wcancel_i(3PI) Sun Interval Performance Library wcancel_i(3PI)NAMEwcancel_i - Scaled cancellation.
DESCRIPTION
W = ALPHA * X .CANCEL. BETA * Y
The operation CANCEL, between two intervals A and B is defined as A
.CANCEL. B = [INF(A)-INF(B),SUP(A)-SUP(B)]
if (INF(A)-INF(B)) <= (SUP(A)-SUP(B)); Otherwise 0.
The routine WCANCEL_I scales the interval vector X by the interval
ALPHA and the interval vector Y by BETA, and stores the result of
scaled cancellation in the vector W. The routine returns immediately
if N is equal to zero.
SYNOPSIS
SUBROUTINE WCANCEL_I( X, Y, W [, ALPHA] [, BETA] )
INTERVAL, INTENT(IN) :: X(:), Y(:)
INTERVAL, INTENT(OUT) :: W(:)
INTERVAL, INTENT(IN), OPTIONAL :: ALPHA, BETA
where
X, Y and W have shape (N).
ARGUMENTS
X (input)
Array of DIMENSION N.
Unchanged on exit.
Y (input)
Array of DIMENSION N.
Unchanged on exit.
W (output)
Array of DIMENSION N.
On exit, W is overwritten by results of subroutine:
W = ALPHA * X .CANCEL. BETA * Y
ALPHA (input)
On entry, ALPHA specifies the scalar ALPHA.
Default value is ALPHA = [1,1].
Unchanged on exit.
BETA (input)
On entry, BETA specifies the scalar BETA.
Default value is BETA = [0,0].
Unchanged on exit.
ERRORS
blas_error_alloc
X, Y or W is unallocated array
blas_error_shape
shape(X) /= shape(Y) /= shape(W)
6 Mar 2009 wcancel_i(3PI)
