Move LAPACK trunk into position.

1 files changed, 328 insertions, 0 deletions

diff --git a/SRC/zlabrd.f b/SRC/zlabrd.f
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+      SUBROUTINE ZLABRD( M, N, NB, A, LDA, D, E, TAUQ, TAUP, X, LDX, Y,
+     $                   LDY )
+*
+*  -- LAPACK auxiliary routine (version 3.1) --
+*     Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
+*     November 2006
+*
+*     .. Scalar Arguments ..
+      INTEGER            LDA, LDX, LDY, M, N, NB
+*     ..
+*     .. Array Arguments ..
+      DOUBLE PRECISION   D( * ), E( * )
+      COMPLEX*16         A( LDA, * ), TAUP( * ), TAUQ( * ), X( LDX, * ),
+     $                   Y( LDY, * )
+*     ..
+*
+*  Purpose
+*  =======
+*
+*  ZLABRD reduces the first NB rows and columns of a complex general
+*  m by n matrix A to upper or lower real bidiagonal form by a unitary
+*  transformation Q' * A * P, and returns the matrices X and Y which
+*  are needed to apply the transformation to the unreduced part of A.
+*
+*  If m >= n, A is reduced to upper bidiagonal form; if m < n, to lower
+*  bidiagonal form.
+*
+*  This is an auxiliary routine called by ZGEBRD
+*
+*  Arguments
+*  =========
+*
+*  M       (input) INTEGER
+*          The number of rows in the matrix A.
+*
+*  N       (input) INTEGER
+*          The number of columns in the matrix A.
+*
+*  NB      (input) INTEGER
+*          The number of leading rows and columns of A to be reduced.
+*
+*  A       (input/output) COMPLEX*16 array, dimension (LDA,N)
+*          On entry, the m by n general matrix to be reduced.
+*          On exit, the first NB rows and columns of the matrix are
+*          overwritten; the rest of the array is unchanged.
+*          If m >= n, elements on and below the diagonal in the first NB
+*            columns, with the array TAUQ, represent the unitary
+*            matrix Q as a product of elementary reflectors; and
+*            elements above the diagonal in the first NB rows, with the
+*            array TAUP, represent the unitary matrix P as a product
+*            of elementary reflectors.
+*          If m < n, elements below the diagonal in the first NB
+*            columns, with the array TAUQ, represent the unitary
+*            matrix Q as a product of elementary reflectors, and
+*            elements on and above the diagonal in the first NB rows,
+*            with the array TAUP, represent the unitary matrix P as
+*            a product of elementary reflectors.
+*          See Further Details.
+*
+*  LDA     (input) INTEGER
+*          The leading dimension of the array A.  LDA >= max(1,M).
+*
+*  D       (output) DOUBLE PRECISION array, dimension (NB)
+*          The diagonal elements of the first NB rows and columns of
+*          the reduced matrix.  D(i) = A(i,i).
+*
+*  E       (output) DOUBLE PRECISION array, dimension (NB)
+*          The off-diagonal elements of the first NB rows and columns of
+*          the reduced matrix.
+*
+*  TAUQ    (output) COMPLEX*16 array dimension (NB)
+*          The scalar factors of the elementary reflectors which
+*          represent the unitary matrix Q. See Further Details.
+*
+*  TAUP    (output) COMPLEX*16 array, dimension (NB)
+*          The scalar factors of the elementary reflectors which
+*          represent the unitary matrix P. See Further Details.
+*
+*  X       (output) COMPLEX*16 array, dimension (LDX,NB)
+*          The m-by-nb matrix X required to update the unreduced part
+*          of A.
+*
+*  LDX     (input) INTEGER
+*          The leading dimension of the array X. LDX >= max(1,M).
+*
+*  Y       (output) COMPLEX*16 array, dimension (LDY,NB)
+*          The n-by-nb matrix Y required to update the unreduced part
+*          of A.
+*
+*  LDY     (input) INTEGER
+*          The leading dimension of the array Y. LDY >= max(1,N).
+*
+*  Further Details
+*  ===============
+*
+*  The matrices Q and P are represented as products of elementary
+*  reflectors:
+*
+*     Q = H(1) H(2) . . . H(nb)  and  P = G(1) G(2) . . . G(nb)
+*
+*  Each H(i) and G(i) has the form:
+*
+*     H(i) = I - tauq * v * v'  and G(i) = I - taup * u * u'
+*
+*  where tauq and taup are complex scalars, and v and u are complex
+*  vectors.
+*
+*  If m >= n, v(1:i-1) = 0, v(i) = 1, and v(i:m) is stored on exit in
+*  A(i:m,i); u(1:i) = 0, u(i+1) = 1, and u(i+1:n) is stored on exit in
+*  A(i,i+1:n); tauq is stored in TAUQ(i) and taup in TAUP(i).
+*
+*  If m < n, v(1:i) = 0, v(i+1) = 1, and v(i+1:m) is stored on exit in
+*  A(i+2:m,i); u(1:i-1) = 0, u(i) = 1, and u(i:n) is stored on exit in
+*  A(i,i+1:n); tauq is stored in TAUQ(i) and taup in TAUP(i).
+*
+*  The elements of the vectors v and u together form the m-by-nb matrix
+*  V and the nb-by-n matrix U' which are needed, with X and Y, to apply
+*  the transformation to the unreduced part of the matrix, using a block
+*  update of the form:  A := A - V*Y' - X*U'.
+*
+*  The contents of A on exit are illustrated by the following examples
+*  with nb = 2:
+*
+*  m = 6 and n = 5 (m > n):          m = 5 and n = 6 (m < n):
+*
+*    (  1   1   u1  u1  u1 )           (  1   u1  u1  u1  u1  u1 )
+*    (  v1  1   1   u2  u2 )           (  1   1   u2  u2  u2  u2 )
+*    (  v1  v2  a   a   a  )           (  v1  1   a   a   a   a  )
+*    (  v1  v2  a   a   a  )           (  v1  v2  a   a   a   a  )
+*    (  v1  v2  a   a   a  )           (  v1  v2  a   a   a   a  )
+*    (  v1  v2  a   a   a  )
+*
+*  where a denotes an element of the original matrix which is unchanged,
+*  vi denotes an element of the vector defining H(i), and ui an element
+*  of the vector defining G(i).
+*
+*  =====================================================================
+*
+*     .. Parameters ..
+      COMPLEX*16         ZERO, ONE
+      PARAMETER          ( ZERO = ( 0.0D+0, 0.0D+0 ),
+     $                   ONE = ( 1.0D+0, 0.0D+0 ) )
+*     ..
+*     .. Local Scalars ..
+      INTEGER            I
+      COMPLEX*16         ALPHA
+*     ..
+*     .. External Subroutines ..
+      EXTERNAL           ZGEMV, ZLACGV, ZLARFG, ZSCAL
+*     ..
+*     .. Intrinsic Functions ..
+      INTRINSIC          MIN
+*     ..
+*     .. Executable Statements ..
+*
+*     Quick return if possible
+*
+      IF( M.LE.0 .OR. N.LE.0 )
+     $   RETURN
+*
+      IF( M.GE.N ) THEN
+*
+*        Reduce to upper bidiagonal form
+*
+         DO 10 I = 1, NB
+*
+*           Update A(i:m,i)
+*
+            CALL ZLACGV( I-1, Y( I, 1 ), LDY )
+            CALL ZGEMV( 'No transpose', M-I+1, I-1, -ONE, A( I, 1 ),
+     $                  LDA, Y( I, 1 ), LDY, ONE, A( I, I ), 1 )
+            CALL ZLACGV( I-1, Y( I, 1 ), LDY )
+            CALL ZGEMV( 'No transpose', M-I+1, I-1, -ONE, X( I, 1 ),
+     $                  LDX, A( 1, I ), 1, ONE, A( I, I ), 1 )
+*
+*           Generate reflection Q(i) to annihilate A(i+1:m,i)
+*
+            ALPHA = A( I, I )
+            CALL ZLARFG( M-I+1, ALPHA, A( MIN( I+1, M ), I ), 1,
+     $                   TAUQ( I ) )
+            D( I ) = ALPHA
+            IF( I.LT.N ) THEN
+               A( I, I ) = ONE
+*
+*              Compute Y(i+1:n,i)
+*
+               CALL ZGEMV( 'Conjugate transpose', M-I+1, N-I, ONE,
+     $                     A( I, I+1 ), LDA, A( I, I ), 1, ZERO,
+     $                     Y( I+1, I ), 1 )
+               CALL ZGEMV( 'Conjugate transpose', M-I+1, I-1, ONE,
+     $                     A( I, 1 ), LDA, A( I, I ), 1, ZERO,
+     $                     Y( 1, I ), 1 )
+               CALL ZGEMV( 'No transpose', N-I, I-1, -ONE, Y( I+1, 1 ),
+     $                     LDY, Y( 1, I ), 1, ONE, Y( I+1, I ), 1 )
+               CALL ZGEMV( 'Conjugate transpose', M-I+1, I-1, ONE,
+     $                     X( I, 1 ), LDX, A( I, I ), 1, ZERO,
+     $                     Y( 1, I ), 1 )
+               CALL ZGEMV( 'Conjugate transpose', I-1, N-I, -ONE,
+     $                     A( 1, I+1 ), LDA, Y( 1, I ), 1, ONE,
+     $                     Y( I+1, I ), 1 )
+               CALL ZSCAL( N-I, TAUQ( I ), Y( I+1, I ), 1 )
+*
+*              Update A(i,i+1:n)
+*
+               CALL ZLACGV( N-I, A( I, I+1 ), LDA )
+               CALL ZLACGV( I, A( I, 1 ), LDA )
+               CALL ZGEMV( 'No transpose', N-I, I, -ONE, Y( I+1, 1 ),
+     $                     LDY, A( I, 1 ), LDA, ONE, A( I, I+1 ), LDA )
+               CALL ZLACGV( I, A( I, 1 ), LDA )
+               CALL ZLACGV( I-1, X( I, 1 ), LDX )
+               CALL ZGEMV( 'Conjugate transpose', I-1, N-I, -ONE,
+     $                     A( 1, I+1 ), LDA, X( I, 1 ), LDX, ONE,
+     $                     A( I, I+1 ), LDA )
+               CALL ZLACGV( I-1, X( I, 1 ), LDX )
+*
+*              Generate reflection P(i) to annihilate A(i,i+2:n)
+*
+               ALPHA = A( I, I+1 )
+               CALL ZLARFG( N-I, ALPHA, A( I, MIN( I+2, N ) ), LDA,
+     $                      TAUP( I ) )
+               E( I ) = ALPHA
+               A( I, I+1 ) = ONE
+*
+*              Compute X(i+1:m,i)
+*
+               CALL ZGEMV( 'No transpose', M-I, N-I, ONE, A( I+1, I+1 ),
+     $                     LDA, A( I, I+1 ), LDA, ZERO, X( I+1, I ), 1 )
+               CALL ZGEMV( 'Conjugate transpose', N-I, I, ONE,
+     $                     Y( I+1, 1 ), LDY, A( I, I+1 ), LDA, ZERO,
+     $                     X( 1, I ), 1 )
+               CALL ZGEMV( 'No transpose', M-I, I, -ONE, A( I+1, 1 ),
+     $                     LDA, X( 1, I ), 1, ONE, X( I+1, I ), 1 )
+               CALL ZGEMV( 'No transpose', I-1, N-I, ONE, A( 1, I+1 ),
+     $                     LDA, A( I, I+1 ), LDA, ZERO, X( 1, I ), 1 )
+               CALL ZGEMV( 'No transpose', M-I, I-1, -ONE, X( I+1, 1 ),
+     $                     LDX, X( 1, I ), 1, ONE, X( I+1, I ), 1 )
+               CALL ZSCAL( M-I, TAUP( I ), X( I+1, I ), 1 )
+               CALL ZLACGV( N-I, A( I, I+1 ), LDA )
+            END IF
+   10    CONTINUE
+      ELSE
+*
+*        Reduce to lower bidiagonal form
+*
+         DO 20 I = 1, NB
+*
+*           Update A(i,i:n)
+*
+            CALL ZLACGV( N-I+1, A( I, I ), LDA )
+            CALL ZLACGV( I-1, A( I, 1 ), LDA )
+            CALL ZGEMV( 'No transpose', N-I+1, I-1, -ONE, Y( I, 1 ),
+     $                  LDY, A( I, 1 ), LDA, ONE, A( I, I ), LDA )
+            CALL ZLACGV( I-1, A( I, 1 ), LDA )
+            CALL ZLACGV( I-1, X( I, 1 ), LDX )
+            CALL ZGEMV( 'Conjugate transpose', I-1, N-I+1, -ONE,
+     $                  A( 1, I ), LDA, X( I, 1 ), LDX, ONE, A( I, I ),
+     $                  LDA )
+            CALL ZLACGV( I-1, X( I, 1 ), LDX )
+*
+*           Generate reflection P(i) to annihilate A(i,i+1:n)
+*
+            ALPHA = A( I, I )
+            CALL ZLARFG( N-I+1, ALPHA, A( I, MIN( I+1, N ) ), LDA,
+     $                   TAUP( I ) )
+            D( I ) = ALPHA
+            IF( I.LT.M ) THEN
+               A( I, I ) = ONE
+*
+*              Compute X(i+1:m,i)
+*
+               CALL ZGEMV( 'No transpose', M-I, N-I+1, ONE, A( I+1, I ),
+     $                     LDA, A( I, I ), LDA, ZERO, X( I+1, I ), 1 )
+               CALL ZGEMV( 'Conjugate transpose', N-I+1, I-1, ONE,
+     $                     Y( I, 1 ), LDY, A( I, I ), LDA, ZERO,
+     $                     X( 1, I ), 1 )
+               CALL ZGEMV( 'No transpose', M-I, I-1, -ONE, A( I+1, 1 ),
+     $                     LDA, X( 1, I ), 1, ONE, X( I+1, I ), 1 )
+               CALL ZGEMV( 'No transpose', I-1, N-I+1, ONE, A( 1, I ),
+     $                     LDA, A( I, I ), LDA, ZERO, X( 1, I ), 1 )
+               CALL ZGEMV( 'No transpose', M-I, I-1, -ONE, X( I+1, 1 ),
+     $                     LDX, X( 1, I ), 1, ONE, X( I+1, I ), 1 )
+               CALL ZSCAL( M-I, TAUP( I ), X( I+1, I ), 1 )
+               CALL ZLACGV( N-I+1, A( I, I ), LDA )
+*
+*              Update A(i+1:m,i)
+*
+               CALL ZLACGV( I-1, Y( I, 1 ), LDY )
+               CALL ZGEMV( 'No transpose', M-I, I-1, -ONE, A( I+1, 1 ),
+     $                     LDA, Y( I, 1 ), LDY, ONE, A( I+1, I ), 1 )
+               CALL ZLACGV( I-1, Y( I, 1 ), LDY )
+               CALL ZGEMV( 'No transpose', M-I, I, -ONE, X( I+1, 1 ),
+     $                     LDX, A( 1, I ), 1, ONE, A( I+1, I ), 1 )
+*
+*              Generate reflection Q(i) to annihilate A(i+2:m,i)
+*
+               ALPHA = A( I+1, I )
+               CALL ZLARFG( M-I, ALPHA, A( MIN( I+2, M ), I ), 1,
+     $                      TAUQ( I ) )
+               E( I ) = ALPHA
+               A( I+1, I ) = ONE
+*
+*              Compute Y(i+1:n,i)
+*
+               CALL ZGEMV( 'Conjugate transpose', M-I, N-I, ONE,
+     $                     A( I+1, I+1 ), LDA, A( I+1, I ), 1, ZERO,
+     $                     Y( I+1, I ), 1 )
+               CALL ZGEMV( 'Conjugate transpose', M-I, I-1, ONE,
+     $                     A( I+1, 1 ), LDA, A( I+1, I ), 1, ZERO,
+     $                     Y( 1, I ), 1 )
+               CALL ZGEMV( 'No transpose', N-I, I-1, -ONE, Y( I+1, 1 ),
+     $                     LDY, Y( 1, I ), 1, ONE, Y( I+1, I ), 1 )
+               CALL ZGEMV( 'Conjugate transpose', M-I, I, ONE,
+     $                     X( I+1, 1 ), LDX, A( I+1, I ), 1, ZERO,
+     $                     Y( 1, I ), 1 )
+               CALL ZGEMV( 'Conjugate transpose', I, N-I, -ONE,
+     $                     A( 1, I+1 ), LDA, Y( 1, I ), 1, ONE,
+     $                     Y( I+1, I ), 1 )
+               CALL ZSCAL( N-I, TAUQ( I ), Y( I+1, I ), 1 )
+            ELSE
+               CALL ZLACGV( N-I+1, A( I, I ), LDA )
+            END IF
+   20    CONTINUE
+      END IF
+      RETURN
+*
+*     End of ZLABRD
+*
+      END