kopia lustrzana https://github.com/Dsplib/libdspl-2.0
173 wiersze
4.1 KiB
Fortran
173 wiersze
4.1 KiB
Fortran
*> \brief \b DSDOT
|
|
*
|
|
* =========== DOCUMENTATION ===========
|
|
*
|
|
* Online html documentation available at
|
|
* http://www.netlib.org/lapack/explore-html/
|
|
*
|
|
* Definition:
|
|
* ===========
|
|
*
|
|
* DOUBLE PRECISION FUNCTION DSDOT(N,SX,INCX,SY,INCY)
|
|
*
|
|
* .. Scalar Arguments ..
|
|
* INTEGER INCX,INCY,N
|
|
* ..
|
|
* .. Array Arguments ..
|
|
* REAL SX(*),SY(*)
|
|
* ..
|
|
*
|
|
* AUTHORS
|
|
* =======
|
|
* Lawson, C. L., (JPL), Hanson, R. J., (SNLA),
|
|
* Kincaid, D. R., (U. of Texas), Krogh, F. T., (JPL)
|
|
*
|
|
*
|
|
*> \par Purpose:
|
|
* =============
|
|
*>
|
|
*> \verbatim
|
|
*>
|
|
*> Compute the inner product of two vectors with extended
|
|
*> precision accumulation and result.
|
|
*>
|
|
*> Returns D.P. dot product accumulated in D.P., for S.P. SX and SY
|
|
*> DSDOT = sum for I = 0 to N-1 of SX(LX+I*INCX) * SY(LY+I*INCY),
|
|
*> where LX = 1 if INCX .GE. 0, else LX = 1+(1-N)*INCX, and LY is
|
|
*> defined in a similar way using INCY.
|
|
*> \endverbatim
|
|
*
|
|
* Arguments:
|
|
* ==========
|
|
*
|
|
*> \param[in] N
|
|
*> \verbatim
|
|
*> N is INTEGER
|
|
*> number of elements in input vector(s)
|
|
*> \endverbatim
|
|
*>
|
|
*> \param[in] SX
|
|
*> \verbatim
|
|
*> SX is REAL array, dimension(N)
|
|
*> single precision vector with N elements
|
|
*> \endverbatim
|
|
*>
|
|
*> \param[in] INCX
|
|
*> \verbatim
|
|
*> INCX is INTEGER
|
|
*> storage spacing between elements of SX
|
|
*> \endverbatim
|
|
*>
|
|
*> \param[in] SY
|
|
*> \verbatim
|
|
*> SY is REAL array, dimension(N)
|
|
*> single precision vector with N elements
|
|
*> \endverbatim
|
|
*>
|
|
*> \param[in] INCY
|
|
*> \verbatim
|
|
*> INCY is INTEGER
|
|
*> storage spacing between elements of SY
|
|
*> \endverbatim
|
|
*>
|
|
*> \result DSDOT
|
|
*> \verbatim
|
|
*> DSDOT is DOUBLE PRECISION
|
|
*> DSDOT double precision dot product (zero if N.LE.0)
|
|
*> \endverbatim
|
|
*
|
|
* Authors:
|
|
* ========
|
|
*
|
|
*> \author Univ. of Tennessee
|
|
*> \author Univ. of California Berkeley
|
|
*> \author Univ. of Colorado Denver
|
|
*> \author NAG Ltd.
|
|
*
|
|
*> \date December 2016
|
|
*
|
|
*> \ingroup double_blas_level1
|
|
*
|
|
*> \par Further Details:
|
|
* =====================
|
|
*>
|
|
*> \verbatim
|
|
*> \endverbatim
|
|
*
|
|
*> \par References:
|
|
* ================
|
|
*>
|
|
*> \verbatim
|
|
*>
|
|
*>
|
|
*> C. L. Lawson, R. J. Hanson, D. R. Kincaid and F. T.
|
|
*> Krogh, Basic linear algebra subprograms for Fortran
|
|
*> usage, Algorithm No. 539, Transactions on Mathematical
|
|
*> Software 5, 3 (September 1979), pp. 308-323.
|
|
*>
|
|
*> REVISION HISTORY (YYMMDD)
|
|
*>
|
|
*> 791001 DATE WRITTEN
|
|
*> 890831 Modified array declarations. (WRB)
|
|
*> 890831 REVISION DATE from Version 3.2
|
|
*> 891214 Prologue converted to Version 4.0 format. (BAB)
|
|
*> 920310 Corrected definition of LX in DESCRIPTION. (WRB)
|
|
*> 920501 Reformatted the REFERENCES section. (WRB)
|
|
*> 070118 Reformat to LAPACK style (JL)
|
|
*> \endverbatim
|
|
*>
|
|
* =====================================================================
|
|
DOUBLE PRECISION FUNCTION DSDOT(N,SX,INCX,SY,INCY)
|
|
*
|
|
* -- Reference BLAS level1 routine (version 3.7.0) --
|
|
* -- Reference BLAS is a software package provided by Univ. of Tennessee, --
|
|
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
|
|
* December 2016
|
|
*
|
|
* .. Scalar Arguments ..
|
|
INTEGER INCX,INCY,N
|
|
* ..
|
|
* .. Array Arguments ..
|
|
REAL SX(*),SY(*)
|
|
* ..
|
|
*
|
|
* Authors:
|
|
* ========
|
|
* Lawson, C. L., (JPL), Hanson, R. J., (SNLA),
|
|
* Kincaid, D. R., (U. of Texas), Krogh, F. T., (JPL)
|
|
*
|
|
* =====================================================================
|
|
*
|
|
* .. Local Scalars ..
|
|
INTEGER I,KX,KY,NS
|
|
* ..
|
|
* .. Intrinsic Functions ..
|
|
INTRINSIC DBLE
|
|
* ..
|
|
DSDOT = 0.0D0
|
|
IF (N.LE.0) RETURN
|
|
IF (INCX.EQ.INCY .AND. INCX.GT.0) THEN
|
|
*
|
|
* Code for equal, positive, non-unit increments.
|
|
*
|
|
NS = N*INCX
|
|
DO I = 1,NS,INCX
|
|
DSDOT = DSDOT + DBLE(SX(I))*DBLE(SY(I))
|
|
END DO
|
|
ELSE
|
|
*
|
|
* Code for unequal or nonpositive increments.
|
|
*
|
|
KX = 1
|
|
KY = 1
|
|
IF (INCX.LT.0) KX = 1 + (1-N)*INCX
|
|
IF (INCY.LT.0) KY = 1 + (1-N)*INCY
|
|
DO I = 1,N
|
|
DSDOT = DSDOT + DBLE(SX(KX))*DBLE(SY(KY))
|
|
KX = KX + INCX
|
|
KY = KY + INCY
|
|
END DO
|
|
END IF
|
|
RETURN
|
|
END
|