---
name: "sdsdot.f"
section: "3"
platform: "linux"
package: "lapack-doc"
version: "3.12.1-2"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/sdsdot.f"
---

# sdsdot.f(3)

## NAME

BLAS/SRC/sdsdot.f

## SYNOPSIS

### Functions/Subroutines

real function **sdsdot** (n, sb, sx, incx, sy, incy)\
 **SDSDOT**

## Function/Subroutine Documentation

### real function sdsdot (integer n, real sb, real, dimension(\*) sx, integer incx, real, dimension(\*) sy, integer incy)

**SDSDOT**

**Purpose:**

```
!>
!>   Compute the inner product of two vectors with extended
!>   precision accumulation.
!>
!>   Returns S.P. result with dot product accumulated in D.P.
!>   SDSDOT = SB + 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)
!>
```

*SB*

```
!>          SB is REAL
!>          single precision scalar to be added to inner product
!>
```

*SX*

```
!>          SX is REAL array, dimension ( 1 + ( N - 1 )*abs( INCX ) )
!>          single precision vector with N elements
!>
```

*INCX*

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

*SY*

```
!>          SY is REAL array, dimension ( 1 + ( N - 1 )*abs( INCX ) )
!>          single precision vector with N elements
!>
```

*INCY*

```
!>          INCY is INTEGER
!>          storage spacing between elements of SY
!>
```

**Author**

Lawson, C. L., (JPL), Hanson, R. J., (SNLA),

Kincaid, D. R., (U. of Texas), Krogh, F. T., (JPL)

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
!>    890531  Changed all specific intrinsics to generic.  (WRB)
!>    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 coding style
!>
```

Definition at line **112** of file **sdsdot.f**.

## Author

Generated automatically by Doxygen for LAPACK from the source code.