#include "ESMF_LapackBlas.inc" !> \brief \b DROT ! ! =========== DOCUMENTATION =========== ! ! Online html documentation available at ! http://www.netlib.org/lapack/explore-html/ ! ! Definition: ! =========== ! ! SUBROUTINE DROT(N,DX,INCX,DY,INCY,C,S) ! ! .. Scalar Arguments .. ! DOUBLE PRECISION C,S ! INTEGER INCX,INCY,N ! .. ! .. Array Arguments .. ! DOUBLE PRECISION DX(*),DY(*) ! .. ! ! !> \par Purpose: ! ============= !> !> \verbatim !> !> DROT applies a plane rotation. !> \endverbatim ! ! Authors: ! ======== ! !> \author Univ. of Tennessee !> \author Univ. of California Berkeley !> \author Univ. of Colorado Denver !> \author NAG Ltd. ! !> \date November 2011 ! !> \ingroup double_blas_level1 ! !> \par Further Details: ! ===================== !> !> \verbatim !> !> jack dongarra, linpack, 3/11/78. !> modified 12/3/93, array(1) declarations changed to array(*) !> \endverbatim !> ! ===================================================================== SUBROUTINE DROT(N,DX,INCX,DY,INCY,C,S) ! ! -- Reference BLAS level1 routine (version 3.4.0) -- ! -- Reference BLAS is a software package provided by Univ. of Tennessee, -- ! -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- ! November 2011 ! ! .. Scalar Arguments .. DOUBLE PRECISION C,S INTEGER INCX,INCY,N ! .. ! .. Array Arguments .. DOUBLE PRECISION DX(*),DY(*) ! .. ! ! ===================================================================== ! ! .. Local Scalars .. DOUBLE PRECISION DTEMP INTEGER I,IX,IY ! .. IF (N.LE.0) RETURN IF (INCX.EQ.1 .AND. INCY.EQ.1) THEN ! ! code for both increments equal to 1 ! DO I = 1,N DTEMP = C*DX(I) + S*DY(I) DY(I) = C*DY(I) - S*DX(I) DX(I) = DTEMP END DO ELSE ! ! code for unequal increments or equal increments not equal ! to 1 ! IX = 1 IY = 1 IF (INCX.LT.0) IX = (-N+1)*INCX + 1 IF (INCY.LT.0) IY = (-N+1)*INCY + 1 DO I = 1,N DTEMP = C*DX(IX) + S*DY(IY) DY(IY) = C*DY(IY) - S*DX(IX) DX(IX) = DTEMP IX = IX + INCX IY = IY + INCY END DO END IF RETURN END