summaryrefslogtreecommitdiff
path: root/src/lib/lapack/zgehrd.f
diff options
context:
space:
mode:
authorjofret2009-04-28 07:17:00 +0000
committerjofret2009-04-28 07:17:00 +0000
commit8c8d2f518968ce7057eec6aa5cd5aec8faab861a (patch)
tree3dd1788b71d6a3ce2b73d2d475a3133580e17530 /src/lib/lapack/zgehrd.f
parent9f652ffc16a310ac6641a9766c5b9e2671e0e9cb (diff)
downloadscilab2c-8c8d2f518968ce7057eec6aa5cd5aec8faab861a.tar.gz
scilab2c-8c8d2f518968ce7057eec6aa5cd5aec8faab861a.tar.bz2
scilab2c-8c8d2f518968ce7057eec6aa5cd5aec8faab861a.zip
Moving lapack to right place
Diffstat (limited to 'src/lib/lapack/zgehrd.f')
-rw-r--r--src/lib/lapack/zgehrd.f273
1 files changed, 0 insertions, 273 deletions
diff --git a/src/lib/lapack/zgehrd.f b/src/lib/lapack/zgehrd.f
deleted file mode 100644
index 83c1aa32..00000000
--- a/src/lib/lapack/zgehrd.f
+++ /dev/null
@@ -1,273 +0,0 @@
- SUBROUTINE ZGEHRD( N, ILO, IHI, A, LDA, TAU, WORK, LWORK, INFO )
-*
-* -- LAPACK routine (version 3.1) --
-* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
-* November 2006
-*
-* .. Scalar Arguments ..
- INTEGER IHI, ILO, INFO, LDA, LWORK, N
-* ..
-* .. Array Arguments ..
- COMPLEX*16 A( LDA, * ), TAU( * ), WORK( * )
-* ..
-*
-* Purpose
-* =======
-*
-* ZGEHRD reduces a complex general matrix A to upper Hessenberg form H by
-* an unitary similarity transformation: Q' * A * Q = H .
-*
-* Arguments
-* =========
-*
-* N (input) INTEGER
-* The order of the matrix A. N >= 0.
-*
-* ILO (input) INTEGER
-* IHI (input) INTEGER
-* It is assumed that A is already upper triangular in rows
-* and columns 1:ILO-1 and IHI+1:N. ILO and IHI are normally
-* set by a previous call to ZGEBAL; otherwise they should be
-* set to 1 and N respectively. See Further Details.
-* 1 <= ILO <= IHI <= N, if N > 0; ILO=1 and IHI=0, if N=0.
-*
-* A (input/output) COMPLEX*16 array, dimension (LDA,N)
-* On entry, the N-by-N general matrix to be reduced.
-* On exit, the upper triangle and the first subdiagonal of A
-* are overwritten with the upper Hessenberg matrix H, and the
-* elements below the first subdiagonal, with the array TAU,
-* represent the unitary matrix Q as a product of elementary
-* reflectors. See Further Details.
-*
-* LDA (input) INTEGER
-* The leading dimension of the array A. LDA >= max(1,N).
-*
-* TAU (output) COMPLEX*16 array, dimension (N-1)
-* The scalar factors of the elementary reflectors (see Further
-* Details). Elements 1:ILO-1 and IHI:N-1 of TAU are set to
-* zero.
-*
-* WORK (workspace/output) COMPLEX*16 array, dimension (LWORK)
-* On exit, if INFO = 0, WORK(1) returns the optimal LWORK.
-*
-* LWORK (input) INTEGER
-* The length of the array WORK. LWORK >= max(1,N).
-* For optimum performance LWORK >= N*NB, where NB is the
-* optimal blocksize.
-*
-* If LWORK = -1, then a workspace query is assumed; the routine
-* only calculates the optimal size of the WORK array, returns
-* this value as the first entry of the WORK array, and no error
-* message related to LWORK is issued by XERBLA.
-*
-* INFO (output) INTEGER
-* = 0: successful exit
-* < 0: if INFO = -i, the i-th argument had an illegal value.
-*
-* Further Details
-* ===============
-*
-* The matrix Q is represented as a product of (ihi-ilo) elementary
-* reflectors
-*
-* Q = H(ilo) H(ilo+1) . . . H(ihi-1).
-*
-* Each H(i) has the form
-*
-* H(i) = I - tau * v * v'
-*
-* where tau is a complex scalar, and v is a complex vector with
-* v(1:i) = 0, v(i+1) = 1 and v(ihi+1:n) = 0; v(i+2:ihi) is stored on
-* exit in A(i+2:ihi,i), and tau in TAU(i).
-*
-* The contents of A are illustrated by the following example, with
-* n = 7, ilo = 2 and ihi = 6:
-*
-* on entry, on exit,
-*
-* ( a a a a a a a ) ( a a h h h h a )
-* ( a a a a a a ) ( a h h h h a )
-* ( a a a a a a ) ( h h h h h h )
-* ( a a a a a a ) ( v2 h h h h h )
-* ( a a a a a a ) ( v2 v3 h h h h )
-* ( a a a a a a ) ( v2 v3 v4 h h h )
-* ( a ) ( a )
-*
-* where a denotes an element of the original matrix A, h denotes a
-* modified element of the upper Hessenberg matrix H, and vi denotes an
-* element of the vector defining H(i).
-*
-* This file is a slight modification of LAPACK-3.0's ZGEHRD
-* subroutine incorporating improvements proposed by Quintana-Orti and
-* Van de Geijn (2005).
-*
-* =====================================================================
-*
-* .. Parameters ..
- INTEGER NBMAX, LDT
- PARAMETER ( NBMAX = 64, LDT = NBMAX+1 )
- COMPLEX*16 ZERO, ONE
- PARAMETER ( ZERO = ( 0.0D+0, 0.0D+0 ),
- $ ONE = ( 1.0D+0, 0.0D+0 ) )
-* ..
-* .. Local Scalars ..
- LOGICAL LQUERY
- INTEGER I, IB, IINFO, IWS, J, LDWORK, LWKOPT, NB,
- $ NBMIN, NH, NX
- COMPLEX*16 EI
-* ..
-* .. Local Arrays ..
- COMPLEX*16 T( LDT, NBMAX )
-* ..
-* .. External Subroutines ..
- EXTERNAL ZAXPY, ZGEHD2, ZGEMM, ZLAHR2, ZLARFB, ZTRMM,
- $ XERBLA
-* ..
-* .. Intrinsic Functions ..
- INTRINSIC MAX, MIN
-* ..
-* .. External Functions ..
- INTEGER ILAENV
- EXTERNAL ILAENV
-* ..
-* .. Executable Statements ..
-*
-* Test the input parameters
-*
- INFO = 0
- NB = MIN( NBMAX, ILAENV( 1, 'ZGEHRD', ' ', N, ILO, IHI, -1 ) )
- LWKOPT = N*NB
- WORK( 1 ) = LWKOPT
- LQUERY = ( LWORK.EQ.-1 )
- IF( N.LT.0 ) THEN
- INFO = -1
- ELSE IF( ILO.LT.1 .OR. ILO.GT.MAX( 1, N ) ) THEN
- INFO = -2
- ELSE IF( IHI.LT.MIN( ILO, N ) .OR. IHI.GT.N ) THEN
- INFO = -3
- ELSE IF( LDA.LT.MAX( 1, N ) ) THEN
- INFO = -5
- ELSE IF( LWORK.LT.MAX( 1, N ) .AND. .NOT.LQUERY ) THEN
- INFO = -8
- END IF
- IF( INFO.NE.0 ) THEN
- CALL XERBLA( 'ZGEHRD', -INFO )
- RETURN
- ELSE IF( LQUERY ) THEN
- RETURN
- END IF
-*
-* Set elements 1:ILO-1 and IHI:N-1 of TAU to zero
-*
- DO 10 I = 1, ILO - 1
- TAU( I ) = ZERO
- 10 CONTINUE
- DO 20 I = MAX( 1, IHI ), N - 1
- TAU( I ) = ZERO
- 20 CONTINUE
-*
-* Quick return if possible
-*
- NH = IHI - ILO + 1
- IF( NH.LE.1 ) THEN
- WORK( 1 ) = 1
- RETURN
- END IF
-*
-* Determine the block size
-*
- NB = MIN( NBMAX, ILAENV( 1, 'ZGEHRD', ' ', N, ILO, IHI, -1 ) )
- NBMIN = 2
- IWS = 1
- IF( NB.GT.1 .AND. NB.LT.NH ) THEN
-*
-* Determine when to cross over from blocked to unblocked code
-* (last block is always handled by unblocked code)
-*
- NX = MAX( NB, ILAENV( 3, 'ZGEHRD', ' ', N, ILO, IHI, -1 ) )
- IF( NX.LT.NH ) THEN
-*
-* Determine if workspace is large enough for blocked code
-*
- IWS = N*NB
- IF( LWORK.LT.IWS ) THEN
-*
-* Not enough workspace to use optimal NB: determine the
-* minimum value of NB, and reduce NB or force use of
-* unblocked code
-*
- NBMIN = MAX( 2, ILAENV( 2, 'ZGEHRD', ' ', N, ILO, IHI,
- $ -1 ) )
- IF( LWORK.GE.N*NBMIN ) THEN
- NB = LWORK / N
- ELSE
- NB = 1
- END IF
- END IF
- END IF
- END IF
- LDWORK = N
-*
- IF( NB.LT.NBMIN .OR. NB.GE.NH ) THEN
-*
-* Use unblocked code below
-*
- I = ILO
-*
- ELSE
-*
-* Use blocked code
-*
- DO 40 I = ILO, IHI - 1 - NX, NB
- IB = MIN( NB, IHI-I )
-*
-* Reduce columns i:i+ib-1 to Hessenberg form, returning the
-* matrices V and T of the block reflector H = I - V*T*V'
-* which performs the reduction, and also the matrix Y = A*V*T
-*
- CALL ZLAHR2( IHI, I, IB, A( 1, I ), LDA, TAU( I ), T, LDT,
- $ WORK, LDWORK )
-*
-* Apply the block reflector H to A(1:ihi,i+ib:ihi) from the
-* right, computing A := A - Y * V'. V(i+ib,ib-1) must be set
-* to 1
-*
- EI = A( I+IB, I+IB-1 )
- A( I+IB, I+IB-1 ) = ONE
- CALL ZGEMM( 'No transpose', 'Conjugate transpose',
- $ IHI, IHI-I-IB+1,
- $ IB, -ONE, WORK, LDWORK, A( I+IB, I ), LDA, ONE,
- $ A( 1, I+IB ), LDA )
- A( I+IB, I+IB-1 ) = EI
-*
-* Apply the block reflector H to A(1:i,i+1:i+ib-1) from the
-* right
-*
- CALL ZTRMM( 'Right', 'Lower', 'Conjugate transpose',
- $ 'Unit', I, IB-1,
- $ ONE, A( I+1, I ), LDA, WORK, LDWORK )
- DO 30 J = 0, IB-2
- CALL ZAXPY( I, -ONE, WORK( LDWORK*J+1 ), 1,
- $ A( 1, I+J+1 ), 1 )
- 30 CONTINUE
-*
-* Apply the block reflector H to A(i+1:ihi,i+ib:n) from the
-* left
-*
- CALL ZLARFB( 'Left', 'Conjugate transpose', 'Forward',
- $ 'Columnwise',
- $ IHI-I, N-I-IB+1, IB, A( I+1, I ), LDA, T, LDT,
- $ A( I+1, I+IB ), LDA, WORK, LDWORK )
- 40 CONTINUE
- END IF
-*
-* Use unblocked code to reduce the rest of the matrix
-*
- CALL ZGEHD2( N, I, IHI, A, LDA, TAU, WORK, IINFO )
- WORK( 1 ) = IWS
-*
- RETURN
-*
-* End of ZGEHRD
-*
- END