NAME¶

DSDOT - accumulation and result

SYNOPSIS¶

DOUBLE PRECISION

FUNCTION DSDOT(N,SX,INCX,SY,INCY)

INTEGER INCX,INCY,N REAL SX(*),SY(*)

PURPOSE¶

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.

ARGUMENTS¶

N (input) INTEGER

number of elements in input vector(s)

SX (input) REAL array, dimension(N)

single precision vector with N elements

INCX (input) INTEGER

storage spacing between elements of SX

SY (input) REAL array, dimension(N)

single precision vector with N elements

INCY (input) INTEGER

storage spacing between elements of SY

DSDOT (output) DOUBLE PRECISION

DSDOT double precision dot product (zero if N.LE.0)

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)