Skip to contents

Parameterise zoned parameters as an anchor value plus ratios

Source: R/zone_ratio.R
zone_ratio_param.Rd

Sediment zone parameters (e.g. aed_sed_const2d/fsed_oxy, sediment/sed_temp_mean) are normally calibrated as independent values per zone, which allows combinations that break the expected change with depth (e.g. zone 1 oxygen flux greater than zone 2). zone_ratio_param() replaces them with the value for zone 1 (the deepest zone), which is calibrated as usual, and one ratio per shallower zone. Each zone is a fraction of the next deeper zone, so zone2 = ratio2 * zone1 and zone3 = ratio3 * zone2, which guarantees that a shallower zone never exceeds a deeper one (in magnitude) when the ratios are within 0 and 1.

Usage

zone_ratio_param(param, n_zones, lower = 0.1, upper = 1, start = 0.5)

Arguments

param

data.frame of parameters for a single zoned parameter. Either one row (the zone 1 value) or one row per zone. The row with index == 1 (or the first row if index is missing) is the anchor.

n_zones

integer; number of zones in the model for this parameter.

lower, upper

numeric; bounds for the ratios.

start

numeric; starting value for the ratios when param has a single row. If param has one row per zone, starting ratios are derived from the zone values and clipped to the bounds.

Value

data.frame with the anchor row (index = 1) followed by n_zones - 1 ratio rows.

Details

The ratio rows are ordinary calibration parameters (named <name>_zratio). They are converted back to real per-zone values by expand_zone_ratios() immediately before the model files are written – input_model_parameters() does this itself – so no change to the model configuration is needed.

For quantities that do not scale sensibly as a ratio, such as sediment temperature, use zone_offset_param().

See also

zone_offset_param(), expand_zone_ratios()

Examples

p <- data.frame(model = "glm_aed", file = "aed.nml",
                name = "aed_sed_const2d/fsed_oxy", value = -30, min = -60,
                max = -5, group = NA_character_, index = 1)
zone_ratio_param(p, n_zones = 3)
#>     model    file                            name value   min max group index
#> 1 glm_aed aed.nml        aed_sed_const2d/fsed_oxy -30.0 -60.0  -5  <NA>     1
#> 2 glm_aed aed.nml aed_sed_const2d/fsed_oxy_zratio   0.5   0.1   1  <NA>     2
#> 3 glm_aed aed.nml aed_sed_const2d/fsed_oxy_zratio   0.5   0.1   1  <NA>     3