Compute cell centers

Rcpp alternative to compute_centers.

Usage

compute_centers_rcpp(agent, a, b, velocities, orientations, time_step = 0.5)

Arguments

agent

Object of the agent-class.

a, b

Numerics denoting the parameters of the weighting function, where a is used for the power of the function and b for the slope of function. a is required to be positive and b should lie between 0 and 1, where 1 - b denotes the maximal decrease in velocities in percentage.

velocities

Numeric matrix containing the change in speed for an agent whenever they move to the respective cell of this matrix.

orientations

Numeric matrix containing the change in direction for an agent whenever they move to the respective cell of this matrix.

time_step

Numeric denoting the number of seconds each discrete step in time should mimic. Defaults to 0.5, or half a second.

Value

Numeric matrix of (x, y) coordinates for each cell

Details

Compute cell centers based on a person's current position and velocity, accounting for potential changes in speed and direction. Alternative to c_vd that accounts for biomechanical limitations in the speed one can maintain when turning at a greater angle. Defaults are based on Seethapathi et al. (2024), Brown et al. (2020), and Glaister et al. (2007).

See also

agent-class, c_vd compute_centers moving_options

Examples

# Create two agents, one fast and one slow
slow_agent <- agent(center = c(-2.75, 0),
                    radius = 0.25,
                    speed = 0.5,
                    orientation = 0,
                    current_goal = goal(position = c(-2.01, 0)))

fast_agent <- agent(center = c(-2.75, 0),
                    radius = 0.25,
                    speed = 2,
                    orientation = 0,
                    current_goal = goal(position = c(-2.01, 0)))

# Generate the cell centers with predped
slow_centers <- compute_centers(slow_agent,
                                cpp = TRUE)
fast_centers <- compute_centers(fast_agent,
                                cpp = TRUE)

# Generate the cell centers with m4ma
slow_m4ma <- m4ma::c_vd(1:33,
                        position(slow_agent),
                        speed(slow_agent),
                        orientation(slow_agent))
fast_m4ma <- m4ma::c_vd(1:33,
                        position(fast_agent),
                        speed(fast_agent),
                        orientation(fast_agent))

# Compare both through a plot. This should show that the predped variant
# accounts for an interaction between an agent's speed and change in
# direction when computing the cell centers
base::plot(slow_centers, col = "black")
graphics::points(slow_m4ma[, 1], slow_m4ma[, 2], col = "red")


base::plot(fast_centers, col = "black")
graphics::points(fast_m4ma[, 1], fast_m4ma[, 2], col = "red")