Algorithms for solving the two-point ray tracing in a 3D medium were developed. This study is devoted to the detailed description of the method used in solving the two-point problem. Using the algorithms designed, subroutines controlling the shooting have been coded. The procedures determine the initial conditions for computing the rays (i.e. ray parameters), and they are independent of an initial-value ray tracer. The already existing subroutine packages MODEL and CRT were used to calculate the rays in inhomogeneous 3D block models. The algorithms described were coded in Fortran 77.
Chapter 2 describes the fundamental ideas of the method of solving the two-point problem. The algorithm is described in detail, step by step, in Chapter 3. Chapter 4 contains remarks concerning the corresponding Fortran 77 code. For a numerical example of using the two-point ray tracing program refer to the preceding paper in this report.
This paper has been combined with
Bulant, P.: Numerical examples of two-point ray tracing in 3-D. In: Seismic Waves in Complex 3-D Structures, Report 3, pp. 65-92, Dep. Geophys., Charles Univ., Prague, 1995.
The resulting revised paper is
Bulant, P.: Two-point ray tracing in 3-D. PAGEOPH, 148(1996), 421-447.