+++ /dev/null
-*
-* $Id$
-*
-* $Log$
-* Revision 1.1.1.1 1995/10/24 10:20:51 cernlib
-* Geant
-*
-*
-#include "geant321/pilot.h"
-*CMZ : 3.21/02 29/03/94 15.41.29 by S.Giani
-*-- Author :
- SUBROUTINE GNCONE(X,P,IACT,IFL,SNEXT,SNXT,SAFE)
-C. ******************************************************************
-C. * *
-C. * Compute distance to intersection with boundary surface of *
-C * volume CONE or CONS, from point X(1),X(2),X(3) inside *
-C * the volume along track with direction cosines X(4),X(5), *
-C * X(6) *
-C. * P (input) : volume parameters *
-C. * IACT (input) : action flag *
-C. * = 0 Compute SAFE only *
-C. * = 1 Compute SAFE, compute SNXT only if SAFE.LT.SNEXT *
-C. * = 2 Compute both SAFE and SNXT *
-C. * = 3 Compute SNXT only *
-C. * IFL (input) : 1 for CONE, 2 for PHI segmented CONE *
-C. * SNEXT (input) : see IACT = 1 *
-C. * SNXT (output) : distance to volume boundary along track *
-C. * SAFE (output) : not larger than scalar distance to *
-C. * volume boundaray *
-C. * Called by : GNEXT, GNOPCO, GTNEXT *
-C. * *
-C. * Authors : Michel Maire and Rolf Nierhaus 21-JUN-1990 *
-C. * *
-C. ******************************************************************
-C. * *
-C. * 'CONE' is a conical tube. It has 5 parameters : *
-C. * the half length in z, *
-C. * the inside and outside radii at the low z limit, *
-C. * and those at the high z limit. *
-C. * 'CONS' is a phi segment of a conical tube. It has 7 *
-C. * parameters, the same 5 as 'CONE' plus the phi limits.*
-C. * The segment starts at the first limit and includes *
-C. * increasing phi value up to the second limit or *
-C. * that plus 360 degrees. *
-C. * *
-C. ******************************************************************
-#if !defined(CERNLIB_SINGLE)
- IMPLICIT DOUBLE PRECISION (A-H,O-Z)
- REAL SNEXT, SNXT, SAFE
- PARAMETER (F=0.01745329251994330D0)
-#endif
-#if defined(CERNLIB_SINGLE)
- PARAMETER (F=0.01745329251994330)
-#endif
- REAL X(6),P(7)
-*
-* this part has to be moved outside the routine
- RO1=0.5*(P(4)+P(2))
- TG1=0.5*(P(4)-P(2))/P(1)
- CR1=1./SQRT(1.+TG1*TG1)
- RO2=0.5*(P(5)+P(3))
- TG2=0.5*(P(5)-P(3))/P(1)
- CR2=1./SQRT(1.+TG2*TG2)
- IF (IFL.EQ.2) THEN
- P6=P(6)*F
- P7=P(7)*F
- IF (P7.LT.P6) P7=P7+F*360.
- C1=COS(P6)
- S1=SIN(P6)
- C2=COS(P7)
- S2=SIN(P7)
- FIO=0.5*(P7+P6)
- CFIO=COS(FIO)
- SFIO=SIN(FIO)
- END IF
-*
- SNXT=1.E10
- R =SQRT(X(1)**2+X(2)**2)
- RIN =TG1*X(3)+RO1
- ROUT=TG2*X(3)+RO2
-*
-* Compute SAFE radius
- IF (IACT.LT.3) THEN
- SAF1=(R -RIN)*CR1
- SAF2=(ROUT-R)*CR2
- SAF3=P(1)-ABS(X(3))
- SAF4=1.E10
- IF (IFL.EQ.2) THEN
- IF ((X(2)*CFIO-X(1)*SFIO).LE.0.) THEN
- SAF4=ABS(X(1)*S1-X(2)*C1)
- ELSE
- SAF4=ABS(X(1)*S2-X(2)*C2)
- END IF
- END IF
- SAFE=MIN(SAF1,SAF2,SAF3,SAF4)
- IF (IACT.EQ.0) GO TO 999
- IF (IACT.EQ.1.AND.SNEXT.LE.SAFE) GO TO 999
- END IF
-*
-* Intersection with z-plane
- IF (X(6).GT. 1.E-20) THEN
- SZ= (P(1)-X(3))/X(6)
- ELSEIF (X(6).LT.-1.E-20) THEN
- SZ=-(P(1)+X(3))/X(6)
- ELSE
- SZ= 1.E10
- END IF
-*
-* Intersection with cones
-* Intersection point (x,y,z)
-* (x,y,z) is on track: x=X(1)+t*X(4)
-* y=X(2)+t*X(5)
-* z=X(3)+t*X(6)
-* (x,y,z) is on cone : x**2 + y**2 = (a*z+b)**2
-*
-* (X(4)**2+X(5)**2-(a*x(6))**2)*t**2
-* +2.*(X(1)*X(4)+X(2)*X(5)-a*x(6)*(a*x(3)+b))*t
-* +X(1)**2+X(2)**2-(a*x(3)+b)**2=0
-*
- T1=X(4)**2+X(5)**2
- T2=X(1)*X(4)+X(2)*X(5)
- T3=X(1)**2+X(2)**2
-*
-* Intersection with the inner cone
- SR1=1.E10
- IF (RO1.GT.0.) THEN
- U=T1-(TG1*X(6))**2
- V=T2- TG1*X(6)*RIN
- W=T3- RIN*RIN
-* track not parallel to the cone ?
- IF (U.NE.0.) THEN
- B=V/U
- C=W/U
- D=B**2-C
- IF (D.GE.0.) THEN
- DS=SQRT(D)
- IF (DS.GE.ABS(B)) THEN
- SR1= DS-B
- ELSEIF (B.LE.0.) THEN
- SR1=-DS-B
- END IF
- END IF
- ELSEIF (V.LT.0.) THEN
- SR1=-0.5*W/V
- END IF
- END IF
-*
-* Intersection with the outer cone
- SR2=1.E10
- U=T1-(TG2*X(6))**2
- V=T2- TG2*X(6)*ROUT
- W=T3- ROUT*ROUT
-* track not parallel to the cone ?
- IF (U.NE.0.) THEN
- B=V/U
- C=W/U
- D=B**2-C
- IF (D.GE.0.) THEN
- DS=SQRT(D)
- IF (DS.GE.ABS(B)) THEN
- SR2= DS-B
- ELSEIF (B.LE.0.) THEN
- SR2=-DS-B
- END IF
- END IF
- ELSEIF (V.GT.0.) THEN
- SR2=-0.5*W/V
- END IF
-*
-* Intersection with phi-planes
-* x=r*cos(phi)=X(1)+t*X(4)
-* y=r*sin(phi)=X(2)+t*X(5)
-* z =X(3)+t*X(6)
-* t=(X(2)*cos(phi)-X(1)*sin(phi))/(X(4)*sin(phi)-X(5)*cos(phi))
-*
- SFI1=1.E10
- SFI2=1.E10
- IF (IFL.EQ.2) THEN
-* track not parallel to the phi1 plane ?
- UN=X(4)*S1-X(5)*C1
- IF (UN.NE.0.) THEN
- S=(X(2)*C1-X(1)*S1)/UN
- IF (S.GE.0.) THEN
- XI=X(1)+S*X(4)
- YI=X(2)+S*X(5)
- IF ((YI*CFIO-XI*SFIO).LE.0.) SFI1=S
- END IF
- END IF
-* track not parallel to the phi2 plane ?
- UN=X(4)*S2-X(5)*C2
- IF (UN.NE.0.) THEN
- S=(X(2)*C2-X(1)*S2)/UN
- IF (S.GE.0.) THEN
- XI=X(1)+S*X(4)
- YI=X(2)+S*X(5)
- IF ((YI*CFIO-XI*SFIO).GE.0.) SFI2=S
- END IF
- END IF
- END IF
-*
- SNXT=MIN(SR1,SR2,SZ,SFI1,SFI2)
- 999 END
-
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