You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
141 lines
2.9 KiB
141 lines
2.9 KiB
2 years ago
|
*> \brief \b SSCAL
|
||
|
|
*
|
||
|
|
* =========== DOCUMENTATION ===========
|
||
|
|
*
|
||
|
|
* Online html documentation available at
|
||
|
|
* http://www.netlib.org/lapack/explore-html/
|
||
|
|
*
|
||
|
|
* Definition:
|
||
|
|
* ===========
|
||
|
|
*
|
||
|
|
* SUBROUTINE SSCAL(N,SA,SX,INCX)
|
||
|
|
*
|
||
|
|
* .. Scalar Arguments ..
|
||
|
|
* REAL SA
|
||
|
|
* INTEGER INCX,N
|
||
|
|
* ..
|
||
|
|
* .. Array Arguments ..
|
||
|
|
* REAL SX(*)
|
||
|
|
* ..
|
||
|
|
*
|
||
|
|
*
|
||
|
|
*> \par Purpose:
|
||
|
|
* =============
|
||
|
|
*>
|
||
|
|
*> \verbatim
|
||
|
|
*>
|
||
|
|
*> SSCAL scales a vector by a constant.
|
||
|
|
*> uses unrolled loops for increment equal to 1.
|
||
|
|
*> \endverbatim
|
||
|
|
*
|
||
|
|
* Arguments:
|
||
|
|
* ==========
|
||
|
|
*
|
||
|
|
*> \param[in] N
|
||
|
|
*> \verbatim
|
||
|
|
*> N is INTEGER
|
||
|
|
*> number of elements in input vector(s)
|
||
|
|
*> \endverbatim
|
||
|
|
*>
|
||
|
|
*> \param[in] SA
|
||
|
|
*> \verbatim
|
||
|
|
*> SA is REAL
|
||
|
|
*> On entry, SA specifies the scalar alpha.
|
||
|
|
*> \endverbatim
|
||
|
|
*>
|
||
|
|
*> \param[in,out] SX
|
||
|
|
*> \verbatim
|
||
|
|
*> SX is REAL array, dimension ( 1 + ( N - 1 )*abs( INCX ) )
|
||
|
|
*> \endverbatim
|
||
|
|
*>
|
||
|
|
*> \param[in] INCX
|
||
|
|
*> \verbatim
|
||
|
|
*> INCX is INTEGER
|
||
|
|
*> storage spacing between elements of SX
|
||
|
|
*> \endverbatim
|
||
|
|
*
|
||
|
|
* Authors:
|
||
|
|
* ========
|
||
|
|
*
|
||
|
|
*> \author Univ. of Tennessee
|
||
|
|
*> \author Univ. of California Berkeley
|
||
|
|
*> \author Univ. of Colorado Denver
|
||
|
|
*> \author NAG Ltd.
|
||
|
|
*
|
||
|
|
*> \ingroup single_blas_level1
|
||
|
|
*
|
||
|
|
*> \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
|
||
|
|
*>
|
||
|
|
* =====================================================================
|
||
|
|
SUBROUTINE SSCAL(N,SA,SX,INCX)
|
||
|
|
*
|
||
|
|
* -- Reference BLAS level1 routine --
|
||
|
|
* -- Reference BLAS is a software package provided by Univ. of Tennessee, --
|
||
|
|
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
|
||
|
|
*
|
||
|
|
* .. Scalar Arguments ..
|
||
|
|
REAL SA
|
||
|
|
INTEGER INCX,N
|
||
|
|
* ..
|
||
|
|
* .. Array Arguments ..
|
||
|
|
REAL SX(*)
|
||
|
|
* ..
|
||
|
|
*
|
||
|
|
* =====================================================================
|
||
|
|
*
|
||
|
|
* .. Local Scalars ..
|
||
|
|
INTEGER I,M,MP1,NINCX
|
||
|
|
* ..
|
||
|
|
* .. Parameters ..
|
||
|
|
REAL ONE
|
||
|
|
PARAMETER (ONE=1.0E+0)
|
||
|
|
* ..
|
||
|
|
* .. Intrinsic Functions ..
|
||
|
|
INTRINSIC MOD
|
||
|
|
* ..
|
||
|
|
IF (N.LE.0 .OR. INCX.LE.0 .OR. SA.EQ.ONE) RETURN
|
||
|
|
IF (INCX.EQ.1) THEN
|
||
|
|
*
|
||
|
|
* code for increment equal to 1
|
||
|
|
*
|
||
|
|
*
|
||
|
|
* clean-up loop
|
||
|
|
*
|
||
|
|
M = MOD(N,5)
|
||
|
|
IF (M.NE.0) THEN
|
||
|
|
DO I = 1,M
|
||
|
|
SX(I) = SA*SX(I)
|
||
|
|
END DO
|
||
|
|
IF (N.LT.5) RETURN
|
||
|
|
END IF
|
||
|
|
MP1 = M + 1
|
||
|
|
DO I = MP1,N,5
|
||
|
|
SX(I) = SA*SX(I)
|
||
|
|
SX(I+1) = SA*SX(I+1)
|
||
|
|
SX(I+2) = SA*SX(I+2)
|
||
|
|
SX(I+3) = SA*SX(I+3)
|
||
|
|
SX(I+4) = SA*SX(I+4)
|
||
|
|
END DO
|
||
|
|
ELSE
|
||
|
|
*
|
||
|
|
* code for increment not equal to 1
|
||
|
|
*
|
||
|
|
NINCX = N*INCX
|
||
|
|
DO I = 1,NINCX,INCX
|
||
|
|
SX(I) = SA*SX(I)
|
||
|
|
END DO
|
||
|
|
END IF
|
||
|
|
RETURN
|
||
|
|
*
|
||
|
|
* End of SSCAL
|
||
|
|
*
|
||
|
|
END
|