Covariates in the model prevent sampling times from being generated at run time.

[crgfn]

Below is the verbatim code from the "Individual Covariates" Article, with the event table sampling line commented out. After running, no samples are output. This still happens even when explicitly requesting samples in solve using length.out

dim(r1)
[1]  0 17

mod3 <- function() {
  ini({
    TKA   <- 2.94E-01
    TCL   <- 1.86E+01 
    TV2   <-4.02E+01
    TQ    <-1.05E+01
    TV3   <-2.97E+02
    TKin  <- 1
    TKout <- 1
    TEC50 <-200
  })
  model({
    KA            <- TKA
    CL            <- TCL * (WT / 70) ^ 0.75
    V2            <- TV2
    Q             <- TQ
    V3            <- TV3
    Kin           <- TKin
    Kout          <- TKout
    EC50          <- TEC50
    Tz            <- 8
    amp           <- 0.1
    C2            <- central/V2
    C3            <- peri/V3
    d/dt(depot)   <- -KA*depot
    d/dt(central) <- KA*depot - CL*C2 - Q*C2 + Q*C3
    d/dt(peri)    <-                    Q*C2 - Q*C3
    d/dt(eff)     <-  Kin - Kout*(1-C2/(EC50+C2))*eff
    eff(0)        <- 1  ## This specifies that the effect compartment starts at 1.
  })
}

ev <- et(amount.units="mg", time.units="hours") %>%
  et(amt=10000, cmt=1) %>%
  #  et(0,48,length.out=100) %>% 
  et(id=1:4)

set.seed(10)
rxSetSeed(10)
r1 <- solve(mod3, ev,
            iCov=data.frame(id=1:4, WT=rnorm(4, 70, 10)))

[mattfidler]

I can reproduce this bug:

library(rxode2)
#> rxode2 4.0.0.9000 using 11 threads (see ?getRxThreads)
#>   no cache: create with `rxCreateCache()`

mod3 <- function() {
  ini({
    TKA   <- 2.94E-01
    TCL   <- 1.86E+01 
    TV2   <-4.02E+01
    TQ    <-1.05E+01
    TV3   <-2.97E+02
    TKin  <- 1
    TKout <- 1
    TEC50 <-200
  })
  model({
    KA            <- TKA
    CL            <- TCL * (WT / 70) ^ 0.75
    V2            <- TV2
    Q             <- TQ
    V3            <- TV3
    Kin           <- TKin
    Kout          <- TKout
    EC50          <- TEC50
    Tz            <- 8
    amp           <- 0.1
    C2            <- central/V2
    C3            <- peri/V3
    d/dt(depot)   <- -KA*depot
    d/dt(central) <- KA*depot - CL*C2 - Q*C2 + Q*C3
    d/dt(peri)    <-                    Q*C2 - Q*C3
    d/dt(eff)     <-  Kin - Kout*(1-C2/(EC50+C2))*eff
    eff(0)        <- 1  ## This specifies that the effect compartment starts at 1.
  })
}

ev <- et(amount.units="mg", time.units="hours") %>%
  et(amt=10000, cmt=1) %>%
  #  et(0,48,length.out=100) %>% 
  et(id=1:4)

set.seed(10)
rxSetSeed(10)
r1 <- solve(mod3, ev,
            iCov=data.frame(id=1:4, WT=rnorm(4, 70, 10)))
#> ℹ parameter labels from comments are typically ignored in non-interactive mode
#> ℹ Need to run with the source intact to parse comments
#> using C compiler: ‘gcc (Ubuntu 11.4.0-1ubuntu1~22.04) 11.4.0’

print(r1)
#> ── Solved rxode2 object ──
#> ── Parameters ($params): ──
#>     TKA     TCL     TV2      TQ     TV3    TKin   TKout   TEC50      Tz     amp 
#>   0.294  18.600  40.200  10.500 297.000   1.000   1.000 200.000   8.000   0.100 
#> ── Initial Conditions ($inits): ──
#>   depot central    peri     eff 
#>       0       0       0       1 
#> ── First part of data (object): ──
#> # A tibble: 0 × 17
#> # ℹ 17 variables: id <int>, time [h], KA <dbl>, CL <dbl>, V2 <dbl>, Q <dbl>,
#> #   V3 <dbl>, Kin <dbl>, Kout <dbl>, EC50 <dbl>, C2 <dbl>, C3 <dbl>,
#> #   depot <dbl>, central <dbl>, peri <dbl>, eff <dbl>, WT <dbl>

^{Created on 2025-04-25 with reprex v2.1.1}