# clarf.f - Man Page

## Synopsis

### Functions/Subroutines

subroutine **clarf** (SIDE, M, **N**, V, INCV, TAU, C, LDC, WORK)**CLARF** applies an elementary reflector to a general rectangular matrix.

## Function/Subroutine Documentation

### subroutine clarf (character SIDE, integer M, integer N, complex, dimension( * ) V, integer INCV, complex TAU, complex, dimension( ldc, * ) C, integer LDC, complex, dimension( * ) WORK)

**CLARF** applies an elementary reflector to a general rectangular matrix.

**Purpose:**

CLARF applies a complex elementary reflector H to a complex M-by-N matrix C, from either the left or the right. H is represented in the form H = I - tau * v * v**H where tau is a complex scalar and v is a complex vector. If tau = 0, then H is taken to be the unit matrix. To apply H**H (the conjugate transpose of H), supply conjg(tau) instead tau.

**Parameters:***SIDE*SIDE is CHARACTER*1 = 'L': form H * C = 'R': form C * H

*M*M is INTEGER The number of rows of the matrix C.

*N*N is INTEGER The number of columns of the matrix C.

*V*V is COMPLEX array, dimension (1 + (M-1)*abs(INCV)) if SIDE = 'L' or (1 + (N-1)*abs(INCV)) if SIDE = 'R' The vector v in the representation of H. V is not used if TAU = 0.

*INCV*INCV is INTEGER The increment between elements of v. INCV <> 0.

*TAU*TAU is COMPLEX The value tau in the representation of H.

*C*C is COMPLEX array, dimension (LDC,N) On entry, the M-by-N matrix C. On exit, C is overwritten by the matrix H * C if SIDE = 'L', or C * H if SIDE = 'R'.

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

*WORK*WORK is COMPLEX array, dimension (N) if SIDE = 'L' or (M) if SIDE = 'R'

**Author:**Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

**Date:**December 2016

Definition at line 130 of file clarf.f.

## Author

Generated automatically by Doxygen for LAPACK from the source code.

## Referenced By

The man page clarf(3) is an alias of clarf.f(3).

Tue Nov 14 2017 Version 3.8.0 LAPACK