Example of using map2 to pass arguments to a model.

map2_example.R

# random modelling example for Stephen

# load in packages
librarian::shelf(rTPC,tidyverse, nls.multstart)

# create data
d <- chlorella_tpc %>%
  filter(curve_id < 4) %>%
  nest(data = c(everything(), -curve_id))

# lets have a look
d
d$data[[1]]

# create data frame of parameters to pass to each curve fit
# want to pass individual start values and individual lower limits
d_params <- tibble(curve_id = rep(1:3, each = 3), start_vals = c(get_start_vals(d$data[[1]]$rate, d$data[[1]]$temp, 'gaussian_1987'), get_start_vals(d$data[[2]]$rate, d$data[[2]]$temp, 'gaussian_1987'),get_start_vals(d$data[[3]]$rate, d$data[[3]]$temp, 'gaussian_1987')),
                   lower_lims = c(get_lower_lims(d$data[[1]]$rate, d$data[[1]]$temp, 'gaussian_1987'), get_lower_lims(d$data[[2]]$rate, d$data[[2]]$temp, 'gaussian_1987'),get_lower_lims(d$data[[3]]$rate, d$data[[3]]$temp, 'gaussian_1987'))) %>%
  nest(params = -curve_id)

d_params

# have a look at the first one
d_params$params[[1]]

# bind these into the data frame
d <- left_join(d, d_params)

d

# fit the model, can pass individual arguments to each fit using .y$
d <- mutate(d, fit = map2(data, params, 
                          ~nls_multstart(rate~gaussian_1987(temp = temp, rmax, topt, a), 
                                         data = .x, 
                                         start_lower = .y$start_vals -10, 
                                         start_upper = .y$start_vals + 10, iter = 100)))

d$fit[[1]]