brownian_motion: Brownian Motion

In RandomWalker: Generate Random Walks Compatible with the 'tidyverse'

Brownian Motion

Description

Create a Brownian Motion Tibble

Usage

brownian_motion(
  .num_walks = 25,
  .n = 100,
  .delta_time = 1,
  .initial_value = 0,
  .dimensions = 1
)

Arguments

.num_walks	Total number of simulations.
.n	Total time of the simulation.
.delta_time	Time step size.
.initial_value	Integer representing the initial value.
.dimensions	The default is 1. Allowable values are 1, 2 and 3.

Details

Brownian Motion, also known as the Wiener process, is a continuous-time random process that describes the random movement of particles suspended in a fluid. It is named after the physicist Robert Brown, who first described the phenomenon in 1827.

The equation for Brownian Motion can be represented as:

W(t) = W(0) + sqrt(t) * Z

Where W(t) is the Brownian motion at time t, W(0) is the initial value of the Brownian motion, sqrt(t) is the square root of time, and Z is a standard normal random variable.

Brownian Motion has numerous applications, including modeling stock prices in financial markets, modeling particle movement in fluids, and modeling random walk processes in general. It is a useful tool in probability theory and statistical analysis.

Value

A tibble containing the generated random walks with columns depending on the number of dimensions:

• walk_number: Factor representing the walk number.

• step_number: Step index.

• y: If .dimensions = 1, the value of the walk at each step.

• x, y: If .dimensions = 2, the values of the walk in two dimensions.

• x, y, z: If .dimensions = 3, the values of the walk in three dimensions.

The following are also returned based upon how many dimensions there are and could be any of x, y and or z:

• cum_sum: Cumulative sum of dplyr::all_of(.dimensions).

• cum_prod: Cumulative product of dplyr::all_of(.dimensions).

• cum_min: Cumulative minimum of dplyr::all_of(.dimensions).

• cum_max: Cumulative maximum of dplyr::all_of(.dimensions).

• cum_mean: Cumulative mean of dplyr::all_of(.dimensions).

Author(s)

Steven P. Sanderson II, MPH

See Also

Other Generator Functions: discrete_walk(), geometric_brownian_motion(), random_normal_drift_walk(), random_normal_walk()

Examples

set.seed(123)
brownian_motion()

set.seed(123)
brownian_motion(.dimensions = 3) |>
  head() |>
  t()

RandomWalker documentation built on June 8, 2025, 12:15 p.m.