DSCAL(3) BLAS routine of NEC Numeric Library Collection DSCAL(3)
NAME
DSCAL - BLAS level one, scales a double precision vector
SYNOPSIS
SUBROUTINE DSCAL ( n, alpha, x, incx )
INTEGER n, incx
DOUBLE PRECISION alpha, x
DESCRIPTION
DSCAL scales a double precision vector with a double precision scalar.
DSCAL scales the vector x of length n and increment incx by the con-
stant a.
This routine performs the following vector operation:
x <-- alpha x
where alpha is a double precisoin scalar, and x is a double precision
vector.
ARGUMENTS
n INTEGER. (input)
Number of elements in the vector.
If n <= 0, this routine returns without computation.
alpha DOUBLE PRECISION scalar alpha. (input)
x DOUBLE PRECISION, (input and output)
Array of dimension (n-1) * |incx| + 1. Vector to be scaled.
incx INTEGER. (input)
Increment between elements of x.
If incx = 0, the results will be unpredictable.
NOTES
This routine is Level 1 Basic Linear Algebra Subprograms (Level 1
BLAS).
When working backward (incx < 0 or incy < 0), each routine starts at
the end of the vector and moves backward, as follows:
x(1-incx * (n-1)), x(1-incx * (n-2)), ..., x(1)
BLAS routine DSCAL(3)