR3 overwrites the general complex m by n matrix C with
! 21: *
! 22: * Q * C if SIDE = 'L' and TRANS = 'N', or
! 23: *
! 24: * Q'* C if SIDE = 'L' and TRANS = 'C', or
! 25: *
! 26: * C * Q if SIDE = 'R' and TRANS = 'N', or
! 27: *
! 28: * C * Q' if SIDE = 'R' and TRANS = 'C',
! 29: *
! 30: * where Q is a complex unitary matrix defined as the product of k
! 31: * elementary reflectors
! 32: *
! 33: * Q = H(1) H(2) . . . H(k)
! 34: *
! 35: * as returned by ZTZRZF. Q is of order m if SIDE = 'L' and of order n
! 36: * if SIDE = 'R'.
! 37: *
! 38: * Arguments
! 39: * =========
! 40: *
! 41: * SIDE (input) CHARACTER*1
! 42: * = 'L': apply Q or Q' from the Left
! 43: * = 'R': apply Q or Q' from the Right
! 44: *
! 45: * TRANS (input) CHARACTER*1
! 46: * = 'N': apply Q (No transpose)
! 47: * = 'C': apply Q' (Conjugate transpose)
! 48: *
! 49: * M (input) INTEGER
! 50: * The number of rows of the matrix C. M >= 0.
! 51: *
! 52: * N (input) INTEGER
! 53: * The number of columns of the matrix C. N >= 0.
! 54: *
! 55: * K (input) INTEGER
! 56: * The number of elementary reflectors whose product defines
! 57: * the matrix Q.
! 58: * If SIDE = 'L', M >= K >= 0;
! 59: * if SIDE = 'R', N >= K >= 0.
! 60: *
! 61: * L (input) INTEGER
! 62: * The number of columns of the matrix A containing
! 63: * the meaningful part of the Householder reflectors.
! 64: * If SIDE = 'L', M >= L >= 0, if SIDE = 'R', N >= L >= 0.
! 65: *
! 66: * A (input) COMPLEX*16 array, dimension
! 67: * (LDA,M) if SIDE = 'L',
! 68: * (LDA,N) if SIDE = 'R'
! 69: * The i-th row must contain the vector which defines the
! 70: * elementary reflector H(i), for i = 1,2,...,k, as returned by
! 71: * ZTZRZF in the last k rows of its array argument A.
! 72: * A is modified by the routine but restored on exit.
! 73: *
! 74: * LDA (input) INTEGER
! 75: * The leading dimension of the array A. LDA >= max(1,K).
! 76: *
! 77: * TAU (input) COMPLEX*16 array, dimension (K)
! 78: * TAU(i) must contain the scalar factor of the elementary
! 79: * reflector H(i), as returned by ZTZRZF.
! 80: *
! 81: * C (input/output) COMPLEX*16 array, dimension (LDC,N)
! 82: * On entry, the m-by-n matrix C.
! 83: * On exit, C is overwritten by Q*C or Q'*C or C*Q' or C*Q.
! 84: *
! 85: * LDC (input) INTEGER
! 86: * The leading dimension of the array C. LDC >= max(1,M).
! 87: *
! 88: * WORK (workspace) COMPLEX*16 array, dimension
! 89: * (N) if SIDE = 'L',
! 90: * (M) if SIDE = 'R'
! 91: *
! 92: * INFO (output) INTEGER
! 93: * = 0: successful exit
! 94: * < 0: if INFO = -i, the i-th argument had an illegal value
! 95: *
! 96: * Further Details
! 97: * ===============
! 98: *
! 99: * Based on contributions by
! 100: * A. Petitet, Computer Science Dept., Univ. of Tenn., Knoxville, USA
! 101: *
! 102: * =====================================================================
! 103: *
! 104: * .. Local Scalars ..
! 105: LOGICAL LEFT, NOTRAN
! 106: INTEGER I, I1, I2, I3, IC, JA, JC, MI, NI, NQ
! 107: COMPLEX*16 TAUI
! 108: * ..
! 109: * .. External Functions ..
! 110: LOGICAL LSAME
! 111: EXTERNAL LSAME
! 112: * ..
! 113: * .. External Subroutines ..
! 114: EXTERNAL XERBLA, ZLARZ
! 115: * ..
! 116: * .. Intrinsic Functions ..
! 117: INTRINSIC DCONJG, MAX
! 118: * ..
! 119: * .. Executable Statements ..
! 120: *
! 121: * Test the input arguments
! 122: *
! 123: INFO = 0
! 124: LEFT = LSAME( SIDE, 'L' )
! 125: NOTRAN = LSAME( TRANS, 'N' )
! 126: *
! 127: * NQ is the order of Q
! 128: *
! 129: IF( LEFT ) THEN
! 130: NQ = M
! 131: ELSE
! 132: NQ = N
! 133: END IF
! 134: IF( .NOT.LEFT .AND. .NOT.LSAME( SIDE, 'R' ) ) THEN
! 135: INFO = -1
! 136: ELSE IF( .NOT.NOTRAN .AND. .NOT.LSAME( TRANS, 'C' ) ) THEN
! 137: INFO = -2
! 138: ELSE IF( M.LT.0 ) THEN
! 139: INFO = -3
! 140: ELSE IF( N.LT.0 ) THEN
! 141: INFO = -4
! 142: ELSE IF( K.LT.0 .OR. K.GT.NQ ) THEN
! 143: INFO = -5
! 144: ELSE IF( L.LT.0 .OR. ( LEFT .AND. ( L.GT.M ) ) .OR.
! 145: $ ( .NOT.LEFT .AND. ( L.GT.N ) ) ) THEN
! 146: INFO = -6
! 147: ELSE IF( LDA.LT.MAX( 1, K ) ) THEN
! 148: INFO = -8
! 149: ELSE IF( LDC.LT.MAX( 1, M ) ) THEN
! 150: INFO = -11
! 151: END IF
! 152: IF( INFO.NE.0 ) THEN
! 153: CALL XERBLA( 'ZUNMR3', -INFO )
! 154: RETURN
! 155: END IF
! 156: *
! 157: * Quick return if possible
! 158: *
! 159: IF( M.EQ.0 .OR. N.EQ.0 .OR. K.EQ.0 )
! 160: $ RETURN
! 161: *
! 162: IF( ( LEFT .AND. .NOT.NOTRAN .OR. .NOT.LEFT .AND. NOTRAN ) ) THEN
! 163: I1 = 1
! 164: I2 = K
! 165: I3 = 1
! 166: ELSE
! 167: I1 = K
! 168: I2 = 1
! 169: I3 = -1
! 170: END IF
! 171: *
! 172: IF( LEFT ) THEN
! 173: NI = N
! 174: JA = M - L + 1
! 175: JC = 1
! 176: ELSE
! 177: MI = M
! 178: JA = N - L + 1
! 179: IC = 1
! 180: END IF
! 181: *
! 182: DO 10 I = I1, I2, I3
! 183: IF( LEFT ) THEN
! 184: *
! 185: * H(i) or H(i)' is applied to C(i:m,1:n)
! 186: *
! 187: MI = M - I + 1
! 188: IC = I
! 189: ELSE
! 190: *
! 191: * H(i) or H(i)' is applied to C(1:m,i:n)
! 192: *
! 193: NI = N - I + 1
! 194: JC = I
! 195: END IF
! 196: *
! 197: * Apply H(i) or H(i)'
! 198: *
! 199: IF( NOTRAN ) THEN
! 200: TAUI = TAU( I )
! 201: ELSE
! 202: TAUI = DCONJG( TAU( I ) )
! 203: END IF
! 204: CALL ZLARZ( SIDE, MI, NI, L, A( I, JA ), LDA, TAUI,
! 205: $ C( IC, JC ), LDC, WORK )
! 206: *
! 207: 10 CONTINUE
! 208: *
! 209: RETURN
! 210: *
! 211: * End of ZUNMR3
! 212: *
! 213: END
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