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authorRenegade <Renegate@Renegates-MacBook-Pro.local>2016-11-06 20:35:15 -0500
committerRenegade <Renegate@Renegates-MacBook-Pro.local>2016-11-06 20:35:15 -0500
commitb9c9d7631188cdf4c658a808a0748dbef848b863 (patch)
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adding the 2stage symmetric eigenvalue routines drivers checking
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+*> \brief \b CLARFY
+*
+* =========== DOCUMENTATION ===========
+*
+* Online html documentation available at
+* http://www.netlib.org/lapack/explore-html/
+*
+* Definition:
+* ===========
+*
+* SUBROUTINE CLARFY( UPLO, N, V, INCV, TAU, C, LDC, WORK )
+*
+* .. Scalar Arguments ..
+* CHARACTER UPLO
+* INTEGER INCV, LDC, N
+* COMPLEX TAU
+* ..
+* .. Array Arguments ..
+* COMPLEX C( LDC, * ), V( * ), WORK( * )
+* ..
+*
+*
+*> \par Purpose:
+* =============
+*>
+*> \verbatim
+*>
+*> CLARFY applies an elementary reflector, or Householder matrix, H,
+*> to an n x n Hermitian matrix C, from both the left and the right.
+*>
+*> H is represented in the form
+*>
+*> H = I - tau * v * v'
+*>
+*> where tau is a scalar and v is a vector.
+*>
+*> If tau is zero, then H is taken to be the unit matrix.
+*> \endverbatim
+*
+* Arguments:
+* ==========
+*
+*> \param[in] UPLO
+*> \verbatim
+*> UPLO is CHARACTER*1
+*> Specifies whether the upper or lower triangular part of the
+*> Hermitian matrix C is stored.
+*> = 'U': Upper triangle
+*> = 'L': Lower triangle
+*> \endverbatim
+*>
+*> \param[in] N
+*> \verbatim
+*> N is INTEGER
+*> The number of rows and columns of the matrix C. N >= 0.
+*> \endverbatim
+*>
+*> \param[in] V
+*> \verbatim
+*> V is COMPLEX array, dimension
+*> (1 + (N-1)*abs(INCV))
+*> The vector v as described above.
+*> \endverbatim
+*>
+*> \param[in] INCV
+*> \verbatim
+*> INCV is INTEGER
+*> The increment between successive elements of v. INCV must
+*> not be zero.
+*> \endverbatim
+*>
+*> \param[in] TAU
+*> \verbatim
+*> TAU is COMPLEX
+*> The value tau as described above.
+*> \endverbatim
+*>
+*> \param[in,out] C
+*> \verbatim
+*> C is COMPLEX array, dimension (LDC, N)
+*> On entry, the matrix C.
+*> On exit, C is overwritten by H * C * H'.
+*> \endverbatim
+*>
+*> \param[in] LDC
+*> \verbatim
+*> LDC is INTEGER
+*> The leading dimension of the array C. LDC >= max( 1, N ).
+*> \endverbatim
+*>
+*> \param[out] WORK
+*> \verbatim
+*> WORK is COMPLEX array, dimension (N)
+*> \endverbatim
+*
+* Authors:
+* ========
+*
+*> \author Univ. of Tennessee
+*> \author Univ. of California Berkeley
+*> \author Univ. of Colorado Denver
+*> \author NAG Ltd.
+*
+*> \date November 2011
+*
+*> \ingroup complex_eig
+*
+* =====================================================================
+ SUBROUTINE CLARFY( UPLO, N, V, INCV, TAU, C, LDC, WORK )
+*
+* -- LAPACK test routine (version 3.4.0) --
+* -- LAPACK is a software package provided by Univ. of Tennessee, --
+* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
+* November 2011
+*
+* .. Scalar Arguments ..
+ CHARACTER UPLO
+ INTEGER INCV, LDC, N
+ COMPLEX TAU
+* ..
+* .. Array Arguments ..
+ COMPLEX C( LDC, * ), V( * ), WORK( * )
+* ..
+*
+* =====================================================================
+*
+* .. Parameters ..
+ COMPLEX ONE, ZERO, HALF
+ PARAMETER ( ONE = ( 1.0E+0, 0.0E+0 ),
+ $ ZERO = ( 0.0E+0, 0.0E+0 ),
+ $ HALF = ( 0.5E+0, 0.0E+0 ) )
+* ..
+* .. Local Scalars ..
+ COMPLEX ALPHA
+* ..
+* .. External Subroutines ..
+ EXTERNAL CAXPY, CHEMV, CHER2
+* ..
+* .. External Functions ..
+ COMPLEX CDOTC
+ EXTERNAL CDOTC
+* ..
+* .. Executable Statements ..
+*
+ IF( TAU.EQ.ZERO )
+ $ RETURN
+*
+* Form w:= C * v
+*
+ CALL CHEMV( UPLO, N, ONE, C, LDC, V, INCV, ZERO, WORK, 1 )
+*
+ ALPHA = -HALF*TAU*CDOTC( N, WORK, 1, V, INCV )
+ CALL CAXPY( N, ALPHA, V, INCV, WORK, 1 )
+*
+* C := C - v * w' - w * v'
+*
+ CALL CHER2( UPLO, N, -TAU, V, INCV, WORK, 1, C, LDC )
+*
+ RETURN
+*
+* End of CLARFY
+*
+ END