blob: e2528678b35eea43208bc0168798e82b197b15b1 (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
|
SUBROUTINE sla_VN (V, UV, VM)
*+
* - - -
* V N
* - - -
*
* Normalizes a 3-vector also giving the modulus (single precision)
*
* Given:
* V real(3) vector
*
* Returned:
* UV real(3) unit vector in direction of V
* VM real modulus of V
*
* If the modulus of V is zero, UV is set to zero as well
*
* P.T.Wallace Starlink 23 November 1995
*
* Copyright (C) 1995 Rutherford Appleton Laboratory
*-
IMPLICIT NONE
REAL V(3),UV(3),VM
INTEGER I
REAL W1,W2
* Modulus
W1=0.0
DO I=1,3
W2=V(I)
W1=W1+W2*W2
END DO
W1=SQRT(W1)
VM=W1
* Normalize the vector
IF (W1.LE.0.0) W1=1.0
DO I=1,3
UV(I)=V(I)/W1
END DO
END
|
