Note: this is a BLAS routine and is not in libslatec.a
*DECK DSDOT DOUBLE PRECISION FUNCTION DSDOT (N, SX, INCX, SY, INCY) C***BEGIN PROLOGUE DSDOT C***PURPOSE Compute the inner product of two vectors with extended C precision accumulation and result. C***LIBRARY SLATEC (BLAS) C***CATEGORY D1A4 C***TYPE DOUBLE PRECISION (DSDOT-D, DCDOT-C) C***KEYWORDS BLAS, COMPLEX VECTORS, DOT PRODUCT, INNER PRODUCT, C LINEAR ALGEBRA, VECTOR C***AUTHOR Lawson, C. L., (JPL) C Hanson, R. J., (SNLA) C Kincaid, D. R., (U. of Texas) C Krogh, F. T., (JPL) C***DESCRIPTION C C B L A S Subprogram C Description of Parameters C C --Input-- C N number of elements in input vector(s) C SX single precision vector with N elements C INCX storage spacing between elements of SX C SY single precision vector with N elements C INCY storage spacing between elements of SY C C --Output-- C DSDOT double precision dot product (zero if N.LE.0) C C Returns D.P. dot product accumulated in D.P., for S.P. SX and SY C DSDOT = sum for I = 0 to N-1 of SX(LX+I*INCX) * SY(LY+I*INCY), C where LX = 1 if INCX .GE. 0, else LX = 1+(1-N)*INCX, and LY is C defined in a similar way using INCY. C C***REFERENCES C. L. Lawson, R. J. Hanson, D. R. Kincaid and F. T. C Krogh, Basic linear algebra subprograms for Fortran C usage, Algorithm No. 539, Transactions on Mathematical C Software 5, 3 (September 1979), pp. 308-323. C***ROUTINES CALLED (NONE) C***REVISION HISTORY (YYMMDD) C 791001 DATE WRITTEN C 890831 Modified array declarations. (WRB) C 890831 REVISION DATE from Version 3.2 C 891214 Prologue converted to Version 4.0 format. (BAB) C 920310 Corrected definition of LX in DESCRIPTION. (WRB) C 920501 Reformatted the REFERENCES section. (WRB) C***END PROLOGUE DSDOT