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Commit | Line | Data |
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da0e9ce3 | 1 | FUNCTION PHOAN2(X,Y) |
2 | C.---------------------------------------------------------------------- | |
3 | C. | |
4 | C. PHOTOS: PHOton radiation in decays calculation of ANgle '2' | |
5 | C. | |
6 | C. Purpose: Calculate angle from X and Y | |
7 | C. | |
8 | C. Input Parameters: X, Y | |
9 | C. | |
10 | C. Output Parameter: Function value | |
11 | C. | |
12 | C. Author(s): S. Jadach Created at: 01/01/89 | |
13 | C. B. van Eijk Last Update: 02/01/90 | |
14 | C. | |
15 | C.---------------------------------------------------------------------- | |
16 | IMPLICIT NONE | |
17 | DOUBLE PRECISION PHOAN2 | |
18 | REAL*8 X,Y | |
19 | REAL*8 PI,TWOPI | |
20 | COMMON/PHPICO/PI,TWOPI | |
21 | IF (ABS(Y).LT.ABS(X)) THEN | |
22 | PHOAN2=ATAN(ABS(Y/X)) | |
23 | IF (X.LE.0.D0) PHOAN2=PI-PHOAN2 | |
24 | ELSE | |
25 | PHOAN2=ACOS(X/SQRT(X**2+Y**2)) | |
26 | ENDIF | |
27 | RETURN | |
28 | END |