Error in if (pp < 0.025) { : missing value where TRUE/FALSE needed

[avish96]

The following code results in an error that I am unable to pinpoint the cause of. Any help would be appreciated!

## Loading libraries
library(ape)
library(treedater)

I first load my sample simulated time tree and simulate a rate tree from it, with one branch having a 10x higher rate than the rest.

## Read a sample time tree 
nwk_text <- '((((b_0_88:0.765387,b_0_140:3.12651)g_0_64:1.11098,(b_0_145:2.09135,b_0_189:3.73543)g_0_98:2.20924)g_0_45:2.25562,b_0_167:7.52794)g_0_12:0.442501,((b_0_42:0.493604,b_0_91:2.75931)g_0_30:0.405358,(b_0_44:0.530121,(((o_0_161:0.811279,o_0_306:0.811279)g_0_306:5.63543,b_0_249:3.0243)g_0_161:2.11281,(b_0_260:1.56686,(o_0_248:3.45721,o_0_216:3.45721)g_0_248:1.15911)g_0_216:3.9432)g_0_113:3.56052)g_0_37:0.54448)g_0_22:1.50395)g_0_9;'
v_t <- read.tree(text=nwk_text)  
v_t <- ladderize(v_t,right=FALSE)

## Number of edges
n_edge <- length(v_t$edge.length)

## Number of sites in sequence
nsites <- 1000

## Simulate rate tree, with a single branch rate different from others
v_r <- v_t
v_r$edge.length[-1L] <- rep(0.001,n_edge-1)
v_r$edge.length[1L] <- 0.01

I then calculate the substitution tree with my simulated time and rate trees, with the desired number of sites. I apply treedater to this substitution tree, using the root-to-tip distances for the sampling times, to obtain the inferred rate and time trees. I perform this operation 100 times.

for (i in seq_len(100)) {
  
  v_p <- v_t
  ## rate x time x sites = expected number of substitutions
  el <- v_r$edge.length * v_t$edge.length * nsites
  v_p$edge.length <- rpois(n=n_edge,lambda=el)/nsites
  
  ## Date-name matrix
  times <- diag(vcv(v_t)) # Getting root-tip distance for all tree tips
  names <- v_t$tip.label
  sts <- setNames(times, names)
  
  ## Date and obtain ratogram for substitution rate across branches
  v_est <- dater(v_p,sts=sts,clock='uncorrelated',s=nsites,ncpu=1) 
}

This results in the following error message in some simulations:

Error in if (pp < 0.025) { : missing value where TRUE/FALSE needed
In addition: Warning message:
In pnbinom(pmax(0, round(intree$edge.length * s)), size = r, prob = 1 -  :
  NaNs produced

Notes from preliminary investigations on my end: it seems like the pnbinom term returns NaN because intree$edge.length is a vector filled with NaN. pp is also NaN, as are p and td. I believe the size parameter r is infinity here, indicating the negative binomial converges to a poisson; I am unsure if this case is unaccounted for, and also wonder if this observation has anything to do with the shape of the likelihood landscape.

## Information on the R environment of the run
Sys.info()

sessionInfo()

[emvolz]

I have reproduced this and it is a bug. I agree that this is probably due to very low rate variation and divergence of the rate variation parameter. While I investigate further, there is a workaround: You can use the 'additive' clock model which will also give you an estimate of rate variation but seems to not have this bug.

[avish96]

Sounds good, thanks so much!