[R] Error generated by nlme::gnls

[Aaron Crowley]

Approximately 6 months ago, I successfully performed a model-based
network meta-analysis using the gnls function from the nlme package in
R (nlme::gnls). In this analysis, a binary response is captured as a
non-linear non-parametric placebo response model combined with drug
effect as a function of dose and time and is fitted on aggregate data
from 57 trials and 13 treatments.

I am now trying to rerun the analysis but the code no longer runs. An
error message is generated when trying to fit the model using
nlme::gnls. A reproducible example generating the same error message
is below.

library(nlme)

set.seed(548)

df <- Soybean
df$x01 <- sample(c(0, 1), size = nrow(df), replace = TRUE)
df$x02 <- sample(c(0, 1), size = nrow(df), replace = TRUE)
df$x03 <- sample(c(0, 1), size = nrow(df), replace = TRUE)
df$x04 <- sample(c(0, 1), size = nrow(df), replace = TRUE)
df$x05 <- sample(c(0, 1), size = nrow(df), replace = TRUE)
df$x06 <- sample(c(0, 1), size = nrow(df), replace = TRUE)
df$x07 <- sample(c(0, 1), size = nrow(df), replace = TRUE)
df$x08 <- sample(c(0, 1), size = nrow(df), replace = TRUE)
df$x09 <- sample(c(0, 1), size = nrow(df), replace = TRUE)
df$x10 <- sample(c(0, 1), size = nrow(df), replace = TRUE)
df$x11 <- sample(c(0, 1), size = nrow(df), replace = TRUE)
df$x12 <- sample(c(0, 1), size = nrow(df), replace = TRUE)

gnls(
  weight ~ x,
  data = df,
  params = (x ~ -1 + x01 + x02 + x03 + x04 + x05 + x06 + x07 + x08 +
x09 + x10 + x11 + x12),
  start = rep(0, 13)
)
# Error in if (deparse(params[[nm]][[3]]) != "1") { :
#     the condition has length > 1

sessionInfo()
# R version 4.2.1 (2022-06-23 ucrt)
# Platform: x86_64-w64-mingw32/x64 (64-bit)
# Running under: Windows 10 x64 (build 22000)
#
# Matrix products: default
#
# locale:
#   [1] LC_COLLATE=English_United States.utf8  LC_CTYPE=English_United
States.utf8
# [3] LC_MONETARY=English_United States.utf8 LC_NUMERIC=C
# [5] LC_TIME=English_United States.utf8
#
# attached base packages:
#   [1] stats     graphics  grDevices utils     datasets  methods   base
#
# other attached packages:
#   [1] nlme_3.1-157
#
# loaded via a namespace (and not attached):
#   [1] compiler_4.2.1  tools_4.2.1     grid_4.2.1      lattice_0.20-45

Aaron Crowley
Principal Scientist, Biostatistics

e.  aaron using genesisrg.com
w. genesisrg.com