Calculates Sparse Population Moves to Minimize Population Deviation

This function computes a minimal set of population moves (e.g., 5 people from district 1 to district 3) to maximally balance the population between districts. The moves are only allowed between districts that share the territory of a county, so that any boundary adjustments are guaranteed to preserve all unbroken county boundaries.

min_move_parity(map, plan, counties = NULL, penalty = 0.2)

Arguments

map: a redist_map
plan: an integer vector containing the plan to be balanced. Tidy-evaluated.
counties: an optional vector of counties, whose boundaries will be preserved. Tidy-evaluated.
penalty: the larger this value, the more to encourage sparsity.

Value

a list with components:

moves: A tibble describing the population moves
pop_old: The current district populations
pop_new: The district populations after the moves

Examples

data(iowa)
iowa_map <- redist_map(iowa, existing_plan = cd_2010, pop_tol = 0.01)
min_move_parity(iowa_map, cd_2010)
#> $moves
#> # A tibble: 3 × 3
#>    from    to  move
#>   <int> <int> <dbl>
#> 1     2     1    35
#> 2     4     1     5
#> 3     3     4    23
#> 
#> $pop_old
#> [1] 761548 761624 761612 761571
#> 
#> $pop_new
#> [1] 761588 761589 761589 761589
#>