# dsdot.f (3) - Linux Manuals

dsdot.f -

## SYNOPSIS

### Functions/Subroutines

DOUBLE PRECISION function dsdot (N, SX, INCX, SY, INCY)
DSDOT

## Function/Subroutine Documentation

### DOUBLE PRECISION function dsdot (integerN, real, dimension(*)SX, integerINCX, real, dimension(*)SY, integerINCY)

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:

N

```          N is INTEGER
number of elements in input vector(s)
```

SX

```          SX is REAL array, dimension(N)
single precision vector with N elements
```

INCX

```          INCX is INTEGER
storage spacing between elements of SX
```

SY

```          SY is REAL array, dimension(N)
single precision vector with N elements
```

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.

Date:

November 2011

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)
```

Definition at line 120 of file dsdot.f.

## Author

Generated automatically by Doxygen for LAPACK from the source code.