|
SUBROUTINE SLA_WWADDW( N, X, Y, W )
* * -- LAPACK routine (version 3.2.2) -- * -- Contributed by James Demmel, Deaglan Halligan, Yozo Hida and -- * -- Jason Riedy of Univ. of California Berkeley. -- * -- June 2010 -- * * -- LAPACK is a software package provided by Univ. of Tennessee, -- * -- Univ. of California Berkeley and NAG Ltd. -- * IMPLICIT NONE * .. * .. Scalar Arguments .. INTEGER N * .. * .. Array Arguments .. REAL X( * ), Y( * ), W( * ) * .. * * Purpose * ======= * * SLA_WWADDW adds a vector W into a doubled-single vector (X, Y). * * This works for all extant IBM's hex and binary floating point * arithmetics, but not for decimal. * * Arguments * ========= * * N (input) INTEGER * The length of vectors X, Y, and W. * * X (input/output) REAL array, dimension (N) * The first part of the doubled-single accumulation vector. * * Y (input/output) REAL array, dimension (N) * The second part of the doubled-single accumulation vector. * * W (input) REAL array, dimension (N) * The vector to be added. * * ===================================================================== * * .. Local Scalars .. REAL S INTEGER I * .. * .. Executable Statements .. * DO 10 I = 1, N S = X(I) + W(I) S = (S + S) - S Y(I) = ((X(I) - S) + W(I)) + Y(I) X(I) = S 10 CONTINUE RETURN END |