Math Vector Library
Programming Reference Manual Fortran
Version 1.0 DD-00002-110

6.19 vatanpi - Vector arctangent tan-1(x)/π

subroutine vatanpi (n, y, incy, x, incx);
subroutine vatanpif(n, y, incy, x, incx);

Given an input vector x  and a result vector y  , this function computes:

y= tan -1(x)/π

6.19.1 Parameters

N - INTEGER

ENTRY: Number of elements of x  and y  .
CONSTRAINT: n ≥1  .

Y - ARRAY OF REAL

EXIT: Result vector y  .
CONSTRAINT: Must contain n× incy  elements.
CONSTRAINT: Must not overlap with array x  .

INCY - INTEGER

ENTRY: Stride for the vector y  .
CONSTRAINT: incy> 0  .

X - ARRAY OF REAL

ENTRY: Input vector x  .
CONSTRAINT: Must contain n× incx  elements.
CONSTRAINT: Must not overlap with array y  .

INCX - INTEGER

ENTRY: Stride for the vector x  .
CONSTRAINT: incx> 0  .