1DLARFB(1)           LAPACK auxiliary routine (version 3.2)           DLARFB(1)
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NAME

6       DLARFB - applies a real block reflector H or its transpose H' to a real
7       m by n matrix C, from either the left or the right
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SYNOPSIS

10       SUBROUTINE DLARFB( SIDE, TRANS, DIRECT, STOREV, M, N,  K,  V,  LDV,  T,
11                          LDT, C, LDC, WORK, LDWORK )
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13           IMPLICIT       NONE
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15           CHARACTER      DIRECT, SIDE, STOREV, TRANS
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17           INTEGER        K, LDC, LDT, LDV, LDWORK, M, N
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19           DOUBLE         PRECISION  C(  LDC,  *  ), T( LDT, * ), V( LDV, * ),
20                          WORK( LDWORK, * )
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PURPOSE

23       DLARFB applies a real block reflector H or its transpose H' to a real m
24       by n matrix C, from either the left or the right.
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ARGUMENTS

27       SIDE    (input) CHARACTER*1
28               = 'L': apply H or H' from the Left
29               = 'R': apply H or H' from the Right
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31       TRANS   (input) CHARACTER*1
32               = 'N': apply H (No transpose)
33               = 'T': apply H' (Transpose)
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35       DIRECT  (input) CHARACTER*1
36               Indicates  how H is formed from a product of elementary reflec‐
37               tors = 'F': H = H(1) H(2) . . . H(k) (Forward)
38               = 'B': H = H(k) . . . H(2) H(1) (Backward)
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40       STOREV  (input) CHARACTER*1
41               Indicates how the vectors which define the  elementary  reflec‐
42               tors are stored:
43               = 'C': Columnwise
44               = 'R': Rowwise
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46       M       (input) INTEGER
47               The number of rows of the matrix C.
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49       N       (input) INTEGER
50               The number of columns of the matrix C.
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52       K       (input) INTEGER
53               The  order  of the matrix T (= the number of elementary reflec‐
54               tors whose product defines the block reflector).
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56       V       (input) DOUBLE PRECISION array, dimension
57               (LDV,K) if STOREV = 'C' (LDV,M) if STOREV = 'R' and SIDE =  'L'
58               (LDV,N)  if  STOREV = 'R' and SIDE = 'R' The matrix V. See fur‐
59               ther details.
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61       LDV     (input) INTEGER
62               The leading dimension of the array V.  If STOREV = 'C' and SIDE
63               =  'L', LDV >= max(1,M); if STOREV = 'C' and SIDE = 'R', LDV >=
64               max(1,N); if STOREV = 'R', LDV >= K.
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66       T       (input) DOUBLE PRECISION array, dimension (LDT,K)
67               The triangular k by k matrix T in  the  representation  of  the
68               block reflector.
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70       LDT     (input) INTEGER
71               The leading dimension of the array T. LDT >= K.
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73       C       (input/output) DOUBLE PRECISION array, dimension (LDC,N)
74               On  entry,  the  m by n matrix C.  On exit, C is overwritten by
75               H*C or H'*C or C*H or C*H'.
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77       LDC     (input) INTEGER
78               The leading dimension of the array C. LDA >= max(1,M).
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80       WORK    (workspace) DOUBLE PRECISION array, dimension (LDWORK,K)
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82       LDWORK  (input) INTEGER
83               The leading dimension of the array WORK.  If SIDE = 'L', LDWORK
84               >= max(1,N); if SIDE = 'R', LDWORK >= max(1,M).
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88 LAPACK auxiliary routine (versionNo3v.e2m)ber 2008                       DLARFB(1)
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