permutate {gasanalyzer}

Expand a data frame with all possible combinations of the values in a column.

Description

For sensitivity analyses, it is useful to permutate the values in a single column, whilst keeping all other values constant. After creating such a permutation, recalculate() should be used to analyze the effect of the change in the column of interest. If the effect of changes in multiple columns is to be analyzed, this function can be called in series.

Usage

permutate(df, ...)

Arguments

df

a dataframe or tibble

...

a name-value pair. The name gives the name of the column in the input that is to be changed. The value is a vector specifying all values that are desired in the output. For every value in this vector, all other rows are duplicated.

Value

a data frame containing all possible combinations of the input df and the vector specified in ...

Note that the units and classes of the columns in the input data frame are applied to the replacement values. Unexpected behavior may occur when providing incompatible classes or units.

Examples

example <- system.file("extdata", "6400-testfile", package = "gasanalyzer")

# read data:
li6400 <- read_6400_txt(example)

# expand the data frame for a range of leaf areas, and recalculate the data:
li6400 <- permutate(li6400, Const.S = seq(1, 8)) |>
  recalculate(create_equations(c("default", "li6400")))

if (interactive()) {
  require(units)
  require(graphics)

  # observe that changing the leaf area enclosed in the chamber would have a
  # nonlinear effect on the rate of photosynthesis:
  aggregate(list(A = li6400$GasEx.A), list(Area = (li6400$Const.S)), mean) |>
    plot()
}