Bugfix in AliPoints2Memory
[u/mrichter/AliRoot.git] / GEANT321 / cgpack / cgbfit.F
CommitLineData
fe4da5cc 1*
2* $Id$
3*
4* $Log$
5* Revision 1.1.1.1 1995/10/24 10:19:41 cernlib
6* Geant
7*
8*
9#include "geant321/pilot.h"
10*CMZ : 3.21/02 29/03/94 15.41.31 by S.Giani
11*-- Author :
12 SUBROUTINE CGBFIT(FACE,ABCD,NT)
13************************************************************************
14* *
15* Name: CGBFIT *
16* Author: E. Chernyaev Date: 15.03.89 *
17* Revised: S.Giani 1992 *
18* *
19* Function: Find all intersection points of face with plane *
20* *
21* References: none *
22* *
23* Input: FACE(*) - face *
24* ABCD(4) - plane *
25* *
26* Output: NT - number of intersections *
27* *
28* *
29************************************************************************
30#include "geant321/cggpar.inc"
31#include "geant321/cgcedg.inc"
32#include "geant321/cgdelt.inc"
33 REAL FACE(*),ABCD(4)
34#if !defined(CERNLIB_SINGLE)
35 DOUBLE PRECISION A,B,C,D
36#endif
37 INTEGER KCG(6)
38 DATA KCG/KCGX1,KCGY1,KCGZ1,KCGX2,KCGY2,KCGZ2/
39*-
40 ERROR = EEWOR
41 A = ABCD(1)
42 B = ABCD(2)
43 C = ABCD(3)
44 D = ABCD(4)
45* D1=0
46* D2=0
47 XDELT = FACE(KCGBB)*C - B*FACE(KCGCC)
48 YDELT = FACE(KCGCC)*A - C*FACE(KCGAA)
49 ZDELT = FACE(KCGAA)*B - A*FACE(KCGBB)
50 K = 1
51 IF (ABS(YDELT) .GT. ABS(XDELT)) K = 2
52 IF (ABS(ZDELT) .GT. ABS(DELTA(K))) K = 3
53 IF(ABS(DELTA(K)).LT.ERROR)RETURN
54 DD = 1./ABS(DELTA(K))
55 DELTA(1) = DELTA(1) * DD
56 DELTA(2) = DELTA(2) * DD
57 DELTA(3) = DELTA(3) * DD
58 KCG1 = KCG(K)
59 KCG2 = KCG(K+3)
60* F I N D I N T E R S E C T I O N S P O I N T S
61 J = LCGFAC - LCGEDG
62 NT = 0
63 NEDGE = FACE(KCGNE)
64 DO 600 NE=1,NEDGE
65 J = J + LCGEDG
66 D1 = A*FACE(J+KCGX1) + B*FACE(J+KCGY1) + C*FACE(J+KCGZ1) + D
67 D2 = A*FACE(J+KCGX2) + B*FACE(J+KCGY2) + C*FACE(J+KCGZ2) + D
68 IF (ABS(D1) .LE. ERROR) D1 = 0.
69 IF (ABS(D2) .LE. ERROR) D2 = 0.
70 IF (D1*D2 .GT. 0.) GOTO 600
71 NT = NT + 1
72 IF (D1.EQ.0. .AND. D2.EQ.0.) GOTO 500
73 IF (D1.LT.0. .OR. D2.GT.0.) TTT(2,NT) =-1.
74 IF (D1.GT.0. .OR. D2.LT.0.) TTT(2,NT) =+1.
75* D 1 O R D 2 I S N O T Z E R O
76 IF (NT .NE. 1) GOTO 400
77 XA = (D2*FACE(J+KCGX1)-D1*FACE(J+KCGX2)) / (D2 - D1)
78 YA = (D2*FACE(J+KCGY1)-D1*FACE(J+KCGY2)) / (D2 - D1)
79 ZA = (D2*FACE(J+KCGZ1)-D1*FACE(J+KCGZ2)) / (D2 - D1)
80 TTT(1,1) = 0.
81 GOTO 600
82 400 X = (D2*FACE(J+KCG1)-D1*FACE(J+KCG2)) / (D2 - D1)
83 TTT(1,NT) = (X - AA(K)) / DELTA(K)
84 GOTO 600
85* D 1 A N D D 2 B O T H A R E Z E R O
86 500 IF (NT .NE. 1) GOTO 510
87 XA = FACE(J+KCGX1)
88 YA = FACE(J+KCGY1)
89 ZA = FACE(J+KCGZ1)
90 TTT(1,1) = 0.
91 TTT(2,1) = 0.
92 GOTO 520
93 510 X = FACE(J+KCG1)
94 TTT(1,NT) = (X - AA(K)) / DELTA(K)
95 TTT(2,NT) = 0.
96 520 NT = NT + 1
97 X = FACE(J+KCG2)
98 TTT(1,NT) = (X - AA(K)) / DELTA(K)
99 TTT(2,NT) = 2.
100 IF (TTT(1,NT) .GT. TTT(1,NT-1)) GOTO 600
101 TTT(2,NT-1)= 2.
102 TTT(2,NT) = 0.
103 600 CONTINUE
104 RETURN
105 END