slarzb.f(3)

NAME
slarzb.f -

SYNOPSIS

  Functions/Subroutines

subroutine slarzb (SIDE, TRANS, DIRECT, STOREV, M, N, K, L, V, LDV, T, LDT, C, LDC, WORK, LDWORK)
SLARZB applies a block reflector or its transpose to a general matrix.

Function/Subroutine Documentation

  subroutine slarzb (characterSIDE, characterTRANS, characterDIRECT, characterSTOREV, integerM, integerN, integerK, integerL, real, dimension( ldv, * )V, integerLDV, real, dimension( ldt, * )T, integerLDT, real, dimension( ldc, * )C, integerLDC, real, dimension( ldwork, * )WORK, integerLDWORK)

SLARZB applies a block reflector or its transpose to a general matrix.

Purpose:

     SLARZB applies a real block reflector H or its transpose H**T to
     a real distributed M-by-N  C from the left or the right.

     Currently, only STOREV = 'R' and DIRECT = 'B' are supported.

Parameters:
    SIDE

              SIDE is CHARACTER*1
              = 'L': apply H or H**T from the Left
              = 'R': apply H or H**T from the Right

    TRANS

              TRANS is CHARACTER*1
              = 'N': apply H (No transpose)
              = 'C': apply H**T (Transpose)

    DIRECT

              DIRECT is CHARACTER*1
              Indicates how H is formed from a product of elementary
              reflectors
              = 'F': H = H(1) H(2) . . . H(k) (Forward, not supported yet)
              = 'B': H = H(k) . . . H(2) H(1) (Backward)

    STOREV

              STOREV is CHARACTER*1
              Indicates how the vectors which define the elementary
              reflectors are stored:
              = 'C': Columnwise                        (not supported yet)
              = 'R': Rowwise

    M

              M is INTEGER
              The number of rows of the matrix C.

    N

              N is INTEGER
              The number of columns of the matrix C.

    K

              K is INTEGER
              The order of the matrix T (= the number of elementary
              reflectors whose product defines the block reflector).

    L

              L is INTEGER
              The number of columns of the matrix V containing the
              meaningful part of the Householder reflectors.
              If SIDE = 'L', M >= L >= 0, if SIDE = 'R', N >= L >= 0.

    V

              V is REAL array, dimension (LDV,NV).
              If STOREV = 'C', NV = K; if STOREV = 'R', NV = L.

    LDV

              LDV is INTEGER
              The leading dimension of the array V.
              If STOREV = 'C', LDV >= L; if STOREV = 'R', LDV >= K.

    T

              T is REAL array, dimension (LDT,K)
              The triangular K-by-K matrix T in the representation of the
              block reflector.

    LDT

              LDT is INTEGER
              The leading dimension of the array T. LDT >= K.

    C

              C is REAL array, dimension (LDC,N)
              On entry, the M-by-N matrix C.
              On exit, C is overwritten by H*C or H**T*C or C*H or C*H**T.

    LDC

              LDC is INTEGER
              The leading dimension of the array C. LDC >= max(1,M).

    WORK

              WORK is REAL array, dimension (LDWORK,K)

    LDWORK

              LDWORK is INTEGER
              The leading dimension of the array WORK.
              If SIDE = 'L', LDWORK >= max(1,N);
              if SIDE = 'R', LDWORK >= max(1,M).

Author:
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Date:
    September 2012

Contributors:
    A. Petitet, Computer Science Dept., Univ. of Tenn., Knoxville, USA

Further Details:

Definition at line 183 of file slarzb.f.

Author

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