LAPACK 3.12.0
LAPACK: Linear Algebra PACKage
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◆ dsdot()

double precision function dsdot ( integer n,
real, dimension(*) sx,
integer incx,
real, dimension(*) sy,
integer incy )

DSDOT

Purpose:
!>
!> 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.
!> 
Parameters
[in]N
!>          N is INTEGER
!>         number of elements in input vector(s)
!> 
[in]SX
!>          SX is REAL array, dimension(N)
!>         single precision vector with N elements
!> 
[in]INCX
!>          INCX is INTEGER
!>          storage spacing between elements of SX
!> 
[in]SY
!>          SY is REAL array, dimension(N)
!>         single precision vector with N elements
!> 
[in]INCY
!>          INCY is INTEGER
!>         storage spacing between elements of SY
!> 
Returns
DSDOT
!>          DSDOT is DOUBLE PRECISION
!>         DSDOT  double precision dot product (zero if N.LE.0)
!> 
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Further Details:
!> 
References:
!>
!>
!>  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)
!>