quanti: Step by step: the model develops driven by field data
In PROSPER: Simulation of Weed Population Dynamics

Description Usage Arguments Details Value See Also Examples

This is a working horse of PROSPER. It quantifies the number or the proportion of individuals entering the next development stage using predefined formulas (formul). Typically these formulas are the results of experiments.

quanti(
  origin = NA,
  step_name,
  crop,
  proportion = TRUE,
  equal_dis = TRUE,
  res_max = NA,
  res_min = 0,
  formul = NA,
  area,
  addit_variables = NA,
  log_values = TRUE,
  back_log = TRUE
)

`origin`	numbers or log-numbers of individuals at the start for every genotype. `numeric`. Alternatively the columnaes of dfgenotype can be used.
`step_name`	step name in the database containing the model parameters. `character`.
`crop`	current crop in the crop sequence, must fit to one of the crop names in the data frame with weed-parameters. `character`.
`proportion`	`logical`, `TRUE` when the output should be a proportion, otherwise it will be an absolute number.
`equal_dis`	`logical`, `TRUE` when the distribution of the weeds is spatially uniform across the `area`.
`res_max`	output maximum, ignored when `origin=NA`. `numeric`.
`res_min`	output minimum. `numeric`.
`formul`	`character`. See details.
`area`	number of area units. `positive numeric`.
`addit_variables`	variables used in `formul` that are not predefined in `param.weed`. See details. `character vector`
`log_values`	logical, `TRUE` when `origin` in log-scale.
`back_log`	logical, `TRUE` when the output is in log-scale. Only used when `proportion==FALSE`.

Within PROSPER simulation models are build up with discrete simulation steps. These steps are conducted by functions like pop_step or gen_reprod. These functions affect the complete population and need a count of individuals or a proportion of the population that are affected of the specific simulation step. These numbers are calculated with quanti. The calculation is based on the data provided in weed-parameters. There a model is given for every parameter in the table. The parameter formul allows to use a different model if necessary. If no model is given at all, the simulation step is assumed to consist only of one value. The parameters of param.weed are normal distributed and the SE is used to draw them for the current calculation using rnorm(). These values are used to evaluate the model for simulation step. The resulting count or proportion can be used to perform the simulation step for the population.

Either a (log-)number of individuals or a proportion resp. a rate.

pop_step pop_germc weed-parameters

#loads the example data for Echinochloa crus-galli
data(param.ECHCG)
param.weed <- param.ECHCG
#how many seeds (natural, not log-scale) prodused by 100 plants in a corn stand on 100 area units?
quanti(origin=100, step_name="seed_prod_first", crop="corn",  proportion=FALSE,
                 area=100, log_values=FALSE, back_log=FALSE)
rm(param.ECHCG)