DQDOTI(3)

SYNOPSIS
DOUBLE PRECISION FUNCTION DQDOTI (N, DB, QC, DX, INCX, DY, INCY)

NAME
dqdoti - Compute the inner product of two vectors with extended precision accumulation and result.

LIBRARY
SLATEC

CATEGORY
D1A4

TYPE
DOUBLE PRECISION (DQDOTI-D)

KEYWORDS
DOT PRODUCT, INNER PRODUCT

AUTHOR
Lawson, C. L., (JPL) Hanson, R. J., (SNLA) Kincaid, D. R., (U. of Texas) Krogh, F. T., (JPL)

DESCRIPTION
B L A S Subprogram Description of parameters --Input-- N number of elements in input vector(s) DB double precision scalar to be added to inner product QC extended precision scalar to be added DX double precision vector with N elements INCX storage spacing between elements of DX DY double precision vector with N elements INCY storage spacing between elements of DY --Output-- DQDOTI double precision result QC extended precision result D.P. dot product with extended precision accumulation (and result) QC and DQDOTI are set = DB + sum for I = 0 to N-1 of DX(LX+I*INCX) * DY(LY+I*INCY), where QC is an extended precision result which can be used as input to DQDOTA, and LX = 1 if INCX .GE. 0, else LX = (-INCX)*N, and LY is defined in a similar way using INCY. The MP package by Richard P. Brent is used for the extended precision arithmetic. Fred T. Krogh, JPL, 1977, June 1 The common block for the MP package is named MPCOM. If local variable I1 is zero, DQDOTI calls MPBLAS to initialize the MP package and reset I1 to 1. The argument QC(*), and the local variables QX and QY are INTEGER arrays of size 30. See the comments in the routine MPBLAS for the reason for this choice.

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.

ROUTINES CALLED
MPADD, MPBLAS, MPCDM, MPCMD, MPMUL

COMMON BLOCKS
MPCOM

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)
920501 Reformatted the REFERENCES section. (WRB)
930124 Increased Array sizes for SUN -r8. (RWC)