pomdp (version 1.0.0)

plot_belief_space: Plot a 2D or 3D Projection of the Belief Space

Description

Plots the optimal action, the node in the policy graph or the reward for a given set of belief points on a line (2D) or on a ternary plot (3D). If no points are given, points are sampled using a regular arrangement or randomly from the (projected) belief space.

Usage

plot_belief_space(
  model,
  projection = NULL,
  epoch = 1,
  sample = "regular",
  n = 100,
  what = c("action", "pg_node", "reward"),
  legend = TRUE,
  pch = 20,
  col = NULL,
  jitter_factor = 0,
  ...
)

Arguments

model

a solved POMDP.

projection

a vector with state IDs or names to project on. Allowed are projections on two or three states. NULL uses the first two or three states.

epoch

display this epoch.

sample

a matrix with belief points as rows or a character string specifying the method used for sample_belief_space.

n

number of points sampled.

what

what to plot.

legend

logical; add a legend? If the legend is covered by the plot then you need to increase the plotting region of the plotting device.

pch

plotting symbols.

col

plotting colors.

jitter_factor

y jitter for 2D belief spaces.

...

additional arguments are passed on to plot for 2D or TerneryPlot for 3D.

Value

Returns invisibly the sampled points.

See Also

Other POMDP: POMDP(), sample_belief_space(), simulate_POMDP(), solve_POMDP(), solve_SARSOP(), transition_matrix(), update_belief(), write_POMDP()

Examples

# NOT RUN {
# two-state POMDP
data("Tiger")
sol <- solve_POMDP(Tiger)

plot_belief_space(sol)
plot_belief_space(sol, n = 10)
plot_belief_space(sol, n = 10, sample = "random")

# plot the belief points used by the grid-based solver
plot_belief_space(sol, sample = sol$solution$belief_states)

# plot different measures
plot_belief_space(sol, what = "pg_node")
plot_belief_space(sol, what = "reward")

# three-state POMDP
# Note: If the plotting region is too small then the legend might run into the plot
data("Three_doors")
sol <- solve_POMDP(Three_doors)
sol

plot_belief_space(sol)
plot_belief_space(sol, sample = "random", n = 1000)
plot_belief_space(sol, what = "pg_node")
plot_belief_space(sol, what = "reward", sample = "random", n = 1000)

# plot the belief points used by the grid-based solver
plot_belief_space(sol, sample = sol$solution$belief_states)

# plot the belief points obtained using simulated trajectories (we use n = 50 to save time).
plot_belief_space(sol, sample = simulate_POMDP(Three_doors, n = 50, horizon = 100,
  random_actions = TRUE, visited_beliefs = TRUE))
# }