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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)
      !>