Title: Power and Sample Size Calculation for Non-Proportional Hazards
Description: Performs power and sample size calculation for non-proportional hazards model using the Fleming-Harrington family of weighted log-rank tests. The sequentially calculated log-rank test score statistics are assumed to have independent increments as characterized in Anastasios A. Tsiatis (1982) <doi:10.1080/01621459.1982.10477898>. The mean and variance of log-rank test score statistics are calculated based on Edward Lakatos (1986) <doi:10.1016/0197-2456(86)90047-4> and Kaifeng Lu (2021) <doi:10.1002/pst.2069>. The boundary crossing probabilities are calculated using the recursive integration algorithm described in Christopher Jennison and Bruce W. Turnbull (2000, ISBN:0849303168).
Suggests: knitr, rmarkdown, rpact, mvtnorm

Description: Performs power and sample size calculation for non-proportional hazards model using the Fleming-Harrington family of weighted log-rank tests. The sequentially calculated log-rank test score statistics are assumed to have independent increments as characterized in Anastasios A. Tsiatis (1982) <doi:10.1080/01621459.1982.10477898>. The mean and variance of log-rank test score statistics are calculated based on Edward Lakatos (1986) <doi:10.1016/0197-2456(86)90047-4> and Kaifeng Lu (2021) <doi:10.1002/pst.2069>. The boundary crossing probabilities are calculated using the recursive integration algorithm described in Christopher Jennison and Bruce W. Turnbull (2000, ISBN:0849303168). The inverse normal combination method due to Lu Cui, H. M. James Hung, and Sue-Jane Wang (1999) <doi:10.1111/j.0006-341x.1999.00853.x> is used in the simulation study to accommodate the information time not proportional to the total number of events for weighted log-rank tests.

Description: Performs power and sample size calculation for non-proportional
hazards model using the Fleming-Harrington family of weighted log-rank
tests. The sequentially calculated log-rank test score statistics are
assumed to have independent increments as characterized in
and variance of log-rank test score statistics are calculated based on
Kaifeng Lu (2021) <doi:10.1002/pst.2069>. The boundary crossing probabilities
are calculated using the recursive integration algorithm described in
Christopher Jennison and Bruce W. Turnbull (2000, ISBN:0849303168).
Suggests: knitr, rmarkdown, testthat (>= 3.0.0), mvtnorm