.TH "zlarfb.f" 3 "Wed Oct 15 2014" "Version 3.4.2" "LAPACK" \" -*- nroff -*- .ad l .nh .SH NAME zlarfb.f \- .SH SYNOPSIS .br .PP .SS "Functions/Subroutines" .in +1c .ti -1c .RI "subroutine \fBzlarfb\fP (SIDE, TRANS, DIRECT, STOREV, M, N, K, V, LDV, T, LDT, C, LDC, WORK, LDWORK)" .br .RI "\fI\fBZLARFB\fP applies a block reflector or its conjugate-transpose to a general rectangular matrix\&. \fP" .in -1c .SH "Function/Subroutine Documentation" .PP .SS "subroutine zlarfb (characterSIDE, characterTRANS, characterDIRECT, characterSTOREV, integerM, integerN, integerK, complex*16, dimension( ldv, * )V, integerLDV, complex*16, dimension( ldt, * )T, integerLDT, complex*16, dimension( ldc, * )C, integerLDC, complex*16, dimension( ldwork, * )WORK, integerLDWORK)" .PP \fBZLARFB\fP applies a block reflector or its conjugate-transpose to a general rectangular matrix\&. .PP \fBPurpose: \fP .RS 4 .PP .nf ZLARFB applies a complex block reflector H or its transpose H**H to a complex M-by-N matrix C, from either the left or the right. .fi .PP .RE .PP \fBParameters:\fP .RS 4 \fISIDE\fP .PP .nf SIDE is CHARACTER*1 = 'L': apply H or H**H from the Left = 'R': apply H or H**H from the Right .fi .PP .br \fITRANS\fP .PP .nf TRANS is CHARACTER*1 = 'N': apply H (No transpose) = 'C': apply H**H (Conjugate transpose) .fi .PP .br \fIDIRECT\fP .PP .nf DIRECT is CHARACTER*1 Indicates how H is formed from a product of elementary reflectors = 'F': H = H(1) H(2) . . . H(k) (Forward) = 'B': H = H(k) . . . H(2) H(1) (Backward) .fi .PP .br \fISTOREV\fP .PP .nf STOREV is CHARACTER*1 Indicates how the vectors which define the elementary reflectors are stored: = 'C': Columnwise = 'R': Rowwise .fi .PP .br \fIM\fP .PP .nf M is INTEGER The number of rows of the matrix C. .fi .PP .br \fIN\fP .PP .nf N is INTEGER The number of columns of the matrix C. .fi .PP .br \fIK\fP .PP .nf K is INTEGER The order of the matrix T (= the number of elementary reflectors whose product defines the block reflector). .fi .PP .br \fIV\fP .PP .nf V is COMPLEX*16 array, dimension (LDV,K) if STOREV = 'C' (LDV,M) if STOREV = 'R' and SIDE = 'L' (LDV,N) if STOREV = 'R' and SIDE = 'R' See Further Details. .fi .PP .br \fILDV\fP .PP .nf LDV is INTEGER The leading dimension of the array V. If STOREV = 'C' and SIDE = 'L', LDV >= max(1,M); if STOREV = 'C' and SIDE = 'R', LDV >= max(1,N); if STOREV = 'R', LDV >= K. .fi .PP .br \fIT\fP .PP .nf T is COMPLEX*16 array, dimension (LDT,K) The triangular K-by-K matrix T in the representation of the block reflector. .fi .PP .br \fILDT\fP .PP .nf LDT is INTEGER The leading dimension of the array T. LDT >= K. .fi .PP .br \fIC\fP .PP .nf C is COMPLEX*16 array, dimension (LDC,N) On entry, the M-by-N matrix C. On exit, C is overwritten by H*C or H**H*C or C*H or C*H**H. .fi .PP .br \fILDC\fP .PP .nf LDC is INTEGER The leading dimension of the array C. LDC >= max(1,M). .fi .PP .br \fIWORK\fP .PP .nf WORK is COMPLEX*16 array, dimension (LDWORK,K) .fi .PP .br \fILDWORK\fP .PP .nf LDWORK is INTEGER The leading dimension of the array WORK. If SIDE = 'L', LDWORK >= max(1,N); if SIDE = 'R', LDWORK >= max(1,M). .fi .PP .RE .PP \fBAuthor:\fP .RS 4 Univ\&. of Tennessee .PP Univ\&. of California Berkeley .PP Univ\&. of Colorado Denver .PP NAG Ltd\&. .RE .PP \fBDate:\fP .RS 4 June 2013 .RE .PP \fBFurther Details: \fP .RS 4 .PP .nf The shape of the matrix V and the storage of the vectors which define the H(i) is best illustrated by the following example with n = 5 and k = 3. The elements equal to 1 are not stored; the corresponding array elements are modified but restored on exit. The rest of the array is not used. DIRECT = 'F' and STOREV = 'C': DIRECT = 'F' and STOREV = 'R': V = ( 1 ) V = ( 1 v1 v1 v1 v1 ) ( v1 1 ) ( 1 v2 v2 v2 ) ( v1 v2 1 ) ( 1 v3 v3 ) ( v1 v2 v3 ) ( v1 v2 v3 ) DIRECT = 'B' and STOREV = 'C': DIRECT = 'B' and STOREV = 'R': V = ( v1 v2 v3 ) V = ( v1 v1 1 ) ( v1 v2 v3 ) ( v2 v2 v2 1 ) ( 1 v2 v3 ) ( v3 v3 v3 v3 1 ) ( 1 v3 ) ( 1 ) .fi .PP .RE .PP .PP Definition at line 195 of file zlarfb\&.f\&. .SH "Author" .PP Generated automatically by Doxygen for LAPACK from the source code\&.