147 lines
4.2 KiB
FortranFixed
147 lines
4.2 KiB
FortranFixed
SUBROUTINE CLATZM( SIDE, M, N, V, INCV, TAU, C1, C2, LDC, WORK )
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*
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* -- LAPACK routine (version 3.1) --
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* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
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* November 2006
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*
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* .. Scalar Arguments ..
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CHARACTER SIDE
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INTEGER INCV, LDC, M, N
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COMPLEX TAU
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* ..
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* .. Array Arguments ..
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COMPLEX C1( LDC, * ), C2( LDC, * ), V( * ), WORK( * )
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* ..
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*
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* Purpose
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* =======
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*
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* This routine is deprecated and has been replaced by routine CUNMRZ.
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*
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* CLATZM applies a Householder matrix generated by CTZRQF to a matrix.
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*
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* Let P = I - tau*u*u', u = ( 1 ),
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* ( v )
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* where v is an (m-1) vector if SIDE = 'L', or a (n-1) vector if
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* SIDE = 'R'.
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*
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* If SIDE equals 'L', let
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* C = [ C1 ] 1
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* [ C2 ] m-1
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* n
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* Then C is overwritten by P*C.
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*
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* If SIDE equals 'R', let
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* C = [ C1, C2 ] m
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* 1 n-1
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* Then C is overwritten by C*P.
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*
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* Arguments
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* =========
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*
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* SIDE (input) CHARACTER*1
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* = 'L': form P * C
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* = 'R': form C * P
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*
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* M (input) INTEGER
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* The number of rows of the matrix C.
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*
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* N (input) INTEGER
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* The number of columns of the matrix C.
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*
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* V (input) COMPLEX array, dimension
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* (1 + (M-1)*abs(INCV)) if SIDE = 'L'
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* (1 + (N-1)*abs(INCV)) if SIDE = 'R'
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* The vector v in the representation of P. V is not used
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* if TAU = 0.
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*
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* INCV (input) INTEGER
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* The increment between elements of v. INCV <> 0
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*
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* TAU (input) COMPLEX
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* The value tau in the representation of P.
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*
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* C1 (input/output) COMPLEX array, dimension
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* (LDC,N) if SIDE = 'L'
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* (M,1) if SIDE = 'R'
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* On entry, the n-vector C1 if SIDE = 'L', or the m-vector C1
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* if SIDE = 'R'.
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*
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* On exit, the first row of P*C if SIDE = 'L', or the first
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* column of C*P if SIDE = 'R'.
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*
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* C2 (input/output) COMPLEX array, dimension
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* (LDC, N) if SIDE = 'L'
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* (LDC, N-1) if SIDE = 'R'
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* On entry, the (m - 1) x n matrix C2 if SIDE = 'L', or the
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* m x (n - 1) matrix C2 if SIDE = 'R'.
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*
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* On exit, rows 2:m of P*C if SIDE = 'L', or columns 2:m of C*P
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* if SIDE = 'R'.
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*
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* LDC (input) INTEGER
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* The leading dimension of the arrays C1 and C2.
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* LDC >= max(1,M).
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*
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* WORK (workspace) COMPLEX array, dimension
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* (N) if SIDE = 'L'
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* (M) if SIDE = 'R'
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*
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* =====================================================================
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*
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* .. Parameters ..
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COMPLEX ONE, ZERO
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PARAMETER ( ONE = ( 1.0E+0, 0.0E+0 ),
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$ ZERO = ( 0.0E+0, 0.0E+0 ) )
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* ..
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* .. External Subroutines ..
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EXTERNAL CAXPY, CCOPY, CGEMV, CGERC, CGERU, CLACGV
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* ..
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* .. External Functions ..
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LOGICAL LSAME
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EXTERNAL LSAME
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* ..
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* .. Intrinsic Functions ..
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INTRINSIC MIN
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* ..
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* .. Executable Statements ..
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*
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IF( ( MIN( M, N ).EQ.0 ) .OR. ( TAU.EQ.ZERO ) )
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$ RETURN
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*
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IF( LSAME( SIDE, 'L' ) ) THEN
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*
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* w := conjg( C1 + v' * C2 )
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*
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CALL CCOPY( N, C1, LDC, WORK, 1 )
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CALL CLACGV( N, WORK, 1 )
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CALL CGEMV( 'Conjugate transpose', M-1, N, ONE, C2, LDC, V,
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$ INCV, ONE, WORK, 1 )
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*
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* [ C1 ] := [ C1 ] - tau* [ 1 ] * w'
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* [ C2 ] [ C2 ] [ v ]
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*
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CALL CLACGV( N, WORK, 1 )
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CALL CAXPY( N, -TAU, WORK, 1, C1, LDC )
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CALL CGERU( M-1, N, -TAU, V, INCV, WORK, 1, C2, LDC )
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*
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ELSE IF( LSAME( SIDE, 'R' ) ) THEN
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*
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* w := C1 + C2 * v
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*
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CALL CCOPY( M, C1, 1, WORK, 1 )
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CALL CGEMV( 'No transpose', M, N-1, ONE, C2, LDC, V, INCV, ONE,
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$ WORK, 1 )
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*
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* [ C1, C2 ] := [ C1, C2 ] - tau* w * [ 1 , v']
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*
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CALL CAXPY( M, -TAU, WORK, 1, C1, 1 )
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CALL CGERC( M, N-1, -TAU, WORK, 1, V, INCV, C2, LDC )
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END IF
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*
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RETURN
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*
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* End of CLATZM
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*
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END
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