HP MLIB User's Guide Vol. 2 7th Ed.

Chapter 12 VMATH 841
The arccosine of the elements of a vector vsacos, vdacos
Name vsacos, vdacos
The arccosine of the elements of a vector
Purpose vsacos and vdacos calculate the arccosine function of vector elements:
y(i) = acos(a(i)), for 1 <= i <= n
Usage The Fortran include file math.fi declares interfaces for these subroutines,
suitable for both VMATH and VMATH8. The interfaces are compatible with
Intel’s MKL VML (Vector Math Library).
SUBROUTINE vsacos(n, a, y)
INTEGER, INTENT(IN) :: n
REAL (KIND=4), DIMENSION(n), INTENT(IN) :: a
REAL (KIND=4), DIMENSION(n), INTENT(OUT):: y
SUBROUTINE vdacos(n, a, y)
INTEGER, INTENT(IN) :: n
REAL (KIND=8), DIMENSION(n), INTENT(IN) :: a
REAL (KIND=8), DIMENSION(n), INTENT(OUT):: y
Input n Number of elements to be calculated.
a Array of length at least n, specifying the input vector.
Output y Array of length at least n specifying the output vector.