F118 Rotating a 3-Vector

Subroutine subprogram ROT rotates a 3-vector $(a$₁,a₂,a₃)

by a given angle $\theta$ around the z-axis.

Structure:

SUBROUTINE subprogram
User Entry Names: ROT
COMMON Block Names and Lengths: /SLATE/ 40

Usage:

    CALL ROT(A,TH,B)

A

( REAL) One-dimensional array of length 3, containing $(a$₁,a₂,a₃) .

TH

( REAL) Angle $\theta$ given in radians.

B

( REAL) One-dimensional array of length 3. On exit, B contains the components $(b$₁,b₂,b₃) of the rotated vector, i.e.

$b$₁=a₁cosθ-a₂sinθ

$b$₂=a₁sinθ+a₂cosθ

$b$₃=a₃ .

F121