.TH "dlarfg.f" 3 "Sun May 26 2013" "Version 3.4.1" "LAPACK" \" -*- nroff -*- .ad l .nh .SH NAME dlarfg.f \- .SH SYNOPSIS .br .PP .SS "Functions/Subroutines" .in +1c .ti -1c .RI "subroutine \fBdlarfg\fP (N, ALPHA, X, INCX, TAU)" .br .RI "\fI\fBDLARFG\fP \fP" .in -1c .SH "Function/Subroutine Documentation" .PP .SS "subroutine dlarfg (integerN, double precisionALPHA, double precision, dimension( * )X, integerINCX, double precisionTAU)" .PP \fBDLARFG\fP .PP \fBPurpose: \fP .RS 4 .PP .nf DLARFG 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 DOUBLE PRECISION On entry, the value alpha. On exit, it is overwritten with the value beta. .fi .PP .br \fIX\fP .PP .nf X is DOUBLE PRECISION 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 DOUBLE PRECISION 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 November 2011 .RE .PP .PP Definition at line 107 of file dlarfg\&.f\&. .SH "Author" .PP Generated automatically by Doxygen for LAPACK from the source code\&.