C INCLUDE 'pointc.inc' C ------------------------------------------------------------------ INTEGER MYI PARAMETER (MYI=29) INTEGER ISRC,IWAVE,IRAY,IPT,NYF,ICB1F,ISRFF,KMAHF INTEGER NY,ICB1,ISRF,KMAH,ICB1I,IEND,ISHEET,IREC REAL XF,UEBRAF,YLF(6),YF(39),X,UEBRAY,YL(6),Y(39),YLI(6),YI(MYI) COMMON/POINTC/ISRC,IWAVE,IRAY,IPT, * NYF,ICB1F,ISRFF,KMAHF,XF,UEBRAF,YLF,YF, * NY ,ICB1 ,ISRF ,KMAH ,X ,UEBRAY,YL ,Y , * ICB1I,IEND,ISHEET,IREC,YLI,YI SAVE /POINTC/ C ------------------------------------------------------------------ C ISRC... Index of the source. The sources are indexed by positive C integers, see input file SRC. C IWAVE...Index of the elementary wave (output of the subroutine C CODE1). Elementary waves are indexed by 1,2,3,... . C IWAVE=0 if the end of the input file is encountered. C IRAY... Index of the ray (output of the subroutine RPAR2). Rays C within each elementary wave are indexed by 1,2,3,... . C Note that some of the indexed rays need not exist. C IRAY=0 if the end of the input file is encountered. C IPT... Index of the point on a ray. The points O/S are indexed C sequentially along each ray, taking the values 1,2,3,... C If the point is the first considered point of a new C elementary wave, IPT=0 instead of 1. C NYF,ICB1F,ISRFF,KMAHF,XF,UEBRAF,YLF,YF... Quantities at the point C O/F. They need not be defined (option in the subroutine C AP00). Their meaning is the same as of NY,ICB1,ISRF,KMAH, C X,UEBRAY,YL,Y below. C NYF=0... Indication that these quantities are not defined, C i.e. that the point O/F has not been defined. C NY,ICB1,ISRF,KMAH,X,UEBRAY,YL,Y... Quantities at the point O/S. C The detailed description of the quantities YL and Y may be C found in the file ray.for. C A brief description follows: C NY=IY(1)=27+NAMPL... Number of the basic quantities describing the C point of the ray, see the file 'ray.for'. C ICB1=IY(5)... Index of the complex block in which the stored point C of the ray is situated, supplemented by a sign '+' for P C wave and sign '-' for S wave. C ISRF=IY(6)... Index of the surface at which the endpoint of the C computed element of the ray is situated, supplemented by C a sign '+' or '-' for the endpoint situated at the C positive or negative side of the surface, respectively. C Zero inside the complex block. Note: The sign of this C quantity is the exception to the definition in the C original paper on C.R.T. C KMAH=IY(12)... Number of caustic points along the ray (the index C of the ray trajectory). C X=YY(1)... Independent variable along a ray. C UEBRAY=YY(2)... Upper error bound for ray tracing measured in C travel time. C Description of X and UEBRAY C YL... Array containing local quantities at the point of the ray, C see C C.R.T.5.5.4. C Description of YL C Y... Array containing basic quantities computed along the ray C see C C.R.T.5.2.1. C Description of Y C ICB1I,YLI,YI... Quantities at the initial point O/O of the ray: C ICB1I...Index of the complex block in which the initial point of C the ray is situated, supplemented by a sign '+' for P wave C and sign '-' for S wave, see C C.R.T.6.1. C IEND... Reason of the termination of the computation of a ray, see C C.R.T.5.4. C See subroutine RAY in the subroutine file 'ray.for' for C detailed description of IEND. C ISHEET..Ray-history index. The different ray histories are C consecutively indexed by positive integers 1,2,3,... C according to their appearance during ray tracing. C The ray histories are indexed independently within each C elementary wave. The indices are the output of subroutine C RPAR4 of the file 'rpar.for'. C The ray-history indices are complemented with sign: C positive - successful ray (crossing reference surface), C negative - unsuccessful ray (terminating before crossing C reference surface). C IREC... Index of the receiver for a two-point ray, C 0 for basic ray, C -1 for other rays (e.g., auxialiary or boundary rays). C YLI... Array containing the values of the quantities YL(1)-YL(6), C see C C.R.T.5.5.4, C describing the local properties of the model C at the initial point of the ray. See the list of C YL(1) to YL(6) in the file 'ray.for'. C Description of YL C YI... Array containing the quantities describing the properties C of the rays and of the travel-time field at the initial C point of the ray, see C C.R.T.6.1. C These quantities are listed in the file 'initc.inc'. C Description of YI C C The storage locations of the common block /POINTC/ are defined and C redefined in the external procedure AP00 of file 'ap.for'. C The quantities describing another point along a ray can be stored C into the common block /POINTC/ by another invocation of the C subroutine AP00. C C Common block /POINTC/ is included in FORTRAN 77 source code files C 'ap.for', 'apvar.for', 'crt2p.for', 'crtout.for', 'crtpts.for', C 'crtray.for', 'invtt.for', and may also be included in any user's C subroutine processing the results of the complete ray tracing C program. C C Date: 2004, June 10 C Coded by Ludek Klimes C C======================================================================= C