[R] Fleming-Harrington weighted log rank test

[array chip]

Hi all, 

The survdiff() from survival package has an argument "rho" that implements Fleming-Harrington weighted long rank test. 

But according to several sources including "survminer" package (https://cran.r-project.org/web/packages/survminer/vignettes/Specifiying_weights_in_log-rank_comparisons.html), Fleming-Harrington weighted log-rank test should have 2 parameters "p" and "q" to control the weighting for earlier vs later times in the follow-up.

For example, setting rho=1 in survdiff() uses the Peto-Peto modification of Gehan-Wilcox weights, which I can confirm by setting p=1 & 1=0 in comp() from survminer package. similarly rho=0 is equivalent to p=0 & q=0

I am interested in putting more weights on survival difference in later follow-up time. According to comp() from survminer package, that would set p=0 & q=1 for Fleming-Harrington weights. 

My question is how I can do the same by setting certain values for "rho" in the regular survival() function?

Thank you,

John