Analytical ray tracing system: Introducing art, a C-library designed for seismic applications

Ray tracing technique is an important tool not only to forward but also for inverse problems in Geophysics, which most of the seismic processing steps depend on. However, implementing ray tracing codes can be very time consuming. This article presents a computer library to trace rays in 2.5D media composed by a stack of layers. The velocity profile inside each layer is such that the eikonal equation can be analytically solved. Therefore, the ray tracing within such profile is made fast and accurate. The great advantage of an analytical ray tracing library is the numerical precision of the quantities computed and the fast execution of the implemented codes. Even though ray tracing programs exist for a long time, for example the seis88 package by Červený, most of those programs use a numerical approach to compute the ray. Regardless of the fact that numerical methods can solve more general problems, the analytical ones could be part of a more sophisticated simulation process, where the ray tracing time is completely relevant. We demonstrate the feasibility of our codes using several examples (Miqueles et al., 2013)  [1]. The library can also be used for other applications besides seismic, e.g., optics and tomography.Program summaryProgram title: artCatalogue identifier: AEQK_V1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEQK_V1_0.htmlProgram obtainable from: CPC Program Library, Queen’s University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 149519No. of bytes in distributed program, including test data, etc.: 2609188Distribution format: tar.gzProgramming language: C.Computer: Workstations and PCs.Operating system: Linux and Windows.RAM:  ≥2MbClassification: 2.9.External routines: LibConfuse (http://www.nongnu.org/confuse/).To run the examples included in the distribution file, gengetopt (http://www.gnu.org/software/gengetopt/gengetopt.html), Seismic Unix (http://www.seismicunix.com/w/Main_Page), gnuplot (http://www.gnuplot.info/) and SU.Nature of problem:Fast ray tracing algorithms for Seismic simulation and problems related to Wave propagation and/or Optics.Solution method:Method of characteristics for the eikonal equation, at a layered media, with analytical velocities.Running time:Milliseconds to 3 min, depending on the data size