.TH "slarfg.f" 3 "Wed Oct 15 2014" "Version 3.4.2" "LAPACK" \" -*- nroff -*- .ad l .nh .SH NAME slarfg.f \- .SH SYNOPSIS .br .PP .SS "Functions/Subroutines" .in +1c .ti -1c .RI "subroutine \fBslarfg\fP (N, ALPHA, X, INCX, TAU)" .br .RI "\fI\fBSLARFG\fP generates an elementary reflector (Householder matrix)\&. \fP" .in -1c .SH "Function/Subroutine Documentation" .PP .SS "subroutine slarfg (integerN, realALPHA, real, dimension( * )X, integerINCX, realTAU)" .PP \fBSLARFG\fP generates an elementary reflector (Householder matrix)\&. .PP \fBPurpose: \fP .RS 4 .PP .nf SLARFG generates a real elementary reflector H of order n, such that H * ( alpha ) = ( beta ), H**T * H = I. ( x ) ( 0 ) where alpha and beta are scalars, and x is an (n-1)-element real vector. H is represented in the form H = I - tau * ( 1 ) * ( 1 v**T ) , ( v ) where tau is a real scalar and v is a real (n-1)-element vector. If the elements of x are all zero, then tau = 0 and H is taken to be the unit matrix. Otherwise 1 <= tau <= 2. .fi .PP .RE .PP \fBParameters:\fP .RS 4 \fIN\fP .PP .nf N is INTEGER The order of the elementary reflector. .fi .PP .br \fIALPHA\fP .PP .nf ALPHA is REAL On entry, the value alpha. On exit, it is overwritten with the value beta. .fi .PP .br \fIX\fP .PP .nf X is REAL array, dimension (1+(N-2)*abs(INCX)) On entry, the vector x. On exit, it is overwritten with the vector v. .fi .PP .br \fIINCX\fP .PP .nf INCX is INTEGER The increment between elements of X. INCX > 0. .fi .PP .br \fITAU\fP .PP .nf TAU is REAL The value tau. .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 September 2012 .RE .PP .PP Definition at line 107 of file slarfg\&.f\&. .SH "Author" .PP Generated automatically by Doxygen for LAPACK from the source code\&.