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Mise à jour de lapack vers la version 3.3.0.
1: SUBROUTINE ZUNGL2( M, N, K, A, LDA, TAU, WORK, INFO ) 2: * 3: * -- LAPACK routine (version 3.2) -- 4: * -- LAPACK is a software package provided by Univ. of Tennessee, -- 5: * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- 6: * November 2006 7: * 8: * .. Scalar Arguments .. 9: INTEGER INFO, K, LDA, M, N 10: * .. 11: * .. Array Arguments .. 12: COMPLEX*16 A( LDA, * ), TAU( * ), WORK( * ) 13: * .. 14: * 15: * Purpose 16: * ======= 17: * 18: * ZUNGL2 generates an m-by-n complex matrix Q with orthonormal rows, 19: * which is defined as the first m rows of a product of k elementary 20: * reflectors of order n 21: * 22: * Q = H(k)' . . . H(2)' H(1)' 23: * 24: * as returned by ZGELQF. 25: * 26: * Arguments 27: * ========= 28: * 29: * M (input) INTEGER 30: * The number of rows of the matrix Q. M >= 0. 31: * 32: * N (input) INTEGER 33: * The number of columns of the matrix Q. N >= M. 34: * 35: * K (input) INTEGER 36: * The number of elementary reflectors whose product defines the 37: * matrix Q. M >= K >= 0. 38: * 39: * A (input/output) COMPLEX*16 array, dimension (LDA,N) 40: * On entry, the i-th row must contain the vector which defines 41: * the elementary reflector H(i), for i = 1,2,...,k, as returned 42: * by ZGELQF in the first k rows of its array argument A. 43: * On exit, the m by n matrix Q. 44: * 45: * LDA (input) INTEGER 46: * The first dimension of the array A. LDA >= max(1,M). 47: * 48: * TAU (input) COMPLEX*16 array, dimension (K) 49: * TAU(i) must contain the scalar factor of the elementary 50: * reflector H(i), as returned by ZGELQF. 51: * 52: * WORK (workspace) COMPLEX*16 array, dimension (M) 53: * 54: * INFO (output) INTEGER 55: * = 0: successful exit 56: * < 0: if INFO = -i, the i-th argument has an illegal value 57: * 58: * ===================================================================== 59: * 60: * .. Parameters .. 61: COMPLEX*16 ONE, ZERO 62: PARAMETER ( ONE = ( 1.0D+0, 0.0D+0 ), 63: $ ZERO = ( 0.0D+0, 0.0D+0 ) ) 64: * .. 65: * .. Local Scalars .. 66: INTEGER I, J, L 67: * .. 68: * .. External Subroutines .. 69: EXTERNAL XERBLA, ZLACGV, ZLARF, ZSCAL 70: * .. 71: * .. Intrinsic Functions .. 72: INTRINSIC DCONJG, MAX 73: * .. 74: * .. Executable Statements .. 75: * 76: * Test the input arguments 77: * 78: INFO = 0 79: IF( M.LT.0 ) THEN 80: INFO = -1 81: ELSE IF( N.LT.M ) THEN 82: INFO = -2 83: ELSE IF( K.LT.0 .OR. K.GT.M ) THEN 84: INFO = -3 85: ELSE IF( LDA.LT.MAX( 1, M ) ) THEN 86: INFO = -5 87: END IF 88: IF( INFO.NE.0 ) THEN 89: CALL XERBLA( 'ZUNGL2', -INFO ) 90: RETURN 91: END IF 92: * 93: * Quick return if possible 94: * 95: IF( M.LE.0 ) 96: $ RETURN 97: * 98: IF( K.LT.M ) THEN 99: * 100: * Initialise rows k+1:m to rows of the unit matrix 101: * 102: DO 20 J = 1, N 103: DO 10 L = K + 1, M 104: A( L, J ) = ZERO 105: 10 CONTINUE 106: IF( J.GT.K .AND. J.LE.M ) 107: $ A( J, J ) = ONE 108: 20 CONTINUE 109: END IF 110: * 111: DO 40 I = K, 1, -1 112: * 113: * Apply H(i)' to A(i:m,i:n) from the right 114: * 115: IF( I.LT.N ) THEN 116: CALL ZLACGV( N-I, A( I, I+1 ), LDA ) 117: IF( I.LT.M ) THEN 118: A( I, I ) = ONE 119: CALL ZLARF( 'Right', M-I, N-I+1, A( I, I ), LDA, 120: $ DCONJG( TAU( I ) ), A( I+1, I ), LDA, WORK ) 121: END IF 122: CALL ZSCAL( N-I, -TAU( I ), A( I, I+1 ), LDA ) 123: CALL ZLACGV( N-I, A( I, I+1 ), LDA ) 124: END IF 125: A( I, I ) = ONE - DCONJG( TAU( I ) ) 126: * 127: * Set A(i,1:i-1) to zero 128: * 129: DO 30 L = 1, I - 1 130: A( I, L ) = ZERO 131: 30 CONTINUE 132: 40 CONTINUE 133: RETURN 134: * 135: * End of ZUNGL2 136: * 137: END