|
1
2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 |
SUBROUTINE SLATZM( SIDE, M, N, V, INCV, TAU, C1, C2, LDC, WORK )
* * -- LAPACK routine (version 3.3.1) -- * -- LAPACK is a software package provided by Univ. of Tennessee, -- * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- * -- April 2011 -- * * .. Scalar Arguments .. CHARACTER SIDE INTEGER INCV, LDC, M, N REAL TAU * .. * .. Array Arguments .. REAL C1( LDC, * ), C2( LDC, * ), V( * ), WORK( * ) * .. * * Purpose * ======= * * This routine is deprecated and has been replaced by routine SORMRZ. * * SLATZM applies a Householder matrix generated by STZRQF to a matrix. * * Let P = I - tau*u*u**T, u = ( 1 ), * ( v ) * where v is an (m-1) vector if SIDE = 'L', or a (n-1) vector if * SIDE = 'R'. * * If SIDE equals 'L', let * C = [ C1 ] 1 * [ C2 ] m-1 * n * Then C is overwritten by P*C. * * If SIDE equals 'R', let * C = [ C1, C2 ] m * 1 n-1 * Then C is overwritten by C*P. * * Arguments * ========= * * SIDE (input) CHARACTER*1 * = 'L': form P * C * = 'R': form C * P * * M (input) INTEGER * The number of rows of the matrix C. * * N (input) INTEGER * The number of columns of the matrix C. * * V (input) REAL array, dimension * (1 + (M-1)*abs(INCV)) if SIDE = 'L' * (1 + (N-1)*abs(INCV)) if SIDE = 'R' * The vector v in the representation of P. V is not used * if TAU = 0. * * INCV (input) INTEGER * The increment between elements of v. INCV <> 0 * * TAU (input) REAL * The value tau in the representation of P. * * C1 (input/output) REAL array, dimension * (LDC,N) if SIDE = 'L' * (M,1) if SIDE = 'R' * On entry, the n-vector C1 if SIDE = 'L', or the m-vector C1 * if SIDE = 'R'. * * On exit, the first row of P*C if SIDE = 'L', or the first * column of C*P if SIDE = 'R'. * * C2 (input/output) REAL array, dimension * (LDC, N) if SIDE = 'L' * (LDC, N-1) if SIDE = 'R' * On entry, the (m - 1) x n matrix C2 if SIDE = 'L', or the * m x (n - 1) matrix C2 if SIDE = 'R'. * * On exit, rows 2:m of P*C if SIDE = 'L', or columns 2:m of C*P * if SIDE = 'R'. * * LDC (input) INTEGER * The leading dimension of the arrays C1 and C2. LDC >= (1,M). * * WORK (workspace) REAL array, dimension * (N) if SIDE = 'L' * (M) if SIDE = 'R' * * ===================================================================== * * .. Parameters .. REAL ONE, ZERO PARAMETER ( ONE = 1.0E+0, ZERO = 0.0E+0 ) * .. * .. External Subroutines .. EXTERNAL SAXPY, SCOPY, SGEMV, SGER * .. * .. External Functions .. LOGICAL LSAME EXTERNAL LSAME * .. * .. Intrinsic Functions .. INTRINSIC MIN * .. * .. Executable Statements .. * IF( ( MIN( M, N ).EQ.0 ) .OR. ( TAU.EQ.ZERO ) ) $ RETURN * IF( LSAME( SIDE, 'L' ) ) THEN * * w := (C1 + v**T * C2)**T * CALL SCOPY( N, C1, LDC, WORK, 1 ) CALL SGEMV( 'Transpose', M-1, N, ONE, C2, LDC, V, INCV, ONE, $ WORK, 1 ) * * [ C1 ] := [ C1 ] - tau* [ 1 ] * w**T * [ C2 ] [ C2 ] [ v ] * CALL SAXPY( N, -TAU, WORK, 1, C1, LDC ) CALL SGER( M-1, N, -TAU, V, INCV, WORK, 1, C2, LDC ) * ELSE IF( LSAME( SIDE, 'R' ) ) THEN * * w := C1 + C2 * v * CALL SCOPY( M, C1, 1, WORK, 1 ) CALL SGEMV( 'No transpose', M, N-1, ONE, C2, LDC, V, INCV, ONE, $ WORK, 1 ) * * [ C1, C2 ] := [ C1, C2 ] - tau* w * [ 1 , v**T] * CALL SAXPY( M, -TAU, WORK, 1, C1, 1 ) CALL SGER( M, N-1, -TAU, WORK, 1, V, INCV, C2, LDC ) END IF * RETURN * * End of SLATZM * END |