clarfy.f

Section: LAPACK (3)
Updated: Tue Nov 14 2017
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clarfy.f

SYNOPSIS

Functions/Subroutines

subroutine clarfy (UPLO, N, V, INCV, TAU, C, LDC, WORK)
CLARFY

Function/Subroutine Documentation

subroutine clarfy (character UPLO, integer N, complex, dimension( * ) V, integer INCV, complex TAU, complex, dimension( ldc, * ) C, integer LDC, complex, dimension( * ) WORK)

CLARFY

Purpose:

CLARFY applies an elementary reflector, or Householder matrix, H,
to an n x n Hermitian matrix C, from both the left and the right.

H is represented in the form

H = I - tau * v * v'

where  tau  is a scalar and  v  is a vector.

If  tau  is  zero, then  H  is taken to be the unit matrix.

Parameters:

UPLO

UPLO is CHARACTER*1
Specifies whether the upper or lower triangular part of the
Hermitian matrix C is stored.
= 'U':  Upper triangle
= 'L':  Lower triangle

N

N is INTEGER
The number of rows and columns of the matrix C.  N >= 0.

V

V is COMPLEX array, dimension
(1 + (N-1)*abs(INCV))
The vector v as described above.

INCV

INCV is INTEGER
The increment between successive elements of v.  INCV must
not be zero.

TAU

TAU is COMPLEX
The value tau as described above.

C

C is COMPLEX array, dimension (LDC, N)
On entry, the matrix C.
On exit, C is overwritten by H * C * H'.

LDC

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

WORK

WORK is COMPLEX array, dimension (N)

Author:

Univ. of Tennessee

Univ. of California Berkeley