A convenience function for the path argument of build_hazard_data, useful when
there is no logged temperature series: when temperature follows a controlled linear
ramp, temp(t) = T_start + rate * t, the nominal ramp stands in for a logged
trace. It is vectorised over its arguments: give several ramps at once and it
stacks them into one table keyed by path_id.
Arguments
- path_id, T_start, rate, t_max
The ramp specification, one value per ramp:
path_idthe identifier,T_startthe start temperature,ratein degrees per time unit, andt_maxthe duration. The four are recycled together, so equal-length vectors describe several ramps and a length-one argument is reused across all of them.- by
An optional numeric giving the sampling step in time. When
NULL(the default) the path is just its two endpoints, which the linear interpolation in build_hazard_data reproduces exactly. A value such asby = 5creates a row everybytime units, which then serves as the check schedule in interval mode or a ready-made integration grid in continuous mode.
Value
A data frame with path_id, time and temp, ready to pass to
build_hazard_data as its path.
Examples
# One ramp: 20 -> 35 degrees over 60 minutes, as a two-point path.
ramp_path("A", T_start = 20, rate = 0.25, t_max = 60)
#> # A tibble: 2 × 3
#> path_id time temp
#> <chr> <dbl> <dbl>
#> 1 A 0 20
#> 2 A 60 35
# Two ramps at different rates, each sampled every 10 minutes (T_start recycled).
ramp_path(c("slow", "fast"), T_start = 20, rate = c(0.2, 0.4),
t_max = c(75, 40), by = 10)
#> # A tibble: 14 × 3
#> path_id time temp
#> <chr> <dbl> <dbl>
#> 1 slow 0 20
#> 2 slow 10 22
#> 3 slow 20 24
#> 4 slow 30 26
#> 5 slow 40 28
#> 6 slow 50 30
#> 7 slow 60 32
#> 8 slow 70 34
#> 9 slow 75 35
#> 10 fast 0 20
#> 11 fast 10 24
#> 12 fast 20 28
#> 13 fast 30 32
#> 14 fast 40 36