#include "ESMF_LapackBlas.inc" !> \brief \b IDAMAX ! ! =========== DOCUMENTATION =========== ! ! Online html documentation available at ! http://www.netlib.org/lapack/explore-html/ ! ! Definition: ! =========== ! ! INTEGER FUNCTION IDAMAX(N,DX,INCX) ! ! .. Scalar Arguments .. ! INTEGER INCX,N ! .. ! .. Array Arguments .. ! DOUBLE PRECISION DX(*) ! .. ! ! !> \par Purpose: ! ============= !> !> \verbatim !> !> IDAMAX finds the index of element having max. absolute value. !> \endverbatim ! ! Authors: ! ======== ! !> \author Univ. of Tennessee !> \author Univ. of California Berkeley !> \author Univ. of Colorado Denver !> \author NAG Ltd. ! !> \date November 2011 ! !> \ingroup aux_blas ! !> \par Further Details: ! ===================== !> !> \verbatim !> !> jack dongarra, linpack, 3/11/78. !> modified 3/93 to return if incx .le. 0. !> modified 12/3/93, array(1) declarations changed to array(*) !> \endverbatim !> ! ===================================================================== INTEGER FUNCTION IDAMAX(N,DX,INCX) ! ! -- 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 .. INTEGER INCX,N ! .. ! .. Array Arguments .. DOUBLE PRECISION DX(*) ! .. ! ! ===================================================================== ! ! .. Local Scalars .. DOUBLE PRECISION DMAX INTEGER I,IX ! .. ! .. Intrinsic Functions .. INTRINSIC DABS ! .. IDAMAX = 0 IF (N.LT.1 .OR. INCX.LE.0) RETURN IDAMAX = 1 IF (N.EQ.1) RETURN IF (INCX.EQ.1) THEN ! ! code for increment equal to 1 ! DMAX = DABS(DX(1)) DO I = 2,N IF (DABS(DX(I)).GT.DMAX) THEN IDAMAX = I DMAX = DABS(DX(I)) END IF END DO ELSE ! ! code for increment not equal to 1 ! IX = 1 DMAX = DABS(DX(1)) IX = IX + INCX DO I = 2,N IF (DABS(DX(IX)).GT.DMAX) THEN IDAMAX = I DMAX = DABS(DX(IX)) END IF IX = IX + INCX END DO END IF RETURN END