LayTracer: Fast two-point seismic ray tracing in layered media

LayTracer is an open-source Python package for computing ray paths, travel times, and path-dependent scalar quantities in horizontally layered (1D) velocity models. Version 0.5.0 adds ordered ray itineraries for prescribed reflected, transmitted, converted, and multiple paths, opt-in per-ray solver diagnostics, analytic sensitivities of traveltime and ray parameter to layer velocities, interface depths, and source and receiver positions, and linearized-ray and dense traveltime approximation APIs. Parallel trace_rays now returns each task's results as compact arrays that are copied into the output as the task finishes, so memory use is the output plus a few tasks per worker; this fixes MemoryError on large grids. The release also adds an optional complex coefficient product, corrects the spreading of reflected and multiple rays, requires NumPy 2 and Python 3.9 or newer, and declares all dependencies in pyproject.toml.