Fast Kaplan-Meier, Log-Rank, and Hazard Ratio Estimation for Survival Analysis R package FastSurvival version 0.1.0 Provides fast alternatives to standard survival analysis functions in the 'survival' package. The package implements a single-time-point Kaplan-Meier estimator (survfit_fast()), a log-rank test (survdiff_fast()), a closed-form hazard ratio estimator based on the Pike-Halley Estimator method (coxph_fast()), and a clinical trial data simulator (simdata_fast()). All functions are designed for repeated evaluation inside large simulation loops, such as adaptive sample-size re-estimation, probability-of-success calculations, and regional consistency evaluation in multi-regional trials. Core computations are implemented in 'C++' via 'Rcpp' for maximum performance. Methodological background is described in Collett (2014, ISBN:9780429196294). Software Depends: R (>= 4.1.0) Imports: dqrng, Rcpp LinkingTo: Rcpp, dqrng Suggests: survival, microbenchmark, testthat (>= 3.0.0), knitr, rmarkdown Gosuke Homma <my.name.is.gosuke@gmail.com> Comprehensive R Archive Network (CRAN) Gosuke Homma [aut, cre] MIT + file LICENSE (https://CRAN.R-project.org/package=FastSurvival/LICENSE) 2026-05-27 application/tgz https://CRAN.R-project.org/package=FastSurvival doi:10.32614/CRAN.package.FastSurvival en-US